temperature, humidity and environment04.pdftext: greenhouse operation and management by paul v....
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Managing the GreenhouseEnvironment:
Temperature, Humidity andWater
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
Figure 3. Effect of changing heat stages on temperature uniformity. At 15:00, program change was made to this zone monitored but not controlled by Priva
Computers, improving uniformity.
3 0
3 4
3 8
4 2
4 6
5 0
5 4
5 8
6 2
6 6
7 0
7 4
7 8
8 2
8 6
9 0
0:00
2:00
4:00
6:00
8:00
10:0
0
12:0
0
14:0
0
16:0
0
18:0
0
20:0
0
22:0
0
23:5
9
Time of day
Tem
pera
ture
(F)
Measured Zone Temp Calc Heating Temp Calc Cooling Temp
Multiple stages of heating and cooling improves control
A weather station greatly improves environment controland saves programming time.
Alarming with an autodialer. Requires aphone line.
•50-90% RH generally
•Plants, wet soils and floorsprovide humidity.
•Mostly worry aboutdisease promotion.
•Vent or heat or both ifcondensation lingers onglass past mid-morning.
•Pre-dawn venting
Humidity Control
Keep the air moving
Watering
• Quality--test clear water before growingyour first plant. Direct yourself to do itregularly for clear water and fertilizer.
• Quantity--can’t overwater plants by puttingon too much water at one time
• Frequency--depends on weather, pot, soil,species, age
• Application method--should be automatedwhenever possible
Application Method
• Spot watering vs. crop watering
• Hand watering vs. automation
• Clock automation vs. computerautomation
Solenoids and
timers
Drippers andsprinkler heads
Resources
• Text: Greenhouse Operation andManagement by Paul V. Nelson
• Trade pubs: GrowerTalks, GreenhouseGrower
• Free greenhouse bulletins available atwww.flowers.hort.purdue.edu
• Rob at 765-496-3710 [email protected]
Take Home
• Test water
• Consider computer environment control
• Test water
• Consider automating irrigation
• Test Water
Have a nice crop!