How to Protect Your Garden From Early Frosts
First frosts are never welcome! If you’re like me, you’re trying to hang onto summer weather before freezing winter arrives. Frost threatens tender crops and wildflowers while they grow. With some protection, your garden can continue performing through autumn. See how to protect your plants when they need it most with Pacific Northwest gardener Jerad Bryant.
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Early frosts are no fun, especially if you still have some crops growing that aren’t ready to harvest. They’ll reduce tomatoes, peppers, and eggplants to piles of mushy, wet stems overnight. Frost is a common factor when gardening—learning to manage it gives you more time to start seeds, harvest vegetables, and prepare perennials for hard freezes.
Some plant species handle light frosts and continue performing well, like pansies, hellebores, and kale. Decorate the yard with these species for fall colors no matter how cold it gets. More plants living in the ground traps warmth below the soil, as their roots hold onto water and air. The more frost-tolerant plants you grow, the better!
There are other considerations for early garden frost preparedness aside from taking care of your plants, like protecting irrigation systems and mulching the soil. With a little maintenance and some care, your garden will stay in tip-top shape no matter how cold it gets.
Critter Cover Frost Blanket (10 pack)
Protect your young seedlings from frost, sunlight, and pests, or extend your season using our Critter Cover Frost Blankets. Safeguard plants from frost and cold – down to 22°F (-5°C).
Stop Fertilizing
Excess fertilizer in fall tricks plants into growing more stems, leaves, and sometimes flowers. The flood of nutrients convinces them it’s time to grow despite the approaching winter weather. Some species, like woody ones, need to harden off their stems and buds, and fertilizer prevents this process.
The best time to stop fertilizing is late summer before the leaves start changing colors. You can still add compost or mulch, as it’s much slower working than instant fertilizers. For cold-hardy species, this will help them winterize properly with frost-proof twigs, buds, and branches.
Crops like tomatoes or peppers rush to produce fruits before freezing temperatures kill them. They grow flowers with reckless abandon! You may fertilize them if they need it while they ripen their vegetables or fruits. Cease fertilizing if they grow near perennial species that are preparing for winter. Your safest bet is to apply compost or mulch for a slower-working nutrient addition.
Harvest Partially Ripe Fruit
You’ll want to ripen your crops indoors unless you’re growing pumpkins, apples, or a similar species with frost-tolerant fruits. Tomatoes, peppers, eggplants, broccoli heads, and many other crops turn mushy after the first frost. The water inside them freezes and thaws, causing ruptures that invite pests and diseases.
Some fruits, like tomatoes, ripen easily indoors. Simply place them in a single layer in a cardboard box and store them in a cool, dark location like a pantry, garage, or indoor porch. They’ll ripen slowly; check on them weekly to ensure none rot or overripen.
Other fruits, like apples, ripen well in your refrigerator. Most apple farmers store apples this way to keep birds and small mammals from attacking their crops. Simply harvest them in the fall, then place them in your crisper drawer in the fridge. They’ll ripen with time, and you can devour them when they’re ready.
Set Up Protection
An early first fall frost won’t hurt your garden if you protect your crops! There are a few options that work with varying levels of success. Mild-climate gardeners may only have to use row covers, while gardeners in northern zones will want to consider adding cold frames or greenhouses to their landscapes.
Row Cover
Row covers protect garden plants from early frosts, birds, and insect pests that thrive under cool temperatures. They’re permeable fabric covers for crops that let water, air, and sunlight through. They’re perfect for the fall garden, working well on raised beds, in-ground beds, and containers. Drape them over the plants, or prop them up with bamboo stakes for tall species.
Three types of frost cloth exist: standard, frost blanket, and extralight. The standard cloth lets 75-85% of the light pass through, and it protects plants from insects and frosts down to 28°F (-2°C). Use it in autumn if you have light frosts throughout the season, and remove it during the day if temperatures exceed 80°F (27°C).
Frost blankets are thick and have less light penetration at around 50%. They protect crops from hard frosts to 24°F (-4°C). You must remove them if temperatures warm significantly, so they won’t protect crops from insects on warm days. Extralight, or summer-weight cloth, only works as an insect barrier during summer and isn’t best for frost protection.
Cold Frame
A cold frame adds more cold protection than a row cover. It has wood and glass or a strong, clear plastic, so it’s sturdy for winter winds. It varies in size from a small square to a large rectangle.
A cold frame consists of a wooden base with a lid that has a clear material. The sealable quality of the lid traps warm air and moisture inside the frame, creating a warm environment amid hard frosts. Use cold frames to winterize tender perennials, sow fall crops, or get a jump start on spring seed starting.
Greenhouse
A greenhouse is the ultimate frost protector! Make one of metal and glass for the ultimate, long-lasting structure. Greenhouses with steel frames and UV-resistant plastic also work well at trapping heat. Some growers call them hoop houses because the metal frames resemble giant hoops.
Greenhouses range in all sizes, from small ones that fit on a porch to giant ones the size of a house. Add on extra machines like fans, humidifiers, and dehumidifiers to create the ideal growing situation for whatever plants you’d like to raise at any time of year.
Water Dry Soil
You may think that cold temperatures kill plants, but what often hurts them in winter is freezing and dry soil! The roots lack moisture to stay turgid, and the plant wilts without proper defenses. Overwatering can harm dormant plants, so it’s important to maintain a balance between soggy and bone-dry.
Container plants are more susceptible to dry, freezing soil than in-ground ones are. Their small containers dry quickly, and the roots wither away. If you have species in containers beneath cover, they’ll need even more water than the others in the garden. Natural rainfall keeps roots moist in autumn and winter, but covers prevent rains from reaching container plants.
Use your best judgment to determine if a plant needs water. An easy trick to use is the finger test. Simply stick your finger in the soil and pull it out. If you sense moisture you don’t need to water, but if it’s dry to the touch, you should irrigate.
Prune Cold-Hardy Perennials
Some plants like pruning during the fall, while others prefer to stay leggy throughout winter. Species like daylilies, smooth and panicle hydrangeas, and lavender benefit from a cutback. The cutting prompts the stems to start sucking in nutrients from the leaves, and it helps them pull their energy into the root zone.
There are a few plants you never want to prune in fall, as you’ll harm their chances of winter survival. Leave cool weather-blooming species alone. Types like chrysanthemums, rhododendrons, and forsythias are actively preparing to bloom or go dormant, and pruning interrupts their natural processes. Do not prune plants that bloom on old wood either, or you’ll risk losing next year’s flowers.
Leave native wildflower species alone, and don’t prune their stems. The hollow, dead stems house insects hiding during the winter, and the seed heads provide valuable nutrition to birds and small mammals that are still active.
Add Mulch or Compost
Bulbs, perennials, shrubs, and trees use their underground roots to stay alive during autumn and winter. They preserve energy, moisture, and nutrients until they need to use them. Add mulch on top of the soil to further protect your precious plants’ roots from an early fall frost while also enhancing the aesthetic of your garden.
An organic mulch like leaf mold, fall leaves, or straw works well, but the best organic mulch is compost. Compost is both a soil and a fertilizer, and it has beneficial attributes that help soils long after you add it. It contains humus, which absorbs moisture and keeps plants happy. It also has plenty of air pockets that help plant roots breathe.
If you can’t find compost near you, try making it! It’s an easy amendment to create, and it helps you recycle waste from your garden, kitchen, and home. Turn food scraps into garden gold by starting a hot or cold compost pile before frost arrives.
Winterize Your Irrigation Setup
Plants aren’t the only part of your garden to protect from an early frost. Freezing weather can rupture pipes! The low temperatures cause water to expand as it turns to ice. This expansion can burst drip lines, sprinkler pipes, and underground irrigation. Prepare your garden before freezing temperatures arrive and you’ll avoid any heartaches from irrigation damage.
Prevent breakages by disconnecting hoses and placing a faucet cover over the faucet. If you use drip irrigation or sprinkler lines, shut off the main line until you need to use it again. Empty the line if possible. Some areas have short winters and you’ll turn it on in a month, while others are more enduring. Wait to turn on the irrigation until temperatures are above freezing for best results.
