Now, before the first frost, is the time to visit your local garden center and buy perennials at clearance-sale prices. They may look a bit reedy, but there’s nothing wrong with them, and perennials planted in the fall have all fall and winter to acclimate and root. Most perennials, from herbs to flowers to grass, go on sale at the end of the summer.
Plant Spring-blooming Bulbs – Fall is the right time to plant hardy, spring-blooming bulbs. Do it sooner rather than later, because if the soil is drenched with rains or freezes, your rehabilitation project will be difficult. Buy large, firm bulbs and plant them at the depth recommended by your garden store –general advice is to sink them to a depth of two or three times their diameter. If you have a problem with rodents, put gravel in the planting hole or wrap the bulbs before planting. Straw is an attractive nesting material for rodents, so do not use it as a mulch around bulbs.
Dig and Store Bulbs and Corms – In cold-climate areas, fall is when gardeners rescue the bulbs and corms of the tender summer plants – caladiums, cannas, dahlias – which will freeze and die if left in the ground over the winter. Dig them up when their foliage turns brown; trim off the remaining foliage or flower stalks, let them air-dry for a week and then layer them in paper bags filled with peat moss or vermiculite. Store the bags in a cool, dark place, such as a basement or cool closet. If the storage area is humid, dust the bulbs with the organic fungicide sulfur before bagging them and slit the bags for better ventilation. Check the bulbs monthly; discard any that look soft and sprinkle water on those that look shriveled.
Protect Plants from Winter Stress – Winter dormancy is not always a blessing for gardeners, starting with the fact that frozen ground locks up water, injuring and even killing dormant plants. Give your plants, from perennials to trees, a good, long soaking before the soil freezes in late fall. Protect shrubs and roses by wrapping them loosely in burlap, covering them with a fence-wire cage that is stuffed with dried leaves or straw.
Plan Massive Cutbacks
Because pests and diseases thrive in soil and dead plant material, it’s important to remove what’s left of your garden’s annuals and vegetable plants now, as the daylight shortens and temperatures drop. Here’s a punch list of cutbacks; let the cleanup begin.
Perennials – Cut back the dead and dying foliage to just a few inches above the ground; this will not harm the plants, whose roots will survive for next year’s comeback, even as aboveground growth dies.
Annuals – Annuals do not come back, and there is no reason to leave any part of these plants in the ground.
Vegetables – Many gardeners pull their annual vegetable plants out of the ground every fall, but here’s another idea: Chop the main stem a few inches aboveground, and put whatever foliage that remains into the compost bin. Leaving roots in the ground helps to prevent erosion; as the roots decompose, they add nutrients to the soil.
Compost – Compost only pest-free and non-diseased plants; make sure to destroy any plant material and pathogens, to prevent the return of insect pests next year. The less hospitable your garden is to winter pests, the fewer problems you’ll have next spring. Be ruthless.
Keep a Record – Now is the time to document what was growing in your garden this year, with photographs and careful notes. Careful record-keeping helps gardeners avoid injuring dormant perennials and remember what worked, and what didn’t, this year.
Spray Now for Pests – Many damaging insects become active in early spring, before gardeners have time to take action against them. Drenching the soil now with systemic insecticides leaves active ingredients for next spring, when pests begin to feed again.
Bring Delicate Plants Indoors – Bring in herbs (thyme, rosemary, basil) and hot pepper plants for the winter; they’ll do best in a south-facing window.
Evaluate – It’s never too soon to start planning next year’s garden. Evaluate what worked and what didn’t in this year’s garden; consider sketching a plan for your garden next year. As winter lingers, buy seeds and start growing them indoors.