GrowingKiwifruit

PNW 507 • Reprinted September 2000$2.50

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Contents

Bernadine Strik, Extension berrycrops specialist, and Helen Cahn,research assistant, Oregon StateUniversity.

This publication replaces Oregonpublication EC 1464, GrowingKiwifruit.

Kiwifruit Cultivars“Fuzzy” Kiwifruit ....................................................................... 2

Hardy Kiwi ................................................................................. 3

Kolomikta Kiwi .......................................................................... 4

Silver Vine Kiwi ......................................................................... 5

Establishing Your Kiwifruit VineyardSite Selection and Preparation .................................................... 6

Vineyard Planning, Planting, and Spacing ................................. 7

Irrigation ..................................................................................... 8

Fertilization............................................................................... 10

Trellis ........................................................................................ 11

Training Young Vines ............................................................... 12

Maintaining Your Kiwifruit VineyardFertilization............................................................................... 15

Irrigation ................................................................................... 16

Pollination................................................................................. 16

Fruit Thinning ........................................................................... 16

Pruning and Training ................................................................ 17

Harvest, Handling, andStorage of Kiwifruit

Fruit Maturation........................................................................ 19

Harvesting................................................................................. 20

Storage ...................................................................................... 20

1

Kiwifruit Cultivars

Although some people claimthey eat the skin of fuzzy kiwi,most peel these fruit. However,the hardy, kolomikta, and silvervine kiwifruit have very edibleskin. You can pop these delicious,small fruit right into your mouth.

Kiwifruit are relatively high inacid, reaching nearly 2 percent offresh weight at maturity anddeclining after harvest. Kiwifruitare one of the best natural sourcesof vitamin C, with a level of atleast twice that of the orange.

The fruit of most commonkiwifruit species and cultivarshave green flesh that does notbrown when cut.

Fuzzy kiwifruit can be storedfor months after harvest. However,the hardy and kolomikta kiwis canbe stored for only 2 months atmost at 32–35.5°F (0–2°C).

The kiwifruit is a dioeciousplant—it has separate male andfemale plants (with the exceptionof a few self-fertile cultivars). It isessential to plant male vines forpollination and crop production.

Plant male and female vines ofthe same species. In general,1 male is required for every 6 to10 females. Self-fertile cultivarsrequire no male pollinator, al-though fruit size may be largerwith cross-pollination.

Yield per plant varies withspecies and cultivar. Hayward(A. deliciosa) yields from 25 to

B. Strik and H. Cahn

Kiwifruit arenative tosoutheast Asia.There are morethan 50 species in

the genus Actinidia, and manyhave commercial potential.

The most common kiwifruitspecies grown commercially isActinidia deliciosa cultivarHayward. Consumers are veryfamiliar with this brown, fuzzyfruit.

Fuzzy kiwi are grown commer-cially in New Zealand, Italy,Japan, France, Australia, Greece,Chile, and California. There issome commercial production inOregon and Washington; however,this species is not extremely hardyand may suffer cold injury insome years in the Pacific North-west.

More hardy kiwifruit speciesalso are available. They includethe following:

• A. arguta, known as the hardykiwi or arguta (marketed asbaby kiwi in Oregon and grapekiwi in British Columbia). Thisspecies shows promise forcommercial production in the

United States.

• A. kolomikta, alsoknown as kolomiktaor Arctic Beauty

• A. polygama, orsilver vine

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HaywardHayward is the cultivar usually

found in stores. Its large, fuzzy,brown fruit with good, sweetflavor has made it popular. Shootsare sensitive to frost injury inspring. This cultivar is recom-mended only for areas of Oregonand Washington with mildwinters.

Ripening date: October 7–12Fruit weight: 80–90 gramsVine growth: vigorous

BrunoBruno produces a large cylin-

drical fruit that is darker brownthan Hayward. It has a lowerwinter chilling requirement(50–250 hours at 32 to 45°F), andtherefore may be more sensitive tolate winter cold spells, particularlyafter a warm period.

Saanichton 12This cultivar comes from

Vancouver Island, British Colum-bia, where it has been grown formore than 30 years. Fruit arelarge, somewhat more rectangularthan Hayward, sweet, and of goodflavor. It seems more hardy thanHayward.

Ripening date: October 1Fruit weight: 70–80 gramsVine growth: vigorous

BlakeThis is a relatively new cultivar.

It is claimed to be “self-fertile,”but it does benefit from cross-pollination. Fruit are smaller thanHayward or Saanichton 12 and aremore oval in shape. Flavor isinferior to Hayward andSaanichton 12.

Ripening date: October 1Fruit weight: 60–70 gramsVine growth: vigorous

200 pounds per plant, whereasA. arguta yields from 50 to100 pounds per plant.

A. kolomikta and A. polygamaleaves contain a substance that hasan effect similar to catnip. InChina, kiwivine leaves reportedlyare fed to large cats as a sedative.You may find that cats become apest of your new kiwifruit plant-ing!

The information below onripening dates, fruit weights, andplant performance is approximate.It is based on limited test resultsfrom a cultivar planting at NorthWillamette Research and Exten-sion Center (NWREC), Aurora,Oregon. Performance may varywith location.

“Fuzzy” KiwifruitActinidia deliciosa, fuzzy

kiwifruit, is the most widelyavailable species. Generally, fruitare large, with a green skincovered with brown fuzz. VitaminC content ranges from 100 to200 mg per 100 grams fruit. Themost common commercial culti-var is Hayward, which is found insupermarkets throughout theworld. However, other varietiesalso are available.

Fuzzy kiwifruit can be grown inOregon and Washington. Haywardneeds a growing season of about225 to 240 frost-free days. How-ever, although this species shouldtolerate temperatures down to10°F (-12°C), plants may bedamaged at slightly higher tem-peratures.

Cold damage usually occurswhen temperatures drop duringthe night after a warm spell. Thetrunk usually is damaged, whichweakens older plants and some-times kills young vines. Althoughmethods such as wraps and plasticsleeves may help protect the trunkagainst freeze injury, they are notalways effective. The trunk’ssensitivity to cold decreases withage.

Young kiwifruit shoots and fruitare very sensitive to frost injury.Temperatures of 30°F or less(-1°C) for only 30 minutes canseverely damage shoots in thespring and fruit in the fall. Still,these kiwifruit can be grownsuccessfully with overheadirrigation for frost protection.

Although many other fuzzykiwifruit cultivars are available in

other productionregions, the follow-

ing cultivars areavailable and havebeen tested in thePacific Northwest.All produce brightgreen-fleshed fruit.

Ripening datesgiven below are based

on when fruit reached6.5 °Brix (percent sugar) at

NWREC, a harvest datecriterion for long-term storage

(see “Harvest, Handling, andStorage of Kiwifruit”).

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Male (A. deliciosa)A pollinator is required for all

fuzzy kiwi. There are manycultivars/selections of malesavailable. Examples includeMatua, Tomuri, Cal Chico No. 3,Chico Early, and Chico ExtraEarly.

Hardy KiwiThis kiwifruit species,

A. arguta, is hardy to -10 to -25°F(-23 to -32°C) under most condi-tions. Damage to the trunk fromcold temperatures rarely occurs inOregon or Washington; however,frost damage to young shoots ismore common.

Maximum hardiness levelsgiven for this species reflect onlymidwinter hardiness. This specieshas a low chilling requirement(winter rest period satisfied bytemperatures at 32–45°F) and maybe sensitive to cold injury athigher temperatures when warmweather precedes a cold spell,particularly in late winter.

Unfortunately, warm tempera-tures in February or March maypromote early bud break, makingthis species very susceptible tofrost damage of the young shoots.Only additional testing will showhow much of a problem this maybe for our region.

Keep in mind that young vinesmay be more cold sensitive.Protect them with trunk wraps(see “Establishing Your KiwifruitVineyard”).

Hardy kiwi plants are veryvigorous and produce a goodquality, highly aromatic fruit thatis quite different from the fruit of

A. deliciosa. Fruit are smoothskinned (skin can be eaten),generally green in color, and muchsmaller than the fuzzy types. Theflavor is excellent, but varies bycultivar. Vitamin C content isvery good at 10 to 70 mg per100 grams fresh fruit.

In France, hardy kiwi arecultivated commercially, butacreage is limited due to market-ing limitations—small fruit size,short shelf life, and a limitedripening period. Also, the fruit ona given plant ripen unevenly,which makes harvest difficultunless fruit are picked under-ripeand forced to ripen. Vines are veryvigorous, and considerablepruning is required to keep growthunder control.

In general, hardy kiwifruit donot store as well as the fuzzytypes. Therefore, you likely willsee these kiwifruit in stores up toonly a couple of months after fallharvest.

Currently, relatively little hardykiwifruit is grown commercially.However, you no doubt will hearand see more about these types, asthey do have good quality, attrac-tive fruit.

Certainly, the hardy kiwifruitare well suited to the home gardenand, with an appropriate market,to commercial production as well.

Fruit of these hardy kiwi arebest when ripened on the vine tomaximize development of aromaand flavor; however, shelf-lifethen is shortened. The followingharvest dates are based on sugarlevels of 8 to 9 °Brix. (If left onthe vine, the fruit will reach 18 to25 °Brix.)

AnanasnayaThis is the most popular hardy

kiwifruit cultivar currently avail-able. Its Russian name means“pineapple-like.” You also mayhear this cultivar referred to as“Anna.”

Fruit are of very good quality,with a good aroma and sweet,intense flavor. They have a greenskin that develops a purple-redblush in full sun. Skin may beslightly tough.

The cultivar Ananasnayabrought to Oregon is A. arguta.However, the Russian cultivarAnanasnaya is A. kolomikta;more than one cultivar with thesame name may be available innurseries.

Harvest date: September 14–30Fruit weight: 9–14 gramsVine growth: very vigorous

74-49This numbered selection/

cultivar came from a USDAprogram in Chico, California.This cultivar produces very goodquality fruit of similar size andquality to Ananasnaya.

Ripening date: September 7–14Fruit weight: 7–12 gramsVine growth: very vigorous

MeaderWe presently are not testing this

cultivar at NWREC. However, it isreported to produce good quality,medium-sized fruit. Note that amale “Meader” also is available;do not be confused.

Kiwifruit Cultivars

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A. arguta var. cordifoliaNot yet widely tested in the

Pacific Northwest. Fruit arereputed to be of good flavor andvery sweet. Plants are veryvigorous and produce high yields.Flowers may be wind pollinated.

Ken’s RedNot widely tested in the Pacific

Northwest, this kiwifruit fromNew Zealand is a cross ofA. arguta var. cordifolia andA. melanandra. Fruit are nearlysquare to cylindrical with a “nib”at the tip. They are bright green insummer and turn red-skinned latein the season. Vines are veryvigorous.

GenevaThis cultivar has not been

widely tested in the PacificNorthwest, although there arepreliminary results from BritishColumbia. Plants ripen earlierthan Issai and Ananasnaya and areabout the same size. Fruit have agood flavor.

Issai (self-fertile)This cultivar from Japan is less

vigorous than the other hardykiwifruit cultivars listed above.Fruit are smaller in size, some-what cylindrical, come to a point,and are fully green. Flavor andaroma are very good. Harvestingis somewhat more difficult thanthe other hardy kiwi, because fruitare smaller and ripen ratherunevenly within a cluster. Thiscultivar, although self-fertile,produces larger fruit with seedswhen cross pollinated. Vines are

slightly less hardy than otherA. arguta at 0 to -10°F (-18 to-23°C).

Harvest date: September 1–4Fruit weight: 4–9 gramsVine growth: moderate vigor

with lower yield per vine than theother hardy kiwi.

MalePollinator for above A. arguta

species. About 1 male is neededfor every 8 females. There isevidence that A. arguta cultivarscan be pollinated by A. deliciosamales, which produce more pollenthan the arguta males. However,A. deliciosa males are much lesshardy than A. arguta males; thusyou risk crop loss to cold injurywhen using the fuzzy males.

Other cultivars/selections thatmay be available includeDumbarton Oaks, 74-45, 74-8,and Michigan (reported to havealmost twice the fruit size ofAnanasnaya). However, thesehave not been tested in Oregon.

Kolomikta KiwiThese kiwi types, A. kolomikta,

are hardy to -40°F (-40°C), butshoots are sensitive to frostdamage. In the Willamette Valley,Oregon, A. kolomikta cultivarshave been found to break budearlier than arguta types in latewinter. For example, all shootswere killed by cold in February1995. Available cultivars differgreatly in fruit shape, size, color,and flavor. Fruit of kolomikta aresmaller than those of argutakiwivines. Plants are consideredgood ornamentals because of their

variegated pink leaves, particu-larly in the male.

The fruit are small to mediumsized, but are very sweet, withgood aroma and flavor. Fruit arevalued for their exceptionally highvitamin C content—700 to 1,000mg/100 grams fruit (10 timeshigher than Hayward and 20 timeshigher than citrus).

Fruit are best when ripened onthe vine to maximize aroma andflavor development; however,shelf life then is shortened.

It has been difficult to establishA. kolomikta at NWREC. Vinesplanted in 1990, even after4 years, grew little and producedalmost no yield. Thus, it is hard toevaluate their performance relativeto the hardy kiwi.

Perhaps this species is moresensitive to wet soil or phytoph-thora root rot—a possible reasonfor its poor growth at NWREC.There also are reports thatA. kolomikta requires some shadefor optimal growth. This speciesalso has not performed well intrials in British Columbia.

Nevertheless, the followingcultivars may perform well atother sites and certainly wouldmake good ornamental fruit plantsin the home garden. This speciesdoes not have the commercialpotential of A. arguta.

KrupnopladnayaThis cultivar, “large fruit” in

Russian, is the largest of the arcticbeauties tested in Oregon. Flavoris good and sweet. Plants havelow to moderate vigor comparedto A. deliciosa.

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PautskeThis is the most vigorous of the

arctic beauties tested in Oregon.Fruit are large and of good quality.Plants are more vigorous thanthose of Krupnopladnaya, but stillhave lower vigor than A. deliciosa.

MaleA. kolomikta male needed to

pollenize the above cultivars.

Kiwifruit Cultivars

Silver Vine KiwiThis species of kiwifruit, A.

polygama, is called silver vine forthe silvery-white color of theyoung leaves. Fruit have orangeskin and flesh, and are cylindricalwith a point at the base. Althoughseveral sources say fruit are ediblewith a sweet, peppery taste whenripe, we have not had goodsuccess with this species atNWREC. Our fruit goes fromgreen and unripe to orange andsoft with an astringent peppery

flavor. Plants are moderatelyvigorous, but more susceptible tocold injury than arguta orkolomikta. Some clones are self-fertile.

This species does not havemuch potential for commercialfruit production. However, it doesmake a nice ornamental.

Harvest date: September 1–4Fruit weight: 6–9 gramsVine growth: moderate to low

vigor at NWREC

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Vine growth andfruiting habit ofboth fuzzy andhardy kiwifruit aresimilar. The

following information on vineyardestablishment applies to all theaforementioned species unlessdifferences are noted.

Site Selectionand Preparation

Proper site selection, soilpreparation, irrigation systemdesign, planting design, andtraining are essential to develop-ing a productive kiwifruit vine-yard.

Site selectionThe single most limiting factor

for fuzzy kiwifruit production istemperature. A. deliciosa Haywardcan withstand temperatures as lowas 10°F (-12°C). Although thebuds of Hayward have a highchilling requirement (700 to800 hours), the vines are veryprone to frost injury during thegrowing season. Cold injury toHayward has occurred in somewinters in the Pacific Northwest.

Dormant A. arguta vines aremuch more cold hardy than thefuzzy types (to -10 to -25°F or -23to -32°C). However, young vinesof this species also can suffer

winter injury, particularly to thetrunk, if temperatures fluctuatefrom warm to cold in late winter.A. arguta vines also are sensitiveto spring frost damage to youngshoots.

Male vines are less hardy thanfemale vines (documented inOregon).

There are several ways to helpprevent freeze and frost injury:

• Do not plant in low areas orcool sites.

• Remove barriers (e.g., trees) tocold air drainage.

• Keep in mind that clean,cultivated sites are warmerduring frost periods than siteswith permanent cover crops.

• Do not cultivate immediatelyprior to a projected frost,because this reduces heattransfer from soil to air at night.

• Use overhead irrigation systemsin areas susceptible to latespring frosts (see “Irrigation”).

Chemicals that reduce vinetranspiration (i.e., anti-desiccants)have not been shown to reducefrost injury in kiwifruit.

SoilKiwi vines do best in deep,

well-drained soils. They are verysensitive to standing water,especially after bud break inspring. Research in New Zealand

Establishing YourKiwifruit VineyardB. Strik

7

has shown that if roots are water-logged for 3 days or more, the rootsystem and vine growth areseverely damaged.

In California, it is recom-mended that kiwifruit be plantedon 3 feet of well-drained soil.However, Hayward vines havegrown well on soils with aneffective rooting depth of 2 feet,provided the water table is lowerthan this.

Another option is to plant vineson raised beds (at least 1 foothigh). This is advisable in heavysoils, since it also may protectagainst phytophthora root rots.

Install well-designed drain tilesto improve drainage if necessary.Ripping the soil below the rowbefore planting also can benefitgrowth.

The optimum pH for Haywardis between 5.5 and 6.0. Vinesshow poor growth at a pH above7.2. It is not known if otherspecies differ in pH requirements.

Previous cropping historyKiwifruit are susceptible to

verticillium wilt. Avoid planting insoils with a history of strawberry,black raspberry, potatoes, or othersolanaceous crops.

Plants also are sensitive tophytophthora and root knotnematodes (Meloidogyne spp.).Although the literature relates toHayward, it’s best to assume thatarguta is similarly sensitive.Kiwifruit also are susceptible toArmillaria oak root fungus, whichmay be present on sites previouslyplanted to oak trees.

A preplant soil test for nema-todes is recommended. If nema-todes or oak root fungus arepresent, use a preplant fumigation.

Table 1.—Irrigation water guidelines.

chloride < 70 ppmbicarbonate < 200 ppmboron < 0.25 ppmsodium < 50 ppmelectrical conductivity, EC x 10 < 0.75

Establishing Your Kiwifruit Vineyard

Young kiwifruit vines competepoorly with weeds, so eliminate asmany perennial weeds as possiblebefore planting. A permanentcover crop or a natural weed stripmay be maintained between rows.

WaterA plentiful supply of good

quality water is required forkiwifruit production. Plants need40–48 acre-inches of water a year.Table 1 shows irrigation guide-lines that are considered safe inCalifornia.

Wind damageLong shoots in spring and

summer are very susceptible towind damage or breakage. Notonly can wind cause fruit loss, butit also may reduce economicyields by rubbing the fruit. Whenrubbed, fuzzy kiwi first lose their“fuzz” and then develop callus,whereas the hardy types develop acallused or scabbed area.

In windy areas, wind breakssuch as poplars help reduceeconomic losses. Plant windbreaks to provide 200 to 250 feetof protection downwind. Makesure wind breaks are not plantedclose enough to the vineyard rowsto reduce yield of the kiwifruit.

VineyardPlanning, Planting,and Spacing

It costs from $8,000 to $12,000per acre, not including land cost,to establish a kiwifruit vineyardand bring it to production. It takes3 or more years after planting toproduce a commercial crop.

Planting designFor a T-bar trellis, vines com-

monly are planted 15 to 18 feetapart in rows 15 feet apart,resulting in 160 to 190 plants peracre. For the pergola, you maywant to space rows 20 feet apart(see “Trellis”).

Kiwifruit vines are extremelyvigorous. Canes grow 6 to 12 feetper year, and occasionally 20 feet.Higher density plantings mayincrease production in the earlyyears, but in later years, over-growth and shading will requireexcessive summer pruning.

The kiwifruit is a dioeciousplant—it has separate male andfemale plants (with the exceptionof a few self-fertile cultivars).Male vines are essential forpollination and crop production.

In general, plant the samespecies of male as the femalevines. Although A. deliciosa malesare reported to be good pollinatorsof A. arguta females, they are

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much less cold hardy than argutamales, and thus increase the riskof crop loss to cold damage.

Male and female vines must bepresent in a block and must flowerat the same time. In general, plantabout 1 male plant for every 6 to10 female plants.

You can achieve a 1:8 male-female ratio with the followingdesign:

• Plant only female plants in alloutside rows.

• Plant the following row with amale plant between every twofemale plants.

• Plant the next 2 rows of allfemale plants.

• Plant another row with a maleplant between every twofemales.

• Plant 2 more rows of all femaleplants.

• Continue as above.

If you plant a male every thirdvine in every second row, the ratiois 1:6.

Male plants in these plantingsystems run at right angles to therows. For T-bar systems, you maywant to place males in every row,as there is some evidence that beesprefer to work down rows ratherthan across.

PlantingSelf-rooted vines perform better

in the Northwest’s cold winters.Although grafted kiwifruit areavailable from many nurseries,planting kiwifruit on their ownroots in areas where cold injurymay occur is recommended.Severe cold spells can kill agrafted vine past the graft union,

thus killing the vine. On cold-injured, self-rooted vines, suckerscan be trained up from below thewinter-killed portion.

Using rootstocks in kiwifruitproduction could offer manyadvantages:

• Reduced plant-to-plant variability

• Vigor reduction

• Greater tolerance for adversesoil conditions such as water-logging

• Greater physiological coldtolerance

• Resistance to pests or diseases

• More precocious and higher-yielding vines

However, research needs to bedone on rootstock possibilities inkiwifruit.

Plant 2-year-old bare-root orcontainer stock. If grafted, thescion (fruiting portion) shouldhave been grown for one seasonbefore purchase.

Purchase bare-root nurserystock as close to planting time aspossible. Don’t allow the roots todry out. Plant as early in thespring as possible. Container-grown plants can be planted at anytime except midsummer.

It’s a good idea to plant onraised beds to reduce risk ofphytophthora. Carefully markyour field prior to planting.Planting all males first and thenfilling in with females is recom-mended.

Install your irrigation systembefore planting (see “Irrigation”).Establish your trellis prior to, orjust after, planting (see “Trellis”).Place the row posts betweenplants so that if post repair is

needed, the vine trunk is not inthe way.

Make the planting hole largeenough to accommodate the rootswithout bending them. You maytrim the roots a little to makethem fit the hole. Do not dig thehole deeper than needed. Do notadd any fertilizers, includingmanures, to the planting hole, asthe roots are very sensitive tofertilizer burn.

Plant vines deeply enough justto cover the top roots. Nevermound soil around the plant.Keep the soil moist enough topromote root growth, but don’tover-water, which can causeanaerobic conditions that promoteroot rots.

You can paint the trunks with amixture of 1:1 water and interiorwhite latex to help preventsunburn. Milk cartons also canprotect against sunburn androdent feeding. Place a trunkwrap around all species ofkiwifruit vines. This helps reducethe risk of cold injury to thesusceptible young vines.

IrrigationGood irrigation is critical for

good growth and production.Irrigate young plants enough towet the root zone without keepingthe crown too wet; otherwise,crown or root rot may occur. Inyoung plants, the range betweentoo wet and too dry is narrow.

Unfortunately, there is rela-tively little direct experience onwater requirements of hardykiwifruit in the Pacific Northwest.The following information relates

9

to Hayward production, butshould be a good starting point forother cultivars as well.

Growers often irrigate byexperience rather than irrigationscheduling tools. In kiwifruit,however, observing vines fortrouble signs doesn’t work well,because by the time water stresssymptoms are visible, damage hasoccurred.

Vines under mild or moderatewater stress have a subtle off-colorlook, with the foliage turningblue-green. Other symptomsinclude poor shoot growth,wilting, small fruit, sunburn, andreduced yield in the current andfollowing season.

There are various types ofirrigation systems. Unfortunately,there is no single best system.Design a system that can supplyan average of 25 to 35 gallons ofwater per mature vine per dayduring the growing season.Irrigate vines once or twice perweek. Surface mulch may helpconserve soil moisture.

Drip systemsDrip systems economize on

water use, but on lighter soilsoften supply water to only anarrow cone of soil. Frequentirrigations are necessary, particu-larly to young plants with smallroot systems. However, as thecrown tends to stay drier, risk ofcrown rot (phytophthora) may bereduced. You can’t use dripsystems for frost protection.

Drip irrigation systems com-monly are used in California inyoung plantings. At planting, oneemitter is placed near each plant.The second year, two emitters areplaced 12–18 inches from the

Establishing Your Kiwifruit Vineyard

trunk, and the one near the trunk isremoved (to keep the trunkrelatively dry). When the plant is4 years old, two more emitters areadded 3 feet away from the trunk.

When plants are mature,California growers find it difficultto supply enough water with fouremitters per vine, so they addmore emitters or switch tominisprinklers. For larger vines,up to 10 emitters per vine may benecessary.

Minisprinkler systemsUnder-vine minisprinkler

systems, which produce a wettedarea of greater size, often arepreferred. In general, they wetmore soil than drip emitters do,are easy to install, and tend to plugless frequently than drip emitters.They can be used to replace dripsystems as vineyards age. Inyoung vineyards, however,minisprinklers tend to over-irrigate.

These sprinklers spray water ina 6- to 18-foot diameter circle.One full-turn minisprinkler pervine, located equidistant betweenvines, should be adequate inmature plantings.Generally, they areallowed to run 6, 8,or 12 hours, two tofour times perweek.

Impactsprinklers

Impact sprinklersalso are used in kiwifruitvineyards, especially in moremature plantings. They can beplaced over or under thecanopy.

Overhead sprinklers are best forfrost protection, but may spot ordiscolor the fruit when used insummer. They also may leachnutrients from the leaves andincrease incidence of fungusdiseases.

Some California growers use aT assembly on the sprinkler riserto switch from over-vine sprin-klers to under-vine sprinklers.They use the over-vine positionsfor frost protection (shoots in thespring, fruit in the fall) and switchto the under-vine position insummer. (Note that only fuzzykiwifruit are sensitive to fallfrosts, because hardy kiwifruitmature earlier.)

Impact systems work well if thecanopies aren’t in the way, butthey tend to use more water.Under-vine sprinklers should bebetween vines in order to reduceimpact on the trunk.

Frost protectionOver-canopy sprinklers can

provide 6 to 8°F frost protection,whereas under-vine impactsprinklers can provide about 2 to3°F protection. In California,5/16-inch sprinklers are used at a

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spacing of 30 x 40 feet (at 50 lb/inch pressure) to supply 0.1 inch/hour (50 gallons/acre/minute).Start sprinkler irrigation beforetemperatures fall below the criticallevel and continue until tempera-tures are above critical levels.

FertilizationIt is relatively easy to burn the

roots of kiwivines, so applyfertilizer cautiously. The followingrecommendations are based onHayward in California and NewZealand.

Fertilize young kiwifruit vinesmonthly with small amounts ofnitrogen. Ammonium nitrate andurea are good sources of nitrogenfor kiwifruit.

In the first year, apply no morethan 0.4 oz of actual N per plantper month in May, June, and July(total of 12 lb actual N/acre basedon 160 plants per acre). Spread thenitrogen in a circle 6 to 12 inchesfrom the base of the trunk.

In the year after planting, apply0.8 oz of N per plant per month inApril, May, June, and July (32 lbN/acre total). Spread the fertilizerin a ring about 12 to 36 inchesfrom the trunk.

Fertilize third- and fourth-yearplants with 2 to 3 oz of actual Nevery other month from Marchthrough July (60 to 90 lb N/acre).

You may liquid feed nitrogen toyoung plants on a 2-week tomonthly interval instead of usinggranular fertilizer.

Do not fertilize young plantswith liquid or granular forms ofnitrogen later than July. Latefertilization forces late vegetativegrowth that is very sensitive tocold injury. Once plants bear fruit,the crop load tends to suppresslate vegetative growth and reducerisk of fall frost damage.

Other nutrients may be added inspring either foliarly or to the soilsurface. Base applications onnutrient needs/analysis. Kiwifruitvines tend to take up a consider-able amount of phosphorus (P)and potassium (K). Test soil for Pand K prior to planting, andincorporate nutrients preplant ifnecessary. Do not use fertilizercontaining potassium chloride, askiwivines are very sensitive tochloride.

wires

6'

5-6'

Figure 1-A.—Standard T-bar trellis system for kiwifruit.

Figure 1-B.—Winged T-bar trellis system for kiwifruit.

wires

45° angle

5-6'

6'

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Establishing Your Kiwifruit Vineyard

TrellisKiwifruit vines are not self-

supporting; their size, vigor,longevity, and heavy crop loadmean they need a strong, perma-nent support structure.

Two main types of supportstructures or trellises are used incommercial kiwifruit production:the T-bar and the pergola.A pergola provides a single planeof canopy about 6 feet above theground. The T-bar trellis systemconsists of posts in rows with across arm at 6 feet high.

T-bars are less expensive toconstruct, less labor intensive,better suited to bee pollination,and they reduce the risk of botrytisinfection. However, pergolasystems tend to produce moreyield per acre, and the fruit areless susceptible to wind damage.Also, once the full canopy isestablished in a pergola, the shadereduces weed growth.

T-barA typical T-bar trellis consists

of posts with a 5- to 6-foot(depending on row width) longcross arm extending across eachpost (Figure 1-A). The kiwivinefruiting canes are tied to wires ontop of the cross arm.

Use pressure-treated 4–6 inchdiameter posts that are 8–9 feetlong spaced at 15–20 feet downthe row. Square posts are easier towork with. Drive posts 2 to 3 feetinto the ground. Use end posts that

are at least 6 inches in diameter,and drive them at an angle withthe top of the post leaning 1 footfrom perpendicular away from therow. Anchor the end posts well.

The top of the cross arm is6 feet above the ground. Crossarms usually are a 2 x 6 inchboard bolted into a cut notch onthe post. You can brace cross armsback to the post for addedstrength.

Run a wire down the row fromthe top middle and each side ofthe crossarms (Figure 1-A). Twoadditional wires can be added, onebetween the center and each endwire. Use galvanized, high-tensile,12-gauge wire for the vine sup-ports. Good wire tighteners areneeded to keep a strong tension onthe wires to support the vines andcrop.

A common modification of theT-bar is the winged T-bar, inwhich an additional wing and wireare added to each side of the T-barcross arm (Figure 1-B). Tyingdown a cane from the center wireonto the two wires pulls it into amore natural curve.

PergolaA pergola trellis is designed to

support a solid canopy of foliageand fruit (Figure 2). Wires notonly extend down the row, butalso are used as “cross arms”(more commonly than usingwood) running perpendicular tothe vine rows. The wires areplaced 1 to 3 feet apart.

Figure 2.—Pergola trellis system for kiwifruit.

horizontal stayassembly

tie-back assembly

6'

6'

6'

20'

10'

12

TrainingYoung Vines

Proper pruning during theestablishment years is necessary toestablish a well-formed permanentframework for the vine. Develop-ing or training young kiwifruitvines into a bilateral cordonallows for easier managementwhen the plants are mature.Kiwifruit produce a crop onshoots (fruiting laterals) that growfrom 1-year-old canes (last year’sgrowth). In the first few years, youtrain vines the same way for boththe pergola and the T-bar system.

Prune dormant kiwivines in lateDecember to mid-February in thePacific Northwest. Later pruningmay cause excessive sap flow.

First growing seasonThe main objective during the

planting year is to develop asingle, straight trunk. At planting,prune plants back to one or twobuds (above the graft union ingrafted plants) (Figure 3-A).

Once shoots start to grow,select one vigorous shoot to trainupward as the trunk. Place a stakebeside the shoot to facilitatetraining. String from the wire tothe stake can add support as well.Tie the shoot to the stake (not tootightly or you’ll girdle the shoot)

at frequent intervals to helpprevent breakage.

Do not allow the shoot to wraparound the stake. Concentrategrowth into this shoot by remov-ing suckers at the base of the vine(Figure 3-B).

Remove all basal lateral shootsthat break along the trunk. If themain shoot loses vigor and beginsto twist slightly, top the shoot andtrain up the strong new “leader”(Figure 3-C). Continue to train thetrunk until it’s 2 to 3 inches abovethe wire (Figure 3-D).

If the shoot reaches the wireearly in the season, you may try toform the cordons in the first year.To do so, top the shoot to about4 inches below the training wire toencourage lateral branch forma-tion. This forms a nice “Y” for thecordons. Select two shoots,growing in opposite directions,and train them along the centerwire to form the two main arms,called cordons (Figure 3-E).

Another option is to train thetrunk up one way along the wireand wait until the next season totrain a shoot the other way. Thisresults in cordons of unequal age,which may make managementmore difficult.

During the first dormantseason, head back the cordon(s) towood of 1/4 inch in diameter or

larger (Figure 3-E). If vines didnot have adequate growth to formcordons the first season, head thetrunk back about 2 inches belowthe trellis wire to force new budsearly the next season.

Second seasonThe objective in this season is

to develop two permanent cordonsfrom two strong shoots growing inopposite directions from the trunkalong the center wire. As eachcordon grows, hang it over thewire and wrap it every 18 to24 inches to ensure that it’ssecurely attached to the wire.

Retain lateral branches thatare produced along the cordonsat about 8- to 12-inch intervals(Figure 3-F). Carefully tie thesecanes to the outer trellis wires.Remove all others by summerpruning before they twist aroundthe shoots you want to keep.

In the dormant season, prunethe main cordons and the retainedlateral canes back to wood 1/4 inchin diameter or larger (Figure 3-F).The first crop will form on shootsfrom these canes in the third year.Pruning the canes during thedormant season encouragesfruiting the following year.Remove any suckers and newgrowth on the trunk (Figure 4).

13

Establishing Your Kiwifruit Vineyard

center wire

center wire

(A) (B) (C) (D)

(E) (F)

Figure 3.—Training a young kiwifruit vine.(A) Prune to two buds at planting.(B) Train one shoot as trunk, remove all others (Year 1).(C) Head back “trunk” as shoot growth at terminal loses vigor.(D) Continue to remove lateral shoots; let “trunk” grow beyond wire. Then head to just below wire.(E) Choose two shoots to form cordon, one each way on wire. Head back to 1⁄4-inch diameter in dormant season (Year 1).(F) Shows shoot growth Year 2. Pruning cuts in dormant season Year 2 are shown.

14

Third seasonContinue to extend the cordons,

if necessary, by training thestrongest shoots down the centerwire until they’re within about1 foot of the cordon of adjacentvines. Do not allow them to twisttightly around the wire, becausethis may restrict sap flow later.

Continue to train lateralbranches perpendicular to thecordons (Figure 4). Do not trainshoots along the outer wiresparallel to the cordon; they willcause too much competition forlight.

In the third year, concentrate ondeveloping the vine’s framework.Fruit will form on shoots pro-duced on last year’s growth

(Figure 4). Fruit in the third yearmay sunburn due to inadequatecanopy cover. Do not overcrop thevine. It may be a good idea toremove some of the fruit to divertmore energy into vegetativegrowth.

In the third dormant period,prune so that 15 to 20 well-spacedlateral canes remain on the vine,depending on vigor. Remove anysuckers or side growth on thetrunk.

The permanent vine structureshould be established by thefourth year. Future pruning willrenew fruiting canes and maintainthe vine framework and crop load.See “Maintaining Your KiwifruitVineyard” for diagrams/descrip-tions of pruning producing vines.

Training of vines to a T-bar andpergola system is similar. In apergola, the vines are grown asstraight, single trunks until theyreach the top of the structure. Asingle strong permanent leader(cordon) then is allowed to growin each direction along the mainwire.

To form the canopy of apergola, develop a system offruiting canes from the cordons atright angles to the wires. Fruitingcanes can be retained longer onpergolas and may be more perma-nent than on T-bars. Fruitinglaterals or shoots develop on thefruiting canes. It takes up to7 years to develop a full canopy ina pergola.

center wire

wires

wires

Figure 4.—Kiwifruit vine in third growing season during fruiting. Leaves not shown on right to simplify drawing.

15

needed for early season growthand fruit set in May–June. Asecond application of granular N,the remaining one-third, is recom-mended in May–June.

Plants should have good soilmoisture when they are fertilized.Irrigate first, wait 1 to 2 days, thenfertilize; or fertilize after a goodrainfall.

You can substitute liquidfertilizer applied through theirrigation system for dry fertilizer.When applying liquid fertilizerscontaining N, use about 10 lbof actual N in each applicationfrom April through July. Higherrates of liquid N, 20 lb per appli-cation, have injured roots onlighter soils.

Base fertilization with othernutrients on tissue and soil analy-sis. Critical levels for leaf samplestaken in late August in Californiaand for New Zealand are given inTable 2 (recommendations fromboth areas are combined). It is notknown if species differ in nutrientneeds or if critical levels vary byregion. However, these values canbe used as a guide.

Based on experience in NewZealand and California, growerstypically apply the following as amaintenance application:55 lb/acre phosphorus in Febru-ary–March; and 80–130 lb/acrepotassium split between Febru-ary–March, April, and May.

It is essential to maintainyour kiwifruit vineyardwell for optimum growthand productivity. Pruningprobably is the most

challenging aspect of vineyardmaintenance.

Most of the research andexperience on kiwifruit productionis with Actinidia deliciosa,particularly Hayward. Unfortu-nately, there is relatively littledirect experience with hardykiwifruit production. The follow-ing information should, however,provide a good starting point forproduction of hardy kiwifruit aswell as the fuzzy types.

FertilizationIt is relatively easy to burn the

roots of kiwivines, so applyfertilizer cautiously. When apply-ing granular N, be sure to broad-cast it over the entire root zonearea; concentrating it near thetrunk can burn roots. Leaf necrosisis a symptom of fertilizer rootburn.

Mature vines, of 5 to 7 yearsand older, use about 1 lb of actualnitrogen (N) per vine per year, orabout 190 lb N/acre/year (with15 x 15 foot rows).

Apply about two-thirds of thenitrogen in March at bud break asa broadcast application under thecanopy. This provides the nitrogen

B. Strik

Maintaining YourKiwifruit Vineyard

16

Maintain soil pH at about 6.0with lime application in the fall.

Kiwifruit seem to be sensitiveto chlorine, so avoid any fertilizerswith chloride.

IrrigationThe water a vine loses through

transpiration must be replaced byirrigation or rainfall. On a warmsummer day in California, mature,full-canopy kiwifruit vines cantranspire 7,000 to 8,000 gallons ofwater per acre per day. Transpira-tion occurs when leaves usecarbon dioxide to produce carbo-hydrates through photosynthesis.

Irrigation is necessary to keepvines growing and productive andto maximize fruit size. Waterstress can reduce fruit size, limitflower numbers (through reducingflower bud initiation), and causepremature fruit drop. Summerdrought can cause leaf drop andpremature fruit ripening in arguta;however, fruit ripen moreunevenly and are of poorer flavor.Severe drought also may causefall flowering, which reduces thefollowing year’s production.Maturity of wood also seems to bedelayed by drought, thus increas-ing risk of cold injury. However,too much water also may causeproduction problems.

Judging vine water needs isdifficult. At this time, it’s notknown whether irrigation require-ments in the Pacific Northwestdiffer from those in other regions.Based on information from BritishColumbia, Canada, vine water useranges from 25 to 35 gallons/vine/day (at 70 to 80°F).

Irrigation for frost protectionalso is necessary to protect youngshoots in spring and potentiallyfruit in fall. See “EstablishingYour Kiwifruit Vineyard” formore information.

PollinationFor fruit to be produced, male

and female vines must be presentin a block and must flower at thesame time. Male flowers produceviable pollen for only the first 2 to3 days after opening. However,female flowers are receptive topollen for 7 to 9 days after open-ing, even when the petals havestarted falling.

Pollination is extremely impor-tant in kiwifruit production. Largefruit contain 1,000 to 1,400 seeds(research on Hayward). If pollina-tion is poor, fruit will have inden-tations (narrow valleys) on oneside or be non-uniform in shape. Ifyou cut through these fruit, you’llfind no seeds in these areas.

Kiwifruit flowers are pollinatedmainly by insects, although windmay play a minor role. Honeybees are the main pollinator usedin kiwifruit vineyards.

Kiwifruit flowers do notproduce nectar and are relativelyunattractive to bees. About threeto four hives per acre are neededto adequately pollinate kiwifruit.Place these in the vineyard nosooner than 10 percent bloom ofthe female vines.

In some years, you may haveno male vines in flower as a resultof winter injury to male plants(they are less hardy than thefemales). In this case, no naturallyproduced pollen will be available.To get a crop, the females willhave to be pollinated artificially.Call your county Extension agentfor more information on sourcesof pollen and methods of artificialpollination.

Fruit ThinningFruit thinning, or removing

fruit after set, can be done toremove misshapen fruit that areunmarketable and to increase thesize of the remaining fruit. How-ever, it is doubtful whetherthinning is economical in kiwi-fruit. Usually, proper dormantseason pruning balances the cropload. Also, there’s evidence that inHayward the yield loss due to fruitthinning is not compensated for byincreased size of remaining fruit.

Table 2.—Kiwifruit leaf sufficiency levels for nutrients.

Nutrient % dry weight Nutrient ppm

Calcium 2.0–4.0 Boron 25–200Magnesium 0.20–0.80 Copper 5–15Nitrogen 2.0–2.8 Iron 60–200Phosphorus 0.13–0.30 Manganese 50–200Potassium 1.5–2.5 Zinc 15–30Sulfur 0.15–0.45

17

Pruning and TrainingProper pruning is necessary for

several reasons:

• To establish and maintain awell-formed permanent frame-work for the vine

• To obtain a balance betweenvegetative growth and fruitproduction

• To develop a canopy that usesavailable light efficiently (forphotosynthesis), yet is openenough to obtain maximumfruit quality and flower budformation for next year’s crop.An open canopy also facilitatesharvest and reduces risk offungal diseases such as botrytis.

All species of kiwifruit can bepruned in a similar manner.However, there are many differentways to prune a kiwivine. Thefollowing description covers thebasic techniques. Grower experi-ence may lead to modifications.

Dormant pruningDormant pruning of kiwivines

is best done in late December tomid-February in the PacificNorthwest. Late-pruned vines mayhave excessive sap flow.

In kiwifruit, flowers are pro-duced on current season shootsthat grow from buds developed on1-year-old canes (last year’sgrowth). Shoots that grow fromolder wood seldom produce fruitin their first season. Shoots frombuds that were heavily shadedduring the preceding season willbe less productive than those frombuds that were exposed to the sun.

Ideal 1-year-old canes haveshort internodes with well-formedbuds, and stop growing early inthe season. These canes develop

early in the growing season.Fruiting laterals are currentseason’s shoots that have fruit onthe basal nodes (4 to 6 buds); allthe buds beyond the fruit arecapable of producing flower budsfor next year’s crop.

Male and female plants shouldbe pruned differently whenmature.

Female vines. When pruning amature vine, remove about70 percent of the wood that grewlast season. Most of the woodremoved is older wood thatalready has fruited. New fruitingcanes usually will have developedat the base of last year’s canes.Figure 5 shows a typical fruiting

cane that developed from thepermanent cordon.

Replacement fruiting canes thatoriginate from the cordon may beleft to replace older wood in thefuture. Fruiting canes should beseparated by about 8 to 12 incheson the cordon. Head back replace-ment fruiting canes to forcegrowth next season, and tie themto the wires for support. Do not tiecanes too tightly or they’ll girdleduring the growing season.

Spurs (shorter fruiting brancheswith short internodes) oftenoriginate from the older wood. Donot remove them unless absolutelynecessary, as they are very fruitful(Figure 5).

Maintaining Your Kiwifruit Vineyard

cordon

fruitful shoot

Figure 5.—Mature portion of a kiwifruit cordon in production. Leaves are notdrawn to simplify the figure. Fruit are produced on shoots growing from lastyear’s growth. Winter pruning cuts are shown by .

fruitful cane (heading cut madeprevious winter)

winter pruning cut

spur

replacement cane(headed backin winter)

18

Remove most of the older woodback nearly to the cordon. Whennecessary, you can leave somesecond-year canes for fruitingwood if 18–48 inches of newgrowth is present beyond wherefruit was formed last season(Figure 6). Head back thesefruiting laterals to 2 to 4 buds infuzzy kiwifruit and to 8 to 12 budsin hardy kiwifruit beyond wherefruit was formed last year.

Take care that 1-, 2-, andsometimes 3-year-old fruitingcanes are evenly distributed on thetrellis to avoid overcrowding inany area of the canopy.

Remove twisted and tangledgrowth, shoots that cross from oneside of the vine to the other, andwind- or winter-damaged shoots.Mature vines, spaced at 15 feet inthe row, should have 30 to 45fruiting canes per vine (spaced at8 to 12 inches on both sides).

Male vines. The goal whenpruning male vines is to produceas many flowers for pollination aspossible, while keeping the vinemanageable. One popular way toprune male vines is to cut most ofthe canes back to 6 to 12 inches assoon as flowering is finished. Newgrowth during the summer will besufficient to produce flowers fornext year. If needed, you can trimthe vine during the dormantseason.

Summer pruningIn New Zealand, summer

pruning begins in mid-springbefore flowers open. Removeshoots without flowers thatoriginate outside of the wires(T-bar system). Cut back flower-ing laterals to four to six leaves

beyond the last flower. Cut backwatersprouts (vigorous shootsfrom older wood), and remove anytangles. During the summer,vegetative growth can be veryvigorous. Remove shoots notwanted the following year forreplacement canes and tip replace-ment canes to prevent tangling.

Figure 6.—Dormant portion of a mature kiwifruit vine cordon. Winter pruningcuts are shown by . Shoots labeled with an “F” fruited last season.

In California, more summerpruning is done on the pergolathan the T-bar training system.However, take care not to exces-sively summer prune as fruit andsometimes canes may becomesunburned.

Remove all suckers or shootsthat grow from the trunk duringthe growing season.

spur

cordon

replacementcane

replacement cane

F

F

F FF

F

F

FFF

F

19

in 4 to 6 days if held at 68–77°F(20–25°C) in an ethylene environ-ment.

A decline in starch content asfruit mature is coupled with anincrease in percent soluble solids(sugars). The increase in solublesugars that begins as kiwifruitapproach maturity continues afterharvest and peaks about whenstarch hydrolysis is complete. Asfruit mature on the plant, part ofthe increase in sugars occurs asthe plant produces more carbohy-drate through photosynthesis.

With advancing maturity, theaccumulation of carbohydrateslows, yet the sugar contentcontinues to increase. At thispoint, the increase in sugarsprimarily is due to the conversionof stored carbohydrates (mainlystarch) to sugars. Kiwifruitcontain lots of glucose andfructose and a small amount ofsucrose.

At the peak of carbohydrateaccumulation, fruit have essen-tially achieved their best potentialeating quality, and further delaysin harvest will not improve flavor.

Fruit size within a vine is notrelated to fruit maturity. Also,most cultivars show little visualchange in fruit appearance as theymature. For these reasons, it isunreasonable to attempt multiple

B. Strik

Harvest, Handling,and Storage of Kiwifruit

Most of theresearch onharvest,handling, andstorage of

kiwifruit has been done with themost common kiwifruit growncommercially, Hayward (Actinidiadeliciosa).

Although there is a great dealof interest in growing hardykiwifruit (A. arguta) commerciallyin the Pacific Northwest, verylittle information is availablespecific to this species. Most ofthe following information relatesto the fuzzy kiwi, Hayward.However, where information onhardy kiwifruit is available,differences are noted.

Fruit MaturationKiwifruit continue to increase

in fresh weight and size untilharvested, but the most rapid sizeincrease occurs the first 100 daysafter bloom. Kiwifruit are one of

the few fruits that retain ahigh starch content atmaturity.

Starch hydrolysis,or breakdown,continues afterharvest, even at

32°F, and is essentiallycompleted within a few weeks

after harvest. Freshly harvestedkiwifruit can be cleared of starch

20

harvests from a vine. Haywardtends to have more uniformripening of fruit within a vine thando the arguta cultivars(Ananasnaya, for example).

Soluble solids (sugar) content(°Brix) is the most commonlyused maturity index for kiwifruit.In California, Hayward areharvested at a 6.5 percent solublesolids standard (6.5 °Brix). Fruitthen will attain good quality instorage. Soluble solids content isabout 12 to 18 percent when ripe.

In the arguta cultivars, fruit areat about 18 to 25 percent solublesolids when ripe. However, toincrease shelf life and facilitateharvest, this species of kiwifruit isharvested between 8 and 9 °Brixwhen fruit are very firm.

The soluble solids content ofkiwifruit can be measured with ahand-held refractometer. Cut awedge extending from the stem toblossom end of the fruit andsqueeze the juice from the fruit.

Starch in unripe kiwifruit willcloud the solution and makerefractometer readings difficult.Pour the sample through a fewlayers of facial tissue to clear thesolution. For a non-temperature-corrected refractometer, follow thedirections for accurate °Brixreadings carefully.

A sample of kiwifruit can beripened fairly easily to monitorripe fruit soluble solids content,but this takes several days. Toripen small samples, place fruitwith fresh apples to provide asource of ethylene. At 77°F(25°C), ripening will take 4 to5 days.

HarvestingOnce the minimum maturity

standards have been achieved, allof the fruit can be harvested in onepicking. Harvest fruit by hand. Toharvest fuzzy kiwifruit, pickersshould wear soft cotton gloves toprevent damage to the skin (fuzz)of the fruit. Fruit are easilydamaged by rough handling eventhough they seem quite hard atthis stage of maturity.

If arguta fruit are too vine ripeor soft, fruit will tear at the stemend. This is not a problem whenharvesting at 8 to 9 °Brix and fruitare hard. Do not harvest prema-turely softened fruit, as their shelflife is very poor.

Keep fruit in the shade whileawaiting transport, and cool themas quickly as possible to maximizestorage. Field heat must beremoved quickly from fruit afterharvest, because the fruit can losewater quickly. After 3 to 4 percentwater loss, fruit may appearshriveled, especially at the stemend. This is less of a problem withA. deliciosa in the Pacific North-west (compared to California),because fruit are harvested inOctober.

Softening of kiwifruit also istemperature-dependent—fruit at41°F (5°C) soften three timesfaster than fruit at 32°F (0°C).Avoid exposing fruit to ethylene, agas that promotes ripening andfruit softening.

Fruit usually are sorted for sizeand quality before packing. If fruitare not packed immediately, storethem in large bins.

StorageStore kiwifruit as near to 32°F

(0°C) as possible at 90 to95 percent relative humidity. Evenwhen fruit are held at this tem-perature, about one-third toone-half of the remaining fleshfirmness may be lost per month ofstorage in Hayward. Fruit aresensitive to freezing injury; becareful that the temperature of thefruit does not drop below 32°F.

For long-term storage, use ofcontrolled atmosphere (5 percentCO

2; 2 percent O

2) has been

effective in Hayward, providedtemperature is kept at 32°F andethylene-free atmospheres aremaintained. Note that only bat-tery-operated forklifts should beused in storage rooms to avoidgenerating ethylene. Monitorlevels of ethylene in storage on aregular basis, because a week ormore of 10 ppb ethylene willhasten fruit softening.

Hayward fruit can be stored 3 to6 months under ideal storageconditions. Arguta or hardykiwifruit, however, cannot bestored as long, because fruit aremore perishable.

To optimize shelf life of argutafruit (e.g., Ananasnaya), harvest at8 to 9 °Brix, handle fruit carefullyto avoid bruising, immediatelycool fruit to 32°F, and store themat 95 percent relative humidity.Fruit should keep for up to2 months under these conditionsand can be ripened with ethylene.

© 1998 Oregon State University

Pacific Northwest Extension publications are jointly produced by the three Pacific Northwest states—Oregon, Washington, and Idaho. Similar crops,climate, and topography create a natural geographic unit that crosses state lines. Since 1949 the PNW program has published more than 500 titles. Jointwriting, editing, and production have prevented duplication of effort, broadened the availability of faculty specialists, and substantially reduced the costs forparticipating states.

Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the Oregon State University Extension Service, WashingtonState University Cooperative Extension, the University of Idaho Cooperative Extension System, and the U.S. Department of Agriculture cooperating.

The three participating Extension Services offer educational programs, activities, and materials—without regard to race, color, religion, sex, sexualorientation, national origin, age, marital status, disability, and disabled veteran or Vietnam-era veteran status—as required by Title VI of the Civil RightsAct of 1964, Title IX of the Education Amendments of 1972, and Section 504 of the Rehabilitation Act of 1973. The Oregon State University ExtensionService, Washington State University Cooperative Extension, and the University of Idaho Cooperative Extension System are Equal Opportunity Employers.Published February 1998 (replaces Oregon publication EC 1464). Reprinted September 2000. $2.50

© 1998 Oregon State University

Pacific Northwest Extension publications are jointly produced by the three Pacific Northwest states—Oregon, Washington, and Idaho. Similar crops,climate, and topography create a natural geographic unit that crosses state lines. Since 1949 the PNW program has published more than 500 titles. Jointwriting, editing, and production have prevented duplication of effort, broadened the availability of faculty specialists, and substantially reduced the costs forparticipating states.

Published and distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914, by the Oregon State University Extension Service, WashingtonState University Cooperative Extension, the University of Idaho Cooperative Extension System, and the U.S. Department of Agriculture cooperating.

The three participating Extension Services offer educational programs, activities, and materials—without regard to race, color, religion, sex, sexualorientation, national origin, age, marital status, disability, and disabled veteran or Vietnam-era veteran status—as required by Title VI of the Civil RightsAct of 1964, Title IX of the Education Amendments of 1972, and Section 504 of the Rehabilitation Act of 1973. The Oregon State University ExtensionService, Washington State University Cooperative Extension, and the University of Idaho Cooperative Extension System are Equal Opportunity Employers.Published February 1998 (replaces Oregon publication EC 1464). Reprinted September 2000. $2.50

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