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.
What is your critical low temp. for covering tomatoes? 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.
People have asked, can peppers survive 40˚ F temperatures? Most peppers are not happy when temperatures drop below 50-60˚ F.
Some plants can survive outside even when temperatures hit freezing. Others need to be brought indoors when temperatures reach the mid-40s. Be sure you know this before you plant.
Tomatoes need to be kept well above freezing to survive. There's no point trying to put them outside – or even into a greenhouse – until your last expected frost date has safely passed. Temperatures below 10ºC (50ºF) can result in slow growth and problems with flowering and fruiting.
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.
Frost Hardy
Root crops develop more sugars when the soil temperature is below 40 degrees Fahrenheit; and Brussels sprouts are often best after a light freeze. Among the hardiest vegetables are cole crops, which can tolerate moderate freezes (24 to 28 degrees Fahrenheit) : Broccoli, cauliflower (26 degrees Fahrenheit)
Fruit that sets when temperatures average above 80°F may be small and poorly shaped due to heat injury to the blossoms. Temperatures below 60°F at night will also result in blossom drop. At temperatures below 40°F, peppers may show some chilling injury.
Plan to bring in your houseplants when temperatures are forecast below 45 degrees F to protect them from stress and cold damage. Tender perennial herbs like Rosemary or Lemon Verbena can be brought indoors as well for winter cooking.
First, it's good to know which plants are sensitive to temps around 35 or 40 degrees F. These are common tender plants that will need some protection. Hanging baskets: begonias, calibrachoa, gerbera, impatiens, vinca, euphorbia, and scoparia.
Cucumbers are heat-sensitive and do best in temperatures between 60-90°F (16-32°C). They can tolerate some heat but will become stressed if temperatures exceed 95°F (35°C). Cucumbers can also be damaged by frost and temperatures below 50°F (10°C).
The fact of the matter is that YES the plants are related and YES they share some common diseases but most people do not have the space in their garden to separate them. The reality is that because the two have similar growth requirements, they can in fact be grown quite successfully together.
Tomatoes are a summer-season vegetable and are usually grown as summer annuals. Tomato seeds must be started indoors between March to June.
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.
The plants grow quite tall in summer and I often notice bunches of green tomatoes that I know won't ripen in time. That's when I cut the top off the tomato plants. This is a great way to keep the plant from growing even larger and instead ripening the fruits. I cut them when they grow to around my shoulder.
Once temperatures drop below 40°F, you may want to start covering your plants with a frost blanket depending on what you're growing, which we'll get into in just a bit. Freeze – A freeze is when the air temperature is 32°F or below.
You can preserve summer tomatoes by bringing 'outdoor' plants inside at the end of summer to save them over the winter. Older plants will gradually stop producing, so you can't save them forever, but it's possible to at least extend the harvest. However, you can also harvest indoor tomatoes throughout the year.
Plants need to be transitioned indoors before the outside temperature starts dropping below 45 degrees Fahrenheit (7 degrees Celsius) at night.
How Cold Can Tomatoes Tolerate? Tomato seeds won't germinate when the soil temperature is below 50 degrees Fahrenheit. 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.
H2 Rating - 34 to 41° F (1 to 5 C)
Overall, these annuals are the most delicate of all the hardy annuals - one might call them half-hardy since they are really only hardy into the few temperatures just above freezing. And it's important to NOT let them freeze.
Tomato plants can suffer from chilling injuries when temperatures are between 0 °C to 5 °C . Pepper plants can also suffer from chilling injury if temperatures stay between 0 to 10 °C (32 to 50 °F ) for a long time. This injury may appear as puckered leaves and stunted growth.
And while all or partly red tomatoes can tolerate these same low temperatures, they really do best at temperatures above 50º F. After a few days at or below 40º F, flavor, firmness, and shelf life start to diminish.
Protecting Cucumbers from Cold
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.
A light freeze is considered 28°-32°F, and a hard freeze below 28°F. However, any temperature below 25°F is dangerous territory for most vegetable plants.