As the cold weather sets in, garden activity winds down and gardeners seek refuge indoors. While indoors, their plants can receive an unexpected visit from midwinter’s frost. Even if the threat of winter has not yet approached, sudden plunges in temperature can devastate entire sections of your garden crops. To alleviate the adverse effects of frost, it is important to seek some sort of protection for your garden crops. It is easy for beginners to get confused and neglect this aspect, but advanced gardeners caution against this – just a single night of frost can kill your crops overnight. Below are several tips to help winterize your garden against the harsh winter and ensure your garden’s survival for next year.
When to Start
To know when to start preparing, gain a basic understanding of the weather patterns and frost dates of your area. When temperatures fall below 32°F, take out your frost covers. Most plants will freeze when temperatures remain at 28°F for five hours. Signs of frost damage, which initially targets new foliage and growth, include wilted growth and blackened leaves. Desiccation, a term that refers to the drying out of a plant, is a common symptom during winter months. Afflicted plants, particularly evergreens, exhibit browned and discolored foliage before they wither and die. Once a plant has sustained frost damage, it is unable to be reversed. However, there are precautions you can take and depending on the extent of the damage, the plant may recover.
The general classifications of freezing are listed based on their effects:
- Light freeze: 29° to 32°F – tender plants are killed
- Moderate freeze: 25° to 28°F – destructive to most vegetation
- Severe freeze: 24°F and colder – heavy damage to most garden plants
Which Plants to Protect
Certain categories of plants will need protection, including young seedlings and new growth, tender perennials, half-hardy varieties, and tropical and subtropical species. Plants are commonly classified as hardy, half-hardy, or tender. To ascertain the hardiness of specific plants, consult your seed packet or conduct a quick search online. Hardy plants can be thought of as traditional foodstuffs grown by early settlers. They generally contain high levels of sugar and can survive in a vegetative state until next spring. Leaving them in the ground can actually improve their flavor. Semi-hardy plants can withstand brief periods of light frost, but beyond that, would require protection. Tender plants are easily damaged by cold weather and need to be brought inside. Below is a list of common vegetables grown by gardeners and their hardiness classifications.
Hardy Vegetables (Frost Hardy; below 28°F)
Frost-Tolerant Vegetables (Can withstand light frost; 28 – 32°F)
- Garlic, onion, chives
Tender Vegetables (no frost)
- Pumpkin, squash
- Bring Plants Indoors
The easiest way is to bring potted plants indoors. The ideal location is an area that receives plenty of bright but indirect light. Gradually acclimate them to the indoors by placing them in a shaded spot before moving them inside. Some may lose their leaves and go dormant, while others slow down their growth and become semi-dormant. At this stage, cut back on the watering and fertilizing – depending on the temperature and container size, they may only require watering 3 – 4 weeks. Overwatering can cause root rot to occur.
Some gardeners also choose to overwinter potted plants in a conservatory, garage, or frost-free greenhouse. Vego Garden features a collection of sturdy, functional rolling beds that you can easily wheel inside during frosty months. Whether you’re seeking to grow fruit trees on the patio or whimsical blooms on the balcony, these rolling planters offer an inventive way to transport delicate plants safely inside.
- Use Frost Covers
For large plantings, frost covers are recommended. Makeshift frost covers include drop cloths, sheets, blankets, or even newspapers. Plastic can be used, but it is not a salient option. It can create an impermeable layer that suffocates plants and cause moisture to become trapped inside, exacerbating the situation. Fabric coverings made from natural materials like cotton, linen, or burlap are recommended because they allow moisture to escape while protecting your plants. One method is to cover larger plants and shrubs with horticultural fleece. You can also choose to purchase pre-designed coverings for a more visually appealing look and greater ease of mind. In the morning, remove coverings or sheets after the frost dissipates and temperatures rise.
- Add a Layer of Mulch
While many gardeners neglect mulching during the winter, a layer of mulch can shield dormant roots from harsh freezes, thaws, and winds. Unlike during the growing season, when mulch is used to suppress weeds and retain moisture, mulching in cold climate gardens is used to protect plants from alternatively freezing and thawing temperatures, which can damage the bulb and roots. The timing is important, as applying too early or too late could adversely affect the plant. The ideal time is after the first hard frost. Add an even layer of two to three inches of mulch to stabilize the soil temperature. Natural mulch sources are preferred, such as pine and evergreen trimmings, grass clippings, and straw.
- Harvest Plants Early
Sometimes, an early harvest is necessary during periods of volatile weather. Tomatoes and peppers will continue to ripen indoors if picked green. Tender herbs and vegetables such as beans, peas, and corn should be picked early to avoid the threat of frost. After harvest, it can be daunting to deal with the surplus of vegetables and fruits. To extend the shelf life of your harvest, try preserving herbs, and canning, drying, and freezing fruits and vegetables.
- Use a Cloche or Glass Bell
If you do not have a large planting area, consider using a cloche. Tender plants and small seedlings can be protected with a cloche or glass bell. A cloche is a bell-shaped clear or plastic cover that can be used to protect plants from frost or pests. Used to cover individual plants, they add a quaint country look to the garden. You can purchase your own or create a makeshift one out of recycled objects. Remove the cloche during the day after the danger of frost has passed to allow ventilation and sunlight to filter through.
- Choose Plants Suitable to the Climate
For those that don’t have the time or simply want to stay indoors, choose established plant species that are suited to your growing zone. Many root vegetables like carrots, onions, potatoes, and garlic can tolerate a light frost. Other cool-weather vegetables include kale, cabbage, leeks, and radishes – in some cases, the cold will improve the flavor of the crop. Evergreen trees and shrubs are hardy and can easily survive frost. Winter plants and flowers, some of which are surprisingly colorful, can also be planted for visual interest.
- Water in the Morning
Although it may not seem necessary to water plants during the winter, supplemental watering is recommended for newly planted shrubs, woody plants with shallow roots, and certain herbaceous perennials. Roots are prone to drying in the winter, which is exacerbated in areas with drying winds. Watering early in the day is beneficial because the water in the soil will trap heat and create an insulating effect.