A steady, cool, pelting rain signals autumn and the end of the summer garden season. It invites a twinge of loss—the end of ripe tomatoes and glossy eggplants—and a reprieve from biting insects and leathery, sunburned skin. But work is not complete. It’s time to rip out withered tomato vines and powdery mildewed squash plants, consider a mulch or cover crop and survey the garden for winter endurance.
Autumn commands our attention as attentively as spring, but without the feverish anticipation of what’s to come. Instead, we size up the past, review our triumphs and mistakes, assess changes for next year, and plant fall crops. More urgently, it’s time to consider how to prevent erosion and add nutrients to a well-used plot.
Cover crops, or green manures, as some call them, will prevent topsoil from blowing away and provide a hefty dose of nitrogen for a spring garden. Choose the kind of cover crop that works best for the soil and winter conditions where you live. In a short, brutish season, annual rye is a favorite. It germinates and grows quickly. Almost in the time you’ve turned your back, it’s an emerald green carpet. Come spring, turn the thick thatch over and rye’s leaf tips add nitrogen and humus to the soil. It’s a top choice against soil erosion because the carpet of grass grows so thickly that it withstands severe winds. But come spring, that carpet may be so densely packed that it’s toil and trouble to turn over.
That’s why other gardeners choose a legume: clover, vetch, alfalfa or beans. Legumes add nitrogen to the soil via the root nodules that have adapted to self-fertilize. We cash in on that botanical marvel by planting legumes and letting them enrich our plots. But they will take longer to germinate and grow. If winter winds are howling outside, legumes never will grow fast enough, or perhaps not at all, to cover space quickly. Still, some gardeners are planting legumes such as red or white clover and never disrupting the growth. They simply plant vegetables in their healthy clover patch, yank up the veggie plants after production and clovers continue throughout the autumn. As long as the soil is completely covered from winds, this method is an easy choice. Alfalfa produces extraordinary amounts of nitrogen and its deep roots protect against drought conditions. At the same time, pulling up those roots may be nearly impossible. Even so, whether grown in the soil or spread about in pellet form, alfalfa is one of the top organic nitrogen fertilizers available.
Another method works well to establish a new garden for spring planting. Place cardboard on the patch of ground you’ve selected. Layer compost, leaves and heavier mulch on top. Water this layered mix well and keep it watered during dry winter spells. You’ll have a perfect composition in which to plant come spring. In the same manner, some gardeners layer composted manures, leaf or mushroom compost, grass clippings and dead leaves to winter over. The one hazard with this approach is a tendency to blow away during a sudden dry and windy spell. So choose a protected place, or at least a place that is easily watered during a winter month that brings little rain or snow.
That takes care of the vegetable gardens. Ornamental and perennial fruit gardens require a different approach. Years ago gardeners were advised to cut back perennials to their basal growth. No longer. Now there’s a far more relaxed approach. In some cases, you may want the seed heads to self-seed and renew the plants. In any case, seed heads offer food for winter birds. The bent, sprawling stems and leaves will be protective for new basal growth when cold winter winds whip up and down the Front Range.
Most perennials will benefit from a spring clean up rather than a fall removal. This is true for cutting back ornamental grasses, too. And both crabapple and apple trees generally are pruned in midwinter to mitigate fire blight, a destructive bacterium most active in warm weather.
Add mulch to bushes and shrub roses, shredded bark or coconut hulls, any quality organic mulch that won’t blow away. Our soils heat up in the day and freeze by night, which taxes any growing shrub. Several inches of mulch helps to moderate some of these extreme changes and also conserves water in dry winters. We’re advised by experts to water our trees and shrubs if a month has passed without any snow or rainfall. But only after temperatures exceed 40 degrees. The idea is to prevent water from pooling into an icy ring around a shrub. At 40 degrees, water should sink into the ground a bit. Even though many plants are dormant, their roots continue to need some water throughout the winter.
The final touch is to collect leaves, yard clippings and veggie scraps for the compost pile. After a long winter the compost is ready for spring, either as a mulch or compost. You’ll be surprised how grateful you’ll be when you can fork out half-composted mulch from your pile to protect new spring transplants. What gets banked in your winter pile becomes gold by May. And, as an added boon, not a scrap has left the premises for a landfill unless you’ve pulled up diseased plants. Those can be thrown away.
If you cannot bear to plant nothing for the late winter, early spring, consider two excellent crops. Spinach seeds planted in late fall will get the jump on any other vegetables by early spring. And garlic, too, can be planted just like other fall planted bulbs. But you won’t harvest them in the early spring. Instead, wait until mid-July when they will reach their peak and reward you with healthy, giant garlic cloves to store for a year.
Summer may be over but planning for next year has just begun.