When the temperature gets extremely cold, tender plants require protection from the elements. It may not be not feasible to bring in-ground plants or ones in very large containers indoors, but you can cover them to protect them from frigid temperatures. You can buy supplies specifically for this purpose or use standard household items. Follow these tips for covering plants in cold weather to provide them with maximum protection.
Know Your Plants' Cold Tolerance
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. You'll need to look up each of your plants to verify its cold tolerance. I find this list of commonly grown plants and their cold tolerance to be helpful.
Put Hoops Over Your Planting Beds
It's a good idea to put hoops over your planting beds so that it's easy to hold covers in place when you need to protect your outdoor plants from the elements. You can do this with raised or in-ground beds at whatever height makes sense based on what you plant in them. I have these on several raised beds - I use them with frost cover in the winter and shade cloth in the summer.
Purchase Commercial Plant Covers
If you do a good bit of cold-weather gardening or live where temperatures stay below freezing both night and day, it's a good idea to invest in frost cloth or row covers that you can use to protect your plants during winter. Commercial plant covers allow light and air through, so you can leave them on your plants for extended periods. They don't have to be removed during the day. I use these on my frost-resistant vegetables.
Cover Plants With Burlap
Burlap is also a good material to use for covering plants. You can purchase rolls of burlap plant covering to drape over plants or burlap plant cover bags to drop over them and secure at the ground. The bags work very well for small trees and shrubs. Buying burlap is a bit of an investment, but you can use it over and over. You'll be able to use it for years as long as you dry it off and store it after use.
Save Old Bedding to Cover Plants
When you have old bedsheets or comforters, don't toss them. Instead, repurpose them to cover plants in cold weather. If you don't have any, buy some at your favorite thrift store. I keep a stack of worn out bedding on hand to use for this purpose. I store the items in a dresser drawer, then pull them out to cover my plants when frigid weather strikes. It's important to remove this type of cover during the day when the temperature climbs above freezing.
Repurpose Tarps as Plant Covers
Tarps also work great as row covers. They're particularly helpful when it's snowing or sleeting. Frozen precipitation might leak through sheets and comforters, but tarps can help repel it. Adding tarps over fabric covers provides extra protection. As with household fabrics, it's best to remove tarps during daylight hours so that the plants can get the light and air they need. I use tarps placed over sheets and comforters when it snows.
Use Plastic Sheeting Over Other Material
You can use plastic sheeting to protect your plants against cold weather, but the best way to use it is to put it over another type of cover. For example, if you're expecting snow and ice and you usually cover your plants with old sheets, add plastic over the sheets. The sheets will keep the plastic off the plants (which could cause damage in frigid temps), and the plastic will keep precipitation from getting through.
Cover Small Plants With Plastic Buckets
Do you have a stockpile of plastic buckets? Utility buckets - or even trash cans - can be very useful for covering small plants in cold weather. You can use them on their own, or - for extreme conditions - swaddle a plant in fabric and add a bucket over the top. I often do this when it snows. As with other covers fashioned from household items, buckets will block air and light from plants and so shouldn't stay on during the day.
Place Cardboard Boxes Over Plants
You can also use cardboard boxes to cover your plants. They won't keep precipitation off plants as throughly as plastic buckets will, but cardboard boxes can absolutely help protect plants against freezing temperatures and cold wind. So, during the winter, don't break down all your boxes for recycling immediately. Keep some of intact in case you need them to protect plants. If it's super cold, wrap the plants in fabric and put a box over the top.
Secure Plant Covers in Place
Whatever you cover your plants with in cold weather, make sure the material or container completely covers the plant. It should be flush with the ground and held securely in place so that it doesn't blow up or away. I use greenhouse clamps when covering tall raised beds. When using boxes, sheets, or fabric that drapes to the ground, I put bricks on the bottom to hold them in place. Use tent stakes to help hold buckets in place.
More Ways to Protect Plants From the Cold
Covering your plants in extremely cold temperatures is very important, but it's not the only thing you can do to help keep them safe. Follow these tips to boost their cold weather wellbeing:
- Realize that the weather forecast may not be precise. If the forecast calls for the temperature to drop to within a few degrees of your plants' cold tolerance, it's best to cover them.
- Bring plants that are in small containers into your house or garage to protect them from the cold.
- Move large potted plants into your house or another structure so they'll be at least somewhat sheltered by a wall.
- Mulch your plants with straw, hay, wood chips, leaves, etc. before first frost, then add more throughout the winter. In winter, a three to five-inch layer of mulch provides helpful insulation to protect your plants.
- Water your plants a few days before you expect freezing temperatures to make sure they're well hydrated. Being well watered before a freeze can help improve their survival chances.
- Water your plants in the daytime just before a freeze sets in, even if you just watered them a few days ago. This will create warmth in the soil, which will last for a little while after the freeze sets in.
Take Care to Protect Your Plants in Winter
The time to decide how to protect your plants in the winter before it freezes. Consider the methods above and decide what supplies you need to get. Order them well before first frost and keep them handy. Watch the weather forecast closely throughout winter, so you'll know when your plants need an extra layer of protection.