Growing Greenhouse Crops

What Type of Plants Can One Grow in a Greenhouse?

• Trees?• Shrubs?• Bulbs• Herbacious?• Perenials?• Annuals• Grass?• Food?• Cut flowers?

What are the Limiting Factors in a Greenhouse?

• Cost?

• Space?

• Seasons?

Types of Greenhouses

Cold Frame

Lean to Greenhouse

Topics

• Greenhouse Environment• Containers• Media• Irrigation• Fertilzation• Controlling Plant Growth• Managing Pests• Schedule• Specific Plants

Environment

• Temperature 55 to 65 degrees with 10-15 degrees warmer during the day is critical for most plants.

• Thermotropism: Plants growth in response to temperature

• Thermoperiodic: Flowering due to temperature

Environment Continued

• Light: Maximum intensity must be achieved with sun and lights.

• Light Duration: Some plants respond to day length for growth cylcles.

• Photoperiodism: Plants flower due to day length. Short day plants flower when days are short (less than 12 hours).

Environment Continued

• Air: One must have air flow. You can increase CO2 levels with machines.

• Humidity: High humidity is good for plant growth but can increase disease levels.

Containers

• There are different containers for all different types of plants.

Growing Media

• Well drained

• Good Moisture holding capacity

• pH of 5.5-6.5 (slightly acidic)

• Good support

• Common ingredients include perlite, sand, vermiculite, bark, and peat moss.

Irrigation (Watering)

• Drainage: Medium and pot must be well drained

• Timing: Water just before plants show signs of water deficiency

• Amount: The entire medium surrounding the roots must be wet. The only way to ensure this is to have water come out of the bottom

Watering Continued

• Water in morning.

• Don’t get foliage wet if possible.

• Types of watering include hand watering, spaghetti tube, drip, ebb and flood, and capillary mat system, overhead, perimeter, and soaker hose system.

• Dissolved chemicals such as flouride or cholorine can be harmful to plants.

Fertilizers

Organic Fertilizer: Natural derived from living things such as manure, blood and bone material.

Inorganic: Synthetic nutrient compounds made by humans. These are most often used in greenhouse crops

Application methods: Injection (through the irrigation lines, solids (top dressed or mixed with the soil.)

Controlling Plant Growth

• Pinching: Pinching off the unwanted material to create desired growth.

Controlling Plant Growth Continued(Growth Regulators)

• Hormones– Auxins: rooting hormones– Gibberellic acid: flower growth/elongates

growth– Ethephon: flower growth– Height retardents: shorten stems– Chemical pinching agents: promote branching

Integrated Pest Management in a Greenhouse

• Prevent entrance of pests: inspect new plants.• Weed control: they can harbor disease and

compete for nutrients• Sanitation: Keep it clean• Crop inspection• Environmental manipulation: give the plant the

right conditions so that pests can’t live.• Pest eradication: Pesticides/biological control

Scheduling Plant Growth

• All plants have specific schedule to get desired crop at the right time.

• Temp

• Light intensity and day length

• Seasons