As the cold weather approaches, many gardeners consider covering their vegetable beds and flower gardens with plastic sheeting to protect plants from frost and cold temperatures. But is this really the best winterization method? Here we’ll examine the pros and cons of using plastic covers on garden beds over winter to help you decide if it’s right for your landscape.
An Overview of Covering Gardens with Plastic in Winter
Covering garden beds with plastic sheets or tarps for the winter is a practice that many gardeners swear by The idea is that the plastic acts as an insulating layer to protect plants from frigid air temperatures and retain heat absorbed by the soil during the day, This can help buffer delicate plants against frost and freezing, The plastic also blocks light which prevents weeds from sprouting And it can conserve soil moisture,
Some gardeners use plastic to cover their perennial flower beds, roses, strawberries, and other ornamentals that can die in the winter while they are dormant. People who garden vegetables may cover up beds that aren’t being used to plant early spring crops like peas. When the plastic is taken off in early spring, the warmed soil gives the seedlings a head start.
So in theory, plastic covering allows you to grow plants that might not otherwise survive your winter, and get a jump on spring planting. But it also has some potential drawbacks. Let’s analyze the pros and cons so you can decide if it’s right for your landscape.
Potential Benefits of Covering Gardens with Plastic
Here are a few of the main reasons why gardeners put plastic over their beds in the winter:
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Warms the soil – The black plastic absorbs heat from sunlight during the day and releases it slowly at night. This can warm the soil underneath by several degrees compared to unprotected ground.
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Earlier spring growth – The warmer soil temperatures under the plastic in early spring hasten plant growth. This allows earlier planting and harvests.
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Controls weeds – The solid plastic sheet blocks sunlight entirely preventing weed seeds under it from sprouting. This can significantly reduce weeding labor when you uncover beds.
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Conserves moisture – The plastic minimizes surface evaporation which keeps soil underneath moist. This helps plants remain hydrated in winter and saves watering labor later.
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Protects from frost—The plastic may keep plants from getting too cold by insulating them a degree or two. It’s not reliable for hard freezes, but it might be useful in the shoulder seasons.
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Takes up leftover plastic – Making use of old plastic tarps or drop cloths that might otherwise end up in a landfill gives them a second life.
Potential Problems With Covering Gardens in Plastic
But there are some problems with putting plastic over garden beds in the winter that you should think about:
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Promotes disease and fungi – Wet soil trapped under solid plastic can foster mildew, mold, blights, and root rot issues. These may linger into spring and infect young seedlings.
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Harms helpful soil organisms – The anaerobic environment under plastic kills off beneficial earthworms, bacteria, and other critters that maintain healthy soil ecology.
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Kills living mulches – Any cover crops like clover or rye you have growing will suffocate and die when covered for an extended period.
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Traps pests – Snails, slugs, and other pests may take shelter under the plastic and breed rapidly in the warm, moist conditions it creates.
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Looks messy – A big blue plastic tarp covering a garden bed is an eyesore to many gardeners, and neighbors may complain.
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Blows away in wind – The plastic sheeting catches gusts of wind like a sail and can fly off the bed if not weighed down properly on all sides.
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Creates plastic trash – Even thicker plastic sheets degrade over a season. This leaves you with smaller fragments to responsibly dispose of later.
Best Practices for Covering Beds
If you decide the benefits outweigh the risks in your climate, here are some tips for safely using plastic:
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Use only UV-stabilized, heavy duty 6-10 mil construction grade plastic. Lightweight thin plastic will quickly shred and fly away.
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Secure all 4 edges with heavy bricks, rocks, or garden staples. Bury edges if possible. Check often for wind lifting edges.
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Apply plastic as late in fall as possible once cooler weather settles in so you don’t trap active pests underneath while still warm.
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Remove the plastic as soon as your soil thaws in early spring. Especially uncover immediately once plants start growing underneath.
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Reuse intact plastic sheets over subsequent winters. Properly dispose of any fragments that have become brittle or ripped.
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Replenish soil nutrients by top dressing beds with finished compost after removing plastic.
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Scout for pests and treat any fungal outbreaks quickly before they spread to young plants.
Alternatives to Plastic Coverings for Winter Protection
If you want to avoid the risks of solid plastic coverings, effective organic alternatives exist:
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Apply 6-8 inches of shredded leaves, straw, or evergreen boughs as loose mulch cover. Still provides insulation against frost while allowing airflow.
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Grow cold-hardy cover crops like winter rye and hairy vetch. They continue generating organic matter through winter while suppressing weeds.
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Cover beds with breathable row cover fabric hooped over wires. Allows ventilation while still trapping warmth. Can incorporate low tunnels.
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Heavily amend soil with finished compost in fall to feed soil biology and boost organic matter before winter.
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Use corn gluten-based organic pre-emergent herbicides in spring rather than relying on plastic sheeting for weed prevention.
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Employ organic physical controls like copper tape, diatomaceous earth, and insect barrier fabrics to prevent pest damage without plastic.
Covering vegetable gardens and ornamental beds with plastic sheeting or tarps for winter does offer some benefits, especially in regions with harsh winters. But it also carries risks like encouraging soil diseases, pests, and killing off helpful soil life. Safer organic alternatives like mulching and cold-tolerant cover crops typically provide adequate insulation and protection for most gardens. Carefully weigh your specific climate and gardening goals when deciding if plastic covering is the right solution for winterizing your beds. With prudent preparations, most gardens can successfully weather winter without plastic.
Sheet Mulching to Start a New Garden
When I started my very first garden, I double-dug it. It was extremely hard work, and when I look back, I shake my head at myself. I’d not heard of no-dig gardening back then and was only following advice I’d learned from more experienced gardeners. I now practice no-dig, which means I don’t turn over the soil when I start a new bed or turn the soil at any other time of the year. Instead, I spread compost over the soil and call it a day. My over 200,000 YouTube subscribers can vouch for me that it works!
Using black plastic to kill weeds is often the first step in creating a new no-dig garden. However, it’s an excellent method for clearing land, no matter what type of garden you plan on building. A traditionally dug garden, raised beds, or a no-dig garden. What it involves is cutting the grass and weeds down as best you can. Then you cover the area with thick, dark plastic sheeting, weigh it down, and allow it to suppress growth and eventually kill everything that was growing underneath it. Even perennial weeds. This technique, a temporary form of sheet mulching, works through light exclusion and soil polarization. The thickness of the plastic makes it dark, and plastic traps heat and creates a kind of greenhouse effect underneath.
The Type of Black Plastic to Use
It’s really easy to clear land using black plastic, and I’m going to lay it out for you below. Before you begin, you will need heavy-duty black plastic sheeting large enough to cover the area completely. It can be all one piece or layered in a way so that plants cannot grow through. This polythene plastic is thicker than garbage bags and is sometimes called Visqueen. It’s so thick that light cannot pass through it and won’t rip very easily, either. Typically, the black plastic you use to clear land should be at least a 1000 g gauge, so it’s pretty thick.
Though I say black plastic, I’m referring to the usual color of Visqueen. I’ve seen it in other colors, including light blue, which will work as long as light cannot get through it. That’s because plants need light for photosynthesis; if it’s excluded, they die. That’s what you’re aiming for! If you use plastic sheeting that allows light through, then the plants underneath will not die. That’s the case with using standard blue plastic tarps or clear plastic. If the plastic is too thin, some plants can grow through it, and the weather can tear and break down the plastic.
A little inspiration idea to upgrade your garden bed
FAQ
Should I cover my garden with plastic in the winter?
Covering with a plastic sheet or cardboard can also help to reduce soil erosion in your growing beds as well as holding in more nutrients. A lot of people also cover beds in the late winter as a way of warming up the soil quicker so they can start their planting a little earlier.
Should I cover my garden with black plastic?
Black plastic mulch preserves soil moisture by preventing evaporation of soil moisture.Dec 22, 2022
What to cover a garden with in winter?
For winter garden protection, consider using materials like mulch, straw, frost blankets, or even cover crops. Mulch, such as leaves or wood chips, insulates the soil, retains moisture, and suppresses weeds. Straw is another good option for insulation and overwintering insects and animals, according to OSC Seeds. Frost blankets, available at garden centers, offer lightweight insulation and allow for airflow.
Can I cover plants with plastic for frost?
What Do You Need to Protect Plants from Frost? 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. Oct 18, 2021.