My rule of thumb is to cover plants if the temp. is expected to be below 50 degrees F. I have heard that some growers do not cover plants until it gets below 40, and still others claim they do not cover unless there is a frost.
wait! It's sunny again… wait… ), but some vegetables won't be happy (and grow into incredibly prolific tomato producers - yes, I'm talking to you, tomato fanatics) if you don't protect them until night temperatures warm up consistently to 50 degrees and above.
At temperatures below 40°F, tomato plants will begin to wilt and brown from chilling injury. At best, the plant will experience stunting, wilting, and pitting of fruit.
How much cold can tomatoes tolerate in the fall weather? Covering tomatoes usually provides adequate protection from frost and light freezes. However, the foliage and fruit will likely suffer damage should the overnight temperature fall to 28 degrees F (-2.2 C) or below for several hours.
However, warm-season vegetables such as peppers, tomatoes, cucumbers, melons and squash can be damaged if the temperature drops to 33 F. Consider these tips to help protect your plants as temperatures drop.
Most houseplants are native to tropical areas and will not tolerate freezing temperatures. Many indoor plants will see damage when temperatures drop to the mid to lower 40s°F and nearly all will die if exposed to below freezing temperatures.
You might think of peppers as annuals if you're growing anywhere other than a tropical or subtropical climate. That's because peppers can't handle freezing temperatures.
Another temperature to keep in mind: tomato plants will not survive in temperatures below 35 degrees Fahrenheit, and will not thrive at temperatures below 50 degrees. Gardeners can use a frost date calendar to note their region's average dates of last frost in spring and first frost in fall.
Covering plant material at temperatures between 39-30 with freeze cloth or covering can be effective. Prolonged exposure at temperatures of 28 degrees and below will notice protection results diminish with each degree dropped.
Even prolonged exposure to temperatures below 55 degrees F. (13 C.) can cause decay, pitting, and water-soaked areas on fruit. Sudden cold snaps can cause cucumber plant damage on leaves, stems, and fruit or even kill the plants.
Depending on where you live, you might want to expose your tomatoes to morning sunlight, to afternoon sunlight, or to a combination of the two. Morning sunlight provides high-intensity light without excessive heat, therefore you should consider morning exposure if you live in a region with a hot climate.
Q: Can frost occur at temperatures above 32°F? A1: No, frost is defined as a layer of ice that forms on surfaces that are at or below 32°F.
Covering potato plants with fresh, rich, loose organic material like this can continue until the hill is as tall as you can or want to make it. Ideally, the taller the hill, the more potatoes you will get. Unfortunately, rain and wind can erode these potato hills if they are left exposed.
Each plant has a different threshold when it comes to dealing with the cold. Some plants can survive outside even when temperatures hit freezing. Others need to be brought indoors when temperatures reach the mid-40s.
Marigolds can handle a bit of a chill, but they draw the line at frost. They can survive down to about 40°F, but it's not a party they enjoy. To prepare for cooler nights, especially in the unpredictable shoulder seasons of spring and fall, think like a marigold.
Cover Plants – Protect plants from all but the hardest freeze (28°F for five hours) by covering them with sheets, towels, blankets, cardboard or a tarp. You can also invert baskets, coolers or any container with a solid bottom over plants. Cover plants before dark to trap warmer air.
So when temperatures start dipping below 50º F, leave the tomatoes on the vine if warmer days and nights are forecast. But if temperatures have started on a steady downward slide, go ahead and pick the mature green tomatoes and bring them indoors.
Fabric is a better choice because it will let moisture out while holding onto some heat from the earth. You could also cover the plants with buckets or storage totes and place hot water bottles near them. Also, my sympathies for the late frost.
Tomato seedlings suffer cold damage in temperatures below 60 degrees Fahrenheit. Some tomato varieties are bred to be more cold-tolerant and can set fruit when it's below 55 degrees Fahrenheit.
Tomatoes growing in pots have high water needs. The relatively small soil volume in the container limits the amount of water available to plants. During the heat of summer, container-grown tomatoes often need to be watered daily. Hot, windy conditions might require twice daily watering.