Fall is Good for Root Growth
In the fall, the perfect combination of warm soils and milder weather create ideal conditions for newly planted trees, shrubs, and perennials. Warm soil temperatures encourage root growth – more so than in the spring when the soil is still warming up.
Autumn is a great season for annuals, low-maintenance perennials and evergreen shrubs to shine. In fact, some of the most popular flowers, like colorful mums, roses, dahlias, purple pansies and yes, even bright yellow sunflowers, all bloom around September and October.
Although each plant's needs may vary and some will be more winter-hardy than others, in general about a month before the last fall frost is sufficient in giving the plant enough time to establish itself and take root.
"Fall is an excellent time to plant almost any perennial, with the exception of many ornamental grasses, which are better planted in spring," says Erin Schanen, Troy-Bilt's gardening partner, a master gardener volunteer and creator of The Impatient Gardener blog and YouTube channel.
Mid- to late-August is often an excellent time to plant fall flowers, as long as the weather isn't still so hot that the plants will suffer heat stress. But don't wait too late to plant, or you'll have a very short window to enjoy your flowers. Check the growing requirements for each plant.
Still, some other plants can grow in mild winters. Root vegetables like garlic, carrots, and radishes grow well in cold temperatures. So do leafy greens like collards, kale, and cabbage. However, even most cold crops grow best if they're protected from frost and freezing temperatures.
In general, aim to finish your fall planting about 6 weeks before your first expected frost date (8 weeks for evergreens). In Zones 3 and 4, you would count back from the latter half of September.
Mid-August to mid-October is an ideal time of year to plant new trees, though, that time frame can be stretched into November and December. To be 100% sure, measure soil temperature early in the morning for a few, consecutive days. If your soil is consistently 50° F or higher, you're good to plant.
Don't put down those garden gloves for the year just yet! Believe it or not, October happens to be one of the most fruitful times of year to plant spring-blooming bulbs, hardy vegetables, and shrubs of many varieties.
If you live in a frost-free region, October is a great time to plant cool-weather flowers and vegetables in your garden. Crops such as kale, cabbage, collards, lettuce, carrots, mustard, onions, Brussels sprouts, cauliflower, beets, and garlic can all be planted in early to late October.
Gardening in the fall provides a longer period with more 'good' days, as compared to the often tumultuous spring season. Plus, if you plant in fall you'll end up ahead of the game and won't have to rush to get everything done after winter. In fact, a good strategy is to plant perennials when you plant your fall bulbs.
Asters. These beautiful fall-flowering perennials are a lovely companion planting to chrysanthemums, the other stars of the autumn garden. Give asters full sun, and water to get them established (but don't overdo it; they don't like soggy feet).
You can transplant perennials anytime until the ground freezes in the fall, or wait to transplant them in the spring. Fall is an excellent time to transplant herbaceous perennials because your plants will then have three seasons to establish a good root system before hot summer weather sets in next year.
Planting in September
Plant now beets, broccoli, Brussels sprouts, carrots, cauliflower, celery, fava beans, kale, kohlrabi, leeks, both head and leaf lettuce, mustard greens, onions, parsley, peas, potatoes, radishes, rutabagas, spinach, Swiss chard, and turnips.
The latest time to plant for most vegetables would be the second week in June with a short harvest time. If planting crops that mature within 50 days, you could plant those as late as the last week in June, but keep in mind the weather will be turning cooler, especially at night. Cool crops are best for late plantings.
Look for deals on spring-blooming bulbs, perennials, trees, and shrubs, which can all be planted in the fall, up until your area gets hit with a hard frost. And don't forget your lawn; cool-season turfgrass can be seeded this time of year, too.
Fall and winter gardening turns your vegetable plot into a giant refrigerator. During the fall season, cool weather allows crops to hold longer in the garden once mature. Crops like broccoli, cabbage, and kale can live for months in the garden after they reach maturity.
Plants like chrysanthemums, nasturtiums and asters are wonderful choices for seasonal planting arrangements. While perennials that will survive the winter are great choices, autumn is also a great time to explore new ideas will short-season annuals too.