Know Your Gardening Zone
Fall gardening is much more than raking leaves. Take advantage of crisp fall days to harvest fruits and vegetables, plant new seeds and bulbs, and prepare the garden for next year. Schedule fall harvest and planting based on your gardening zone, which is determined by average high and low temperatures, as well as microclimate, precipitation and soil.
Autumn technically begins at 3:09 GMT Sept. 23 this year, but the start of fall varies widely for gardeners. The USDA hardiness zone map is a good place to start defining your fall gardening zone, but it doesn’t tell the whole story. The psychedelic 11-zone map is based on average winter minimum temperatures. This makes it a fairly good indicator of which plant types will survive in a given area. However, it is less useful for knowing when to harvest and plant in the fall.
Summer high temperatures and winter precipitation are other important considerations. Austin, Texas, and Portland, Oregon, are in the same hardiness zone. Portland’s wet winters can leave the ground too soggy for healthy planting in the early spring. On the other hand, Austin’s hot summers may be too harsh for early fall planting. Late fall or early spring may be better.
Soil quality also makes a difference. Heavy, clay soils should be turned in the fall to allow winter frosts to break up clods before spring. Also consider sprinkling garden lime or gypsum on the soil to encourage healthy spring soil. More fertile soil should not need much attention in the fall.
Fall gardening tasks
Here is a partial list of fall gardening tasks, with additional tips for some gardening zones.
- Start harvesting tomatoes, corn, peppers, eggplants and other vegetables early in the fall. In colder climates, an early frost can threaten tomatoes in particular before they have a chance to fully ripen. Consider picking fruit that has just starting turning from green to pink. Remove stems, wash and dry the tomatoes and leave them inside on absorbent paper towels to ripen.
- Plant trees early. Late summer or early fall is the best time to plant trees, allowing them to establish roots before winter. Wait until the hottest weather has passed, but before the soil freezes. An exception is evergreens in cold, harsh climates. Their needles will be exposed to winter elements while they are young and weak. Make sure to mulch around trees deeply in the fall, and water throughout the winter.
- Plant bulbs throughout the fall. Early spring flowers such as hyacinths can be started early in the fall, and tulips can go in any time the soil is below 60 degrees at six inches below the surface. All bulbs must be planted before the soil freezes.
- Cut back perennials and clean up leaves — or not. In wetter, warmer climates, you can trim back perennials to the stem and clear all the leaves for a pristine garden. In cooler, drier climates, you may want to forego perceived aesthetic perfection for practicality. Dried foliage helps insulate the soil, and fallen leaves can be a healthy, beneficial mulch. Take care, however, when raking thick piles of leaves from the lawn into shrub beds. A mat of flat leaves can smother ground covers and other small plants.
Finally, consult your local cooperative extension office for more information on your gardening zone and to determine the best time for fall planting and harvesting. Click here for a directory of cooperative extension offices.