Managing the Greenhouse Environment: Temperature, Humidity and Water

Rob Eddy, Plant Growth Facilities Manager

Purdue University, HLA Department

West Lafayette, IN

Take Home

· Test water

· Consider computer environment control

· Test water

· Consider automating irrigation

· Test Water

Temperature

· Regulates germination, growth, flowering, fruiting, longevity

· Optimum temp is species dependent

· 75/65 F generally

· Night drop is important

· Multiple stages of heating and cooling improves control

· A weather station greatly improves environment control and saves programming time

· Alarming with an autodialer. Requires a phone line.

Humidity Control

• 50-90% RH generally
• Plants, wet soils and floors provide humidity.
• Mostly worry about disease promotion.

• Vent or heat or both if condensation lingers on glass past mid-morning
• Pre-dawn venting
• Keep the air moving

Watering

· Quality--test clear water before growing your first plant. Direct yourself to do it regularly for clear water and fertilizer.

· Quantity--can’t overwater plants by putting on too much water at one time

· Frequency--depends on weather, pot, soil, species, age

· Application method--should be automated whenever possible

· Spot watering vs. crop watering

· Hand watering vs. automation

· Clock automation vs. computer automation

Resources

· Text: Greenhouse Operation and Management by Paul V. Nelson

· Trade pubs: GrowerTalks, Greenhouse Grower

· Free greenhouse bulletins available at flowers.hort.purdue.edu

· Rob at 765-496-3710 or eddy@hort.purdue.edu