Yes – if you secure the plant properly. Garbage bags work to cover plants and protect from frost, but they must not be allowed to touch the plant's surface. Use stakes and supports to create a tent-like structure over the plant, which will retain warm air. Make sure the trash bag goes all the way to the ground.
Can You Use Garbage Bags to Cover Your Plants? Usually, covering plants with any plastic material isn't safe. However, you can cover your plants with garbage bags to protect them from pests and pest-carried diseases and sometimes excess moisture from too much rainfall.
Covering Plants with Plastic Bags
Plants under plastic bags retain moisture and even capture what the plants produce by transpiration. Don't use plastic bags as a greenhouse for succulents, though, as they can definitely tolerate neglect, but won't tolerate this kind of moisture.
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. Plastic materials such as vinyl and traditional camping tarps aren't breathable, causing moisture to get trapped inside.
Plastic – Plastic is definitely not the best winter covering for plants, as plastic, which doesn't breathe, can trap moisture that can kill the plant in a freeze. You can use plastic in a pinch, however (even a plastic garbage bag), but remove the covering first thing in the morning.
Bed sheets or comforters work best for covering large plants and shrubs. Newspaper can be used on low-growing foliage, but it can often be difficult to get it to stay in place. You can also use old pillowcases, sheets, towels and even cardboard boxes.
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.
-Don't make the mistake of thinking that a plant can remain covered for a few days when the weather calls for more than one night of frost. The protection needs to be taken off every morning when the sun comes out. Plants can't breathe under a heavy container, a layer of plastic or fabric.
Use stakes or another support to keep the covering from directly touching the plants. Covering plants helps protect them from a freeze because it helps retain heat radiating from the soil and keeps them warm overnight.
Yes, that's right: plants provide all the “air” they need for their own survival. They're perfectly happy sealed in a plastic bag. How long can you keep your plants sealed up like this? Easily 6 months, quite possibly up to a year.
Plastic will transmit cold air to the plants, causing more harm than good. We recommend using cotton fabric or frost cloth to protect plants from frost.
To know when to cover your plants, you need to know when the plants you have are susceptible to frost damage. Some frost-tender plants need to be covered as soon as the temperature hits 32°F, while others can handle lower temperatures and/or longer freezing periods.
In order to provide light, greenhouses need to have some way for the light to come in. This is why greenhouses are made of mostly translucent materials, like glass or clear plastic. This gives the plants inside maximum access to sunlight.
Container plants are particularly vulnerable to the cold because their roots aren't in the ground. If possible, move plants inside a garage, shed or basement. If you're leaving them outside, push them together and cover them. Wrap the containers in plastic or burlap to help them stay warmer.
When Should You Cover Plants? Cover your plants at night and remove them during the day when the temperatures rise above 32 degrees F, so that the soil can warm up again. Some outdoor plants won't survive the harsh conditions of winter, bring them inside and use these tips for caring for them through winter.
Why use bed sheets to protect plants from frost? 'Using bed sheets in the garden to prevent plants from frost is a great way to protect your plants from the cold temperatures and keep them healthy,' explains Zeeshan Haider, the CEO of Greenery Enthusiast.
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.
(If freezing temperatures are predicted for several consecutive nights, it's safe to leave your plants covered for up to a week. Some of your neighbors, however, may not be happy about this.) Small old fashion electric Christmas lights hung or placed near the base of the plant (heat rises) will add warmth to a plant.
I like to take buckets and put them upside down over a plant. This works great for individual plants, like tomatoes and peppers. Push the top of the bucket down into the soil. That will make a nice seal, and keep more cold air out.
A hard frost happens when temperatures hover around 32˚F for a few hours, enough to kill all above-ground parts. Below 32˚F is considered a freeze, which is more destructive than a frost. Tender plants, such as tropical houseplants and geraniums, are killed when the air temperature stays below 32˚F for a few hours.
Use a frost blanket, cloche or row cover material – not plastic — to insulate the ground around your outdoor plants and keep them warm. Prop the cover with sticks or stakes to keep it from coming into direct contact with the new growth. And, make sure to remove the cover the next morning after the temperature warms up.
Burlap is more effective than plastic because it allows the plant to breathe so air circulates and heat isn't trapped. Burlap for protecting plants can be as simple as an old burlap bag. If you don't have access to burlap bags, you can purchase sheet burlap by the yard at most fabric stores.
Verdict: Some type 7 plastics contain BPA, a harmful compound that has been linked to many adverse health effects. Stay away from type 7 plastics in your garden.