Tomatoes, peppers, eggplants, cucumbers, squash, pumpkins, any melon, basil, and green beans need to be protected in the vegetable garden. Most annual flowers are fairly susceptible to frost damage. So if you bought a flower in a small plastic three or four pack, that plant probably needs to be covered.
Frost Tender Vegetables: Killed or damaged by a light freeze
Beans, Corn, Cucumber, Melons, Okra, Pumpkins (may continue to ripen after a frost, but storage life will be decreased), Roselle, Sesame, Squash, and Sweet Potatoes (harvest before soil temperature goes below 50°F [10°C]).
Silts or silty clay soils are considered amongst the most frost susceptible. Silt, because of the extremely small size of its particles, or gradation, permits and encourages the flow of water by capillary action through its pores.
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.
A light frost may cause minimal damage while a severe frost may kill plants. Young, vulnerable plants are much more susceptible to a light freeze, which occurs when temperatures are 29 to 32 degrees Fahrenheit, while mature plants may only suffer from short-term effects.
Despite its convenience, there's one item you should stay away from to cover your plants. 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.
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.
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.
This is a very important question to ask yourself. A rule of thumb: If the dew point is above 45 degrees at sunset then you are probably OK. Below 40 degrees you will probably see a frost if the other conditions are good.
Fabric coverings will prevent the freezing air from coming into direct contact with the moisture on the plant while also capturing the heat that is radiating from the ground. Bed sheets or comforters work best for covering large plants and shrubs.
Thoroughly Water plants if it won't rain before the freezing temperatures arrive. It may sound illogical. However, the moist ground stays warmer than dry soil. Watering the night before the freeze will insulate the grass and plants' root structure and decrease the potential for cold injury.
Vegetables, annuals, and tropical plants planted outdoors early in the season are the most important plants to protect during a late frost or freeze event in spring. Protecting emerging spring bulbs and perennials is not necessary.
Field peas are the most frost susceptible pulse crop followed by faba beans and lupins.
Hosta can withstand a freeze; they are hardy perennial plants that live in hardiness zones 3-9. However, Hostas can still suffer from frost damage and freeze in certain circumstances.
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.
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.
Below 63°F, cucumbers do not grow. In such conditions, plants sit in the soil and become susceptible to damages caused by pests in the soil. With that said, check soil temperatures and be sure they are above 63°F before planting cucumbers.
Plastic can be used to protect plants from frost, but it's not the best or most effective material. In fact, the horticultural experts here at Green Impressions actually recommend against it.
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.
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.
From that experience, I've found the best frost protection for your outdoor plants is either free or cheap. Cardboard boxes and brown grocery sacks make perfect frost cover and at the end of the season can be recycled. I keep various boxes on the patio and when frost is forecast simply put one over the plant.
Zip bag closed. Place your closed baggy in a window that receives a good amount of sun (Bean side up). You can also tape your baggy to the window (Bean side out). For the next few days, check in on your plant in the window to see how seeds produce growth!