In autumn, we often think more of football games, pumpkins, and a cozy sweater than we do about the garden. The garden starts to look a bit ratty, and after a long summer of weeding and harvesting, we have other pursuits in mind. But keeping many of our favorite greens going well after the first chill in the air is easier than you might think, and well worth the effort.

Fall gardening is rewarding and low-key. There's less maintenance and less stress. Many cool-season greens not only tolerate light frosts (28-32°F) but actually improve in flavor after exposure to cold temperatures. Kale after a frost is almost a different taste and texture entirely from that harvested in summer. A gardener whose first frost is normally in early October might well keep lettuces, spinach, kale, chard, and asian greens growing until nearly Thanksgiving. Kale might go until New Year's, depending on the weather. 

If you haven't tried making an after-the-frost kale, garlic, and olive oil pasta sauce, you're missing out on a bright and easy way to enjoy this super cold-hardy green. Fresh harvests of greens continuing well into winter have you getting hungry? Check out these tips.

What are cool-season greens?

Many of our garden crops do their best in cool weather, be that in spring or fall. Lettuces, peas, kale, spinach, turnips, radicchio, chard, Asian greens, radishes, Brussels sprouts, and more all thrive in cooler temperatures and dislike the hot, intense summer sun. Crops such as lettuce and spinach are quite prone to bolting in the summer, making them difficult to keep in good condition, but they shine in the shoulder seasons.

Many greens, such as kale, spinach, collards, and mustard, can survive multiple light frosts and continue growing whenever temperatures rise above 40°F. 

Is it too late to start cool-season greens?

The latest planting date will depend on two factors: your first fall freeze date and whether you plan to provide fall protection in the form of caterpillar tunnels, plastic coverings, or a cold frame. 

Most of the cold-season greens we grow in autumn are tolerant of mild frosts, and some are hardy even after snow covers the ground. However, they'll grow more slowly once the temperatures start to drop below freezing at night. For fall greens, we can use the approximate date of our first frost as a starting point, and then count backward using days-to-maturity plus a fall slowdown buffer. 

Harvests will continue past the first fall frosts, but the plant should be nearly at harvesting size by then. If your spinach takes forty days to mature, count back about six weeks from your first frost date and try to get the spinach started by then. 

As the days shorten and temperatures drop, most greens stop growing quickly. They'll still grow on warm days, but won't increase in size as rapidly. Of course, if you’ll be using a cold frame, you can plant much later in the season.

How to keep fall greens growing

To keep your fall greens in peak condition and production, we care for them a little differently than in summer. Plants grow more slowly in cold weather, but for these plants, growth doesn't stop at first frost, and the results are well worth it.

Do a little easy weeding

One of the joys of fall gardening and growing greens is that you rarely have much weeding to do. Annual weeds have pretty much run their course by early autumn. Perennial weeds, however, can take over if left unchecked, and it will not only slow growth of your greens, but cause additional problems in spring. 

Give those perennial weeds a yank as you come across them. The weather is pleasant, and it doesn't seem like too much of a chore to give that piece of crabgrass a tug and toss it. Often, the stems are more rigid and wiry, and it can be easy to get the entire plant, root and all.

Use mulch

Mulch can help keep the ground warmer in cold weather, extending the growing season for your plants. Straw is my favorite for autumn use, and by then, it is readily available. Unless you have a very large fall garden, a bale or two will likely be all you need. A little mulch, with no other treatment, has helped my kale survive occasional nights in the single digits.

If slugs are a problem for you under mulch, use some slug bait or set out beer slug traps. You can also lay down a piece of cardboard or an old hunk of plywood overnight. Slugs will congregate under the wood, and can be picked off the next morning.

Frost covers and row covers

Tender fall greens, such as mustard and some lettuces, can be protected from moderate frosts by a layer of frost cloth. A few single plants can be quickly covered, and the edges of the cloth held down by a rock or brick. 

A row or bed of greens can be sheltered by creating a caterpillar tunnel out of flexible PVC or bamboo, and draping the frost cloth over that. Again, hold down the edges with soil or a heavy object. It's the trapping of heat that protects the plants, and if the edges aren't held firm at the ground, that heat is lost out the sides. 

Row covers can be rolled back or removed on warm, sunny days to allow for unimpeded sunshine and ventilation, then replaced before cold weather. Don't forget to provide some support for the fabric, as it can become heavy with rain or dew and break plant stems.

Remember to water

Depending on the weather, autumn and early winter can be either unceasingly wet and gloomy or rather dry. Since the temps are cooler and plant transpiration is less, good drainage is important. If you’re growing cool-season greens in containers on the deck, that shouldn't be a problem. However, for in-ground growing, be sure to select a spot with good drainage. All too often, areas that were adequate in summer will become soggy or even have standing water in fall and early winter, due to more frequent rains and less plant uptake to pump the soil dry. 

That said, don't forget to water as needed. Just like it’s easier to remember to drink a glass of water when you're hot, the reverse also applies. It's easy to forget to water the fall garden when we're wearing a sweater and thinking of hot cider. Checking the soil moisture with your finger and providing water as needed (it won't likely be as often) is important for encouraging good, lush growth. When it is time to water, do so in the morning and keep an eye on the weather forecast. You don't want to water just in time for it to freeze overnight.

Try growing in cold frames!

For those who truly want to keep their greens thriving this autumn and winter, a DIY cold frame is the way to go. Cold frames can be made from various materials, but the basic idea is to create a miniature greenhouse that keeps the soil warm and protects plants from frost. As an added benefit, you can design it to be rabbit and deer-proof. 

Cold frames can be made out of straw bales, wood, bricks, or anything else you might bang together to build a base. Most are rectangular or square, but the shape isn’t important. The top needs to be clear, or mostly clear, to let in sunlight, and you need to be able to lift it to access the plants and for ventilation on hot days. The entire cold frame should be pretty weather-tight to prevent the warm air from leaking out at night. 

A cold frame located in a sunny spot can keep kale and other greens thriving well into winter, even in northern regions. Those with moderate winters may be able to keep greens going right through the cold months. Once spring arrives, your cold frame is an ideal spot for some early spring crops. The warmer soil and air inside the coldframe can add several weeks or even months to your spring gardening season.