Daytime temperatures below 65°F can lead to fruit set failure—the pepper equivalent of stage fright. At night, anything under 50°F is an invitation to leaf curl and overall plant stress. It's like the plants are pulling their leaves up to their chins, trying to keep warm.
So will peppers survive 40 degrees? To sum it up, most peppers won't necessarily DIE from 40˚ F temperatures, but their growth can be stunted, and they may be slow to recover so it's best to keep them warm if possible.
Dry soil, temperatures above 90°F, or night temperatures below 60°F or above 70°F, can weaken plant growth. Transplant in late afternoon or on a cloudy, calm day. Pepper flavor is best when the season has been warm and sunny.
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.
Before the Risk of Frostbite: If you're growing pepper varieties that are especially sensitive to cold, consider bringing them indoors even earlier, when nighttime temperatures are consistently above 55°F. This will help prevent any potential damage to the plants.
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. * Cover plants at night.
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.
Scientists in the ARS Photosynthesis Research Unit at Urbana, Illinois, have discovered a drop in the overnight temperature below 50°F can create a biochemical version of mission impossible for some crops like tomatoes, soybeans, and corn.
Mature pepper plants will be completely fine with nighttime temperatures down to 40F. Below 40, they will really slow down their growth. A light frost will damage a lot of the outer growth. A hard frost will completely kill them.
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.
For pepper plants, a balanced fertilizer with equal proportions of Nitrogen (N), Phosphorus (P), and Potassium (K) is recommended. However, pepper plants respond positively to higher nitrogen concentrations during the flowering stage.
Peppers really like temperatures above 55-60˚ F if possible, so covering them on cold nights or during cold weather is best. The same goes for tomatoes, basil, and other warm-season vegetables! Keep them warm if possible.
❄️ Signs of Cold Stress
Conversely, shivering peppers aren't happy peppers. Daytime temperatures below 65°F can lead to fruit set failure—the pepper equivalent of stage fright. At night, anything under 50°F is an invitation to leaf curl and overall plant stress.
Hold back on planting for two weeks after the risk of frost. After planting, protect your plants (pepper plants in particular) from the wind and cold by wrapping a sheet of clear plastic around several plants in such a way as to create a fence, or wrap a single tomato cage (one plant) at a time in clear plastic.
Temperatures below 60°F at night will also result in blossom drop. At temperatures below 40°F, peppers may show some chilling injury.
Set Your Pepper Plant in a Cool, Sheltered Spot to Overwinter. Move your potted plant to a spot that gets a little bit of sunlight (next to a windowsill is great). If you're doing a garage or shed, make sure the temperature won't drop below the 50s. After a couple of weeks, your plants might begin regrowing leaves.
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)
So, yes, it's been cold at night around Southern California, but folks, 45 degrees is a still a long way from the freezing temps that can burn our tender tropicals and other plants, like a multiday cold snap in 2007 that severely damaged crops in Central and Southern California.
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.
Option 1: Insulated Plant Protector
An insulated plant protector (sometimes known as a Season Starter™) is a ring of vertical plastic tubes filled with water to form a warming enclosure around an individual tomato plant (or another warm-season veggie like a pepper).
In the case of peppers, the ideal daytime temperature is 21-26°C (70-80°F). The ideal nighttime temperature is 18-21°C (65-70°F). Of course, these ranges may vary, depending on the pepper varieties you grow. Pepper plants may still grow outside of the ideal temperature range.
If you're looking for tips for protecting your plants from frost, avoid using garbage bags as plant covers. Trash bags are not the best protection against frost damage, primarily due to their material. Most garbage bags are made out of low-density polyethylene plastic.
Summer squash can also be damaged by frost and temperatures below 50°F (10°C). Zucchini, like other summer squash, prefer warm temperatures between 70-95°F (21-35°C).