FALL IN! - HORTICULTURE'S GUIDE TO FALL GARDEN TASKS

When summer's heat begins to recede, it's time to take up our tools and make the best of the rest of the gardening year. Tackle those tasks with this review of frequent questions and favorite advice pertaining to autumn.

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Q WHY DO WE PLANT IN FALL?

A In the fall, the soil is still warm, so roots will continue to grow. Plants installed in early spring, meanwhile, get off to a slower start because the soil hasn't yet warmed to optimum temperatures for root growth. Fall planted plants begin root growth more quickly the next spring, and top growth follows sooner.

Additionally, fall plantings do not have to contend with the stress of summer heat and potential drought. The season's cooler daytime temperatures are gentle on plants as they get established, and the slant of the sun is less harsh. Pests and diseases tend to be less prevalent in the fall, as this year's bugs die or prepare to hibernate and the humidity that promotes many diseases fades away.

Fall favors the gardener, too. Successes and failures of the summer are fresh in mind to inform new plant choices and placement. The work feels more pleasant in the cooler air, and the garden center might be running an end-of-season sale.

Q WHAT AND WHEN DO WE PLANT IN FALL?

A Fall is the time to plant trees, shrubs, perennials, spring-blooming bulbs and even certain seeds (more on that later).

The best time for fall planting woody plants and perennials is about four to six weeks before the expected first hard frost. Give perennials and evergreen trees and shrubs, which prefer slightly warmer soil temperatures for root growth, the full six weeks. Deciduous woodies can get by with a shorter window.

In the coldest zones, this timeline means "fall planting" should occur in mid-August-really it's late-summer planting! In the warmest zones, where the ground doesn't freeze solid, plant when the hottest, driest weather is behind you and the rainy season is beginning-usually October or November.