6TemperatureTemperature can influence some diseases and insect problemsTemperature influences quality of most fruits and vegetablesMost plants will not grow below 40°F or above 96°F
7Temperature Cool season crops Day temperatures 60 - 75°F Night temperatures °FTolerate some frostSpinach – Radish – CarrotsCabbage – Beets – OnionsLettuce – Peas
8Temperature Warm season crops Day temperatures 70 - 85°F Night temperatures °FUsually do not tolerate frostShould not be planted until the ground warmsCorn – TomatoesBeans – Vine crops
9Temperature Photosynthesis Respiration Therefore: CO2 + H2O C6H12O6 + O2RespirationC6H12O6 + O2 CO2 + H2OTherefore:Photosynthesis leads to an increase in growth and storageRespiration leads to a decrease in storage and reduced growth
10Temperature Growth and plant yield = P - R During the day, both photosynthesis & respiration take place but at night, only respiration takes placeBest to keep temperatures warm during the day and cool at night!Respiration increases more than photosynthesis at high temperatures
11photosynthesisRelative ratesrespiration40°F °FSugars burned up as fast as made. No net growthToo coldfor growth
12Temperature Heat units Growing Degree Unit = Mean temperature - Base temperatureBase = either 40 or 50 depending on crop
13Heat units (example)* if mean is less than base, enter “0”
14Temperature Uses of Heat Units: Predict time to harvest Peas ‘Accord’ takes 1150 GDU‘Nugget’ takes 1570 GDU‘Alderman’ takes 1700 GDUCorn‘Aztec’ takes 1330 GDU‘Butter and Sugar’ takes 1570 GDU
15Temperature Uses of Heat Units: (continued) Predict flowering date Predict certain pest problemsDetermine if a crop will grow in a certain area!
16PhenologyPhenologyRelating the development of one plant to some aspect of anotherGreek for “the science of appearances”
17PhenologyLilacWhen in flower, time to plant tomatoes
18PhenologyForsythia RoseWhen in flower, time to prune your roses!