Use your handy dandy soil thermometer to check the soil and make sure it is falling in the optimum range. Depending on the particular plant in question, set the greenhouse thermostat to a temperature … This will give the tomato plant adequate time to mature before fruiting. The plants stop growing below 8-10 °C and the temperatures above 32 °C (90 degrees) cause floral abortion and poor fruit setting. Tomatoes are slow to ripen if temperatures are too cold or too hot. When tomato plants reach around 35C they stop growing and the same is true when temperatures are much below 10C depending on the variety. Tomatoes thrive when grown in temperatures that range between 70 … Tomato plants tolerate temperatures that are less than 55 degrees and over 100 degrees Fahrenheit, but after a few days of extreme to low or high temperatures, the plant will experience blossom drop. pre. The Effect of Extreme Temperatures on the Tomato and Pepper Crop Freezing and chilling injury in tomato and pepper plants. Temperature for Tomato Germination. Humidity combined with low temperatures also has an influence on growth where condensation is high – see transpiration. Nutrient deficiency symptoms, primarily from the lack of taking up phosphorus, start to appear at temperatures below 60°F (16°C). When the heat is on, tomato plants take a break: they don’t care for excessive heat any more than the rest of us. In the meantime, put the trays on a grow mat or a warm space such as the top of the refrigerator. The ideal temperature for tomatoes to ripen is between 68° - 78° degrees Fahrenheit or 20° - 26° degrees Celsius. The favorable range to grow tomatoes is between 70 and 79 degrees Fahrenheit ( 21 – 26 °C) with full exposure of sunlight. At medium temperatures, between 50 and 68 degrees Fahrenheit, or 10 and 20 degrees Celsius, the photosynthetic enzymes work at their optimum levels, so photosynthesis rates gauge high. The main factor that may cause a problem is the tomato growing temperature. A soil thermometer can help you decide when to plant tomatoes. Although frost occurs, by definition, when the temperature drops to 0 ° C at 1.5 meters above the ground, this may or may not result in freeze damage to crops. However, optimal temperatures vary somewhat with the growth stage of the plant. The ideal soil temperature for planting tomatoes is 60 degrees Fahrenheit or 16 degrees Celsius. ... A lot of tomato varieties refuse to produce fruit crops when temperatures are below 50 degrees Fahrenheit or 10 degrees Celsius. Continue to monitor the temperature of the soil and make sure it stays moist. After everything has stabilized, plant your seeds. It will also fail to produce fruits with temperatures as high as 90 degrees Fahrenheit or 32 degrees Celsius. The roots of cultivated tomato cease to grow at 10 degrees Celsius, and growth is slow to recover after rewarming (Scott and Jones 1986).” “Chilling the roots of the cultivated tomato damages ammonium influx, but not nitrate uptake or ammonium efflux (Bloom et al. 1998). The Ideal Soil Temperature for Tomatoes. A good example of this is the tomato. At temperatures above 86°F (30°C) lycopene, the red pigment in tomatoes, does not form and fruit do not color properly.2 Too much sunlight will cause the tops of the tomatoes to overheat, leading to green or yellow shoulders on the fruit. The night temperatures of 13-18 °C (58-65 degrees Fahrenheit) encourage the fruit set. In some cases the germination temperature is higher than is ideal for growing. The ideal temperature for tomatoes to ripen is 70 to 75 degrees Fahrenheit (21 to 24 degrees Celsius). If you are experiencing a particularly cool or scorching hot summer the natural ripening process can be severely impacted or even halted if the temperatures stray from ideal for extended periods of time.