1. Temperature

2. Temperature Plant processes influenced: Photosynthesis Respiration
Enzyme activity
Transpiration
Stomatal opening
Pollination
Seed germination

3. Temperature
This factor, more than any other, determines what plants can be grown in a particular area

4. Temperature
Temperature affects the maturity rate of garden products

6. Temperature
Temperature can influence some diseases and insect problems
Temperature influences quality of most fruits and vegetables
Most plants will not grow below 40°F or above 96°F

7. Temperature Cool season crops Day temperatures 60 - 75°F
Night temperatures °F
Tolerate some frost
Spinach – Radish – Carrots
Cabbage – Beets – Onions
Lettuce – Peas

8. Temperature Warm season crops Day temperatures 70 - 85°F
Night temperatures °F
Usually do not tolerate frost
Should not be planted until the ground warms
Corn – Tomatoes
Beans – Vine crops

9. Temperature Photosynthesis Respiration Therefore:
CO2 + H2O C6H12O6 + O2
Respiration
C6H12O6 + O2 CO2 + H2O
Therefore:
Photosynthesis leads to an increase in growth and storage
Respiration leads to a decrease in storage and reduced growth

10. Temperature Growth and plant yield = P - R
During the day, both photosynthesis & respiration take place but at night, only respiration takes place
Best to keep temperatures warm during the day and cool at night!
Respiration increases more than photosynthesis at high temperatures

11. photosynthesis
Relative rates
respiration
40°F °F
Sugars burned up as fast as made. No net growth
Too cold
for growth

12. Temperature Heat units Growing Degree Unit =
Mean temperature - Base temperature
Base = either 40 or 50 depending on crop

13. Heat units (example)
* if mean is less than base, enter “0”

14. Temperature Uses of Heat Units: Predict time to harvest Peas
‘Accord’ takes 1150 GDU
‘Nugget’ takes 1570 GDU
‘Alderman’ takes 1700 GDU
Corn
‘Aztec’ takes 1330 GDU
‘Butter and Sugar’ takes 1570 GDU

15. Temperature Uses of Heat Units: (continued) Predict flowering date
Predict certain pest problems
Determine if a crop will grow in a certain area!

16. Phenology
Phenology
Relating the development of one plant to some aspect of another
Greek for “the science of appearances”

17. Phenology
Lilac
When in flower, time to plant tomatoes

18. Phenology
Forsythia Rose
When in flower, time to prune your roses!

19. Winter temperatures Winter injury often occurs from:
Intercellular ice formation (between cells)
Intracellular ice formation (within cells)

20. Winter temperatures Factors that influence hardiness:
Kind of plant (ex: apple vs. peach)
Temperature during autumn
Soil moisture
Light
Nutrition

21. Hardiness curve (degree of hardiness attained)
High
Hardiness attained
Low
A S O N D J F M A M J J
Months

22. Winter temperatures Minimum temperature and when it occurs
Rate of freezing
Length of time frozen
Number of times frozen
Amount of snow cover
Wind

23. Winter temperatures Symptoms of winter injury Dead flower buds
Dieback of shoots
Brown needles
Bark splits (common on Norway maple)
Sunscald
Root injury/low vigor
Frost heaving

24. Winter damage
catfacing

25. Winter damage
Bark split
Fungi

26. Winter injury
Winter injury is often associated with a particular set of conditions:
Plants grow too late in the fall (Japanese maple)

27. Winter injury Extreme cold too early in fall or winter Drying winds
Mid-winter warm period followed by severe cold
Lack of snow cover

28. Winter damage
Snow line