QUESTION: Fabric or plastic is the best material to use as a cover to shield outside plants from the chilly air.
When the temperature drops low enough to cause the moisture on plant leaves and buds to freeze, the threat of frost typically materializes overnight. You must cover plants to prevent the moisture from freezing in order to protect them from cold. It’s crucial to utilize the proper materials, even though an unexpected cold can leave many gardeners racing to find something to cover their sensitive plants.
It is ideal to use a cotton covering because it will let moisture out while yet shielding your plants from cold. Fabric coverings will both capture the heat that is radiating from the ground and stop the freezing air from coming into direct contact with the wetness on the plant. Large plants and shrubs are best covered with bed linens or comforters. Newspaper can be used to low-growing vegetation, but it can frequently be challenging to make it stay put. I have recycled old towels, sheets, and even cardboard boxes as well as pillowcases. Whatever you choose to use to cover your plant, just make sure the canopy traps the warm air within and extends to the ground.
You can use plastic, but it’s crucial to remember that you shouldn’t let it touch your plants. Because it can hold moisture against plant tissues and worsen freezing damage, plastic that comes into contact with your plants is frequently much worse than no protection. For their frost-sensitive plants, many gardeners will frequently install high stakes or forms so they can cover them and secure them without worrying about the coverings blowing away at night or harming the branches. As long as the plastic won’t come in contact with the plant in any manner, it is acceptable to cover a structure like this with plastic.
And keep in mind that the more cover layers there are, the better the insulation is. So, feel free to cover priceless or delicate plants with more than one cover, especially during really cold temperatures. You may, for instance, cover the plant with a sheet of plastic and then an old blanket.
Whatever method you choose, it’s crucial to remove the covering as soon as the risk of frost has gone so that the plant can absorb light and to avoid heat buildup when the sun comes out.
When should outdoor plants be covered?
We are lucky to be able to cultivate semi-tropical and/or tropical plants, such Bougainvillea, Lantana, and Yellow Bells, outdoors if we reside in regions with moderate winters.
The frost-sensitive plants, whose vibrant blossoms we love in the summer, frequently require additional care in the winter. When is the final frost? Even gardeners in chilly climates have to make a guess.
Damage to the leaves and occasionally even to the roots can happen when temperatures fall between 32 and 24 degrees F.
How to Protect Plants From Frost
What can you do, then, to help safeguard your frost-sensitive plants? During the chilly nighttime hours, cover them. The soil absorbs the heat of the sun during the day. When plants are covered in the evening, the heat that the earth radiates back into the night is trapped by the covering.
What Should You Cover Plants With?
You might be unsure about the best coverings to use on your frost-sensitive plants.
You might do as we do and go through your linen cupboard for used blankets, sheets, and towels. Of course, you can also use frost cloth and burlap from your neighborhood nursery. Frost protection fabric is available on Amazon.
How are outside potted plants covered?
You might need to give your pots additional protection depending on where you reside. The following are a few choices for overwintering containers:
- Put many pots next to the house or wall on the ground. Put the cold-hardiest plants outside the grouping, and the weaker ones in the middle. Place straw bales around the outside. Putting them together improves the insulation’s mass and volume, shielding them from chilly breezes that could cause freezing and desiccation.
- Mulch pots with straw, mulch, or chopped leaves for further insulation. Snow is a wonderful insulator as well. Grouping pots in a premade pond liner and filling it with mulch is an intriguing concept for insulating containers.
- The only insulation for roots is the wall of the pot itself because the majority of roots usually tend to be on the exterior of the rootball. To insulate roots, place foam along the walls of square pots that is at least an inch thick before planting. Fill the internal walls of rounded pots with foam peanuts.
- Fill the container up with soil and bury the pots there.
- Plant the rootball in the ground after removing it from the container. Clean the container, then keep it inside. Next year, remove the root ball and repot it in the same or a bigger container.
- Burlap, bubble wrap, old blankets, or geotextile blankets can all be used to wrap pots. Since the roots require protection, the entire plant doesn’t need to be covered. The root zone will retain heat thanks to the support of these protective covers.
- Cover plants at night with cloth, burlap, or plastic if low temperatures are anticipated. If you use plastic, make sure to take it off during the day because the heat can hasten the growth of the buds. Additionally, when covering, take care not to harm the plants’ tops. Plant damage from the cold and pests is facilitated by injury.
- To offer further security, place your pot inside of a larger pot. The bigger pot should have extra insulation or sturdy walls for this to work optimally.
Hard freezes may be unusual to nonexistent in USDA Zones 7 through 11, therefore it may not be essential to add insulation or move pots indoors for the winter. There are several tasks, nevertheless, that you should still be mindful of. Plant development will stall in the winter because of the lower temperatures, and watering may become less regular. However, salt can accumulate in the soil and increase toxicity levels. Leach the salts out with water. As required, fertilize plants as well.
How can plants be hidden?
Frost may be fatal to our garden crops, but exercising a little caution and having a few supplies on hand will greatly improve the health of your sensitive plants.
Bring Potted Plants Inside
Because they won’t receive any insulation from the dirt like in-ground plants do, plants in pots are more vulnerable to frost damage.
Before putting plants inside your house, make sure to thoroughly check them for pests and disease. To avoid the potential spread of insects, keep plants separate from your indoor plants.
Bring all of your plants back outside as soon as the threat of frost has gone first thing in the morning.
Water Plants in the Afternoon
Keeping the soil moist can help protect plants from the cold, despite what might seem illogical.
Before a cold front, water plants in the middle of the day while it’s still quite warm outside.
Add a Thick Layer of Mulch
Use straw, wood chips, leaf mold, or even just a pile of leaves to help the plants’ underground root systems with vital insulation. Mulch thickly to a depth of 3 to 6 inches to effectively form a barrier.
To allow the warmth of the soil to rise through the plant, leave an inch or two of space around the core stalk.
Even though mulching your garden beds is one of the best low-maintenance practices you can implement, you’ll want to remove some of this protecting mulch as the weather becomes warmer.
Cover Up Individual Plants with a Cloche
You may buy plastic garden cloches like this 3-pack from Tierra Garden and reuse them as necessary during the spring and fall’s bad weather.
It would work with a bucket turned upside down or a flower pot. Alternately, remove the bottoms from plastic milk bottles and bury them in the ground.
When using cloches to protect your plants from frost, cover them just before dusk and remove them in the morning so they may take use of the sun’s warmth and energy.
Give them a Blanket
Place multiple stakes around your plants before laying down the fabric so that when you cover them, it will look like a tent.
All the way down to the soil line, let the material hang over the plants. Avoid tying it off around the plant’s stem or trunk since that will stop the earth’s heat from rising through the plant.
Add a final covering of plastic tarp or an old shower curtain, for example, for increased frost protection.
Just be careful not to let any of the plastic covering touch the leaves of your plants because plastic can harm them.
You might want to spend money on specifically made, reusable, and breathable frost blankets like this one that can be cut to size if coping with the fear of frost is a recurrent issue in your garden.
Mylar thermal blankets, also known as space blankets, help reflect 99 percent of the heat back to the soil on particularly chilly nights when the aluminized side is directed downward toward the plants.
This little hoop house kit, which includes steel hoops and a fitted, heavy-duty garden fleece covering that retains heat, is another choice for tidy and organized garden rows.
Wrap Your Trees
Younger trees, those that are between one and four years old, are far more vulnerable to frost damage, which could even result in their death.
The growth of fruit trees exposed to springtime frost will also be stunted, resulting in a smaller crop for the remainder of the growing season.
Citrus trees should be sheltered when the temperature drops to 29F since they are particularly vulnerable to frost.
Wrap the trunks of trees in rags, cardboard, towels, blankets, or pipe insulation to keep them warm.
Is it acceptable to wrap plants in plastic?
Plants may be protected in a freeze by being covered with a sheet or blanket if you are only anticipating a light frost. This serves as insulation, retaining warm air around the plant that is coming from the ground. In the event of a brief cold spell, the warmth may be sufficient to prevent a plant from freezing.
Place plastic over the sheets or blankets to assist preserve heat inside while protecting plants from a frost for further security. However, never just cover a plant with plastic because the plastic will harm the plant. To protect the plant from the plastic, place a cloth barrier in its path.
After an overnight cold snap, make sure to take off the sheets, blanket, and plastic right away. If you don’t, condensation may collect and freeze once more under the covering, harming the plant.
You might not have a choice but to expect to lose all or a portion of the plant while sheltering plants from a longer or deeper cold in the hopes that the roots will survive. Start by heavily covering the plant’s roots with hay or wood mulch. You can tuck gallon jugs of warm water into the mulch every night for additional protection. As a result, some of the cold that could harm the roots will be repelled.
In order to prevent plants from freezing, you can also surround them with insulation barriers if you have time before a frost occurs. Put the plant in a tight knot as you can. Put stakes around the plant that are the same height as it in the ground. To give the impression that the plant is fenced in, wrap the posts with burlap. Fill this fence’s interior with hay or leaves. Again, you can add to the heat each night by setting milk jugs of warm water on the inside, at the foot of this fence. Another way to increase heat is to drape a string of Christmas lights around the plant. Remove the covering as soon as the freeze is over so the plant can receive the sunlight it need.
Watering the soil rather than the plant’s leaves or stems will also assist the soil retain heat, which may aid in the survival of the plant’s roots and lower branches.
At what temperature should I frost-cover my plants?
Planting too early might result in a crisis if a cold snap is impending, whether it was because you were seduced by some striking hue at the garden center or simply wanted to start the gardening season early. It’s not difficult to help your seedlings survive the great frost, but it does take some planning.
When temperatures drop, you can usually rely on improvised protection for plants. The necessary tools must be prepared in advance to protect plants from frigid mornings for larger plantings, such as a food garden.
Knowing when prized vegetation starts to turn frost-burned brown will help you know what to do when freeze warnings are in effect. As a general rule, plants typically freeze when the temperature stays at 28°F for five hours.
There are, of course, exceptions to this rule. When temps drop to 32–33F, seedlings often die because of their delicate new leaves. There are many low-temperature thresholds for tropical plants. Some collapse at temperatures below 40°F, while others break down at 35°F. Other plants are naturally resistant and can endure temperatures as low as 18 to 20 degrees Fahrenheit. Do a search in gardening books and internet resources to discover the threshold for your plants.
Take it up
Moving plants away from potential danger is the simplest cold-protection strategy. Potted plants and seedlings in flats both benefit from this. Moving plants onto a porch with a roof, into a garage or shed, or under a deck frequently provides sufficient shelter.
Rely on Water
Just before sunset, water the soil to raise the temperature of the surrounding air overnight as the water evaporates. Water-filled buckets or gallon jugs should be left in the sun all day. Move them close to threatened plants at night. Air temperatures will be moderated by the water, and if it freezes, heat will be released. To boost midday heating, paint a few water-holding containers black for best results.
the air flowing
The biggest harm is done to plants by cold, motionless air. To prevent frost from accumulating on plants, you can use an electric fan all night to create a breeze. Never forget to keep electrical connections dry.
Plants Should Be CoveredPlants should be covered with sheets, towels, blankets, cardboard, or a tarp to protect them from everything but the harshest freezing (28F for five hours). Inverting baskets, coolers, or any other container with a firm bottom over plants is also an option. Before it gets dark, cover plants to keep warm air in. Coverings shouldn’t ideally contact the foliage. If windy conditions are anticipated, anchor cloth coverings.
When the temperature rises and the frost has melted in the morning, remove coverings. Under dense covers, heat from the sun can accumulate and cause plant death.
Blankets that collapse
Row covers, or gardening blankets, should always be accessible. These covers are created in various thicknesses from plastic or synthetic fibers. Lay row covers directly on the plants, or suspend them over a bed with pegs to form a tunnel.
Activate lights
An incandescent light bulb produces enough heat to raise the temperature of the air around it just enough to keep a plant from freezing. For this method to operate, bulbs must be close to plants (within a distance of 2-3 feet). (Fluorescent bulbs can’t produce enough heat to complete this task.)
Defend specific plants
Set up hot caps
At planting time, stiff plastic containers with venting holes are placed over the individual seedlings. Hot caps function similarly to cloches (small greenhouses), but the daily task of applying and removing the covering is eliminated by venting holes. Use plastic two-liter bottles or gallon jugs with the bottoms cut off and the lids removed to simulate a hot cap (but saved). In the evenings when the weather turns chilly, replace the lids.
A Wall O’Water tepee, which encircles individual plants with a sleeve of water-filled tubes, is a variation on the hot cap concept. During the day, the water absorbs the heat of the sun. The water gently freezes at night, releasing the sun’s stored radiant heat and preventing the air within the tepee from becoming frosty.