Fall Vegetable Gardening
13 August 2007
Virginia Cooperative Extension, Charlottesville/Albemarle County Office
460 Stagecoach Road, Charlottesville, Virginia 22902
phone: 434.872.4580 fax: 434.872.4578
By planning and planting a fall vegetable garden it is possible to have fresh vegetables up to and even past the first frosts. At the time of year when retail vegetable prices are on the rise, you can be reaping large and varied harvests from your still-productive garden site.
Many varieties of vegetables can be planted in mid- to late summer for fall harvests. Succession plantings of warm season crops (such as corn and beans) can be harvested up until the first killing frost. Cool season crops (such as kale, turnips, mustard, broccoli, cabbage) grow well during the cool fall days and can withstand light frosts. Timely planting is the key to a successful fall garden.
To determine the time to plant a particular vegetable for the latest harvest in your area, you need to know the average date of the first killing frost and the number of days to maturity for the variety you are growing. Choose earliest maturing varieties for late plantings. The formula below for determining the number of days to count back from the first frost will help determine when to start your fall garden.
Number of days from seeding or transplanting outdoors to harvest
+ Number of days from seed to transplant if you start your own seed
+ Average harvest period
+ Fall Factor (about two weeks)
+ Frost Tender Factor (if applicable) (two weeks)
= Days to count back from first frost date
The Frost Tender Factor is added only for those crops that are sensitive to frost (corn, beans, cucumbers, tomatoes, squash), as these must mature two weeks before frost in order to produce a reasonable harvest. The Fall Factor takes into account the slow growth that results from cool weather and short days in the fall, and amounts to about two weeks. This time can be reduced from 2-5 days by pre-sprouting seeds. Almost any crop that is not grown from transplants can benefit from pre-sprouting. Sprout seeds in doors, allowing them to reach a maximum length of one inch. Sprouted seeds may be planted deeper than normal to help prevent drying out, and they should be watered well until they break the soil surface. Care should be taken not to break off the sprouts when planting them.
Before you plant fall crops prepare the soil by restoring the nutrients that were removed by spring and summer crops. A light layer of compost, aged manure, or a small application of complete chemical fertilizer will boost soil nutrients in preparation for another crop. Dry soil can make working the soil difficult and inhibit seed germination during the mid-summer period. Plant fall vegetables when the soil is moist after a rain, or water the area thoroughly the day before planting. Seeds may be planted in a shallow trench to conserve moisture. Cover the seeds about twice as deeply as you do in the spring. An old-time trick for germinating seeds in mid-summer is to plant the seeds, water them in well, and then place a board over the row until the sprouts just reach the soil surface; at that time remove the board. Plastic, especially black plastic, may cause the soil to get too hot. In severe hot weather a light, open type of mulch, such as loose straw or pine boughs, may be placed over the seeded row. This must be removed as soon as the seedlings are up so that the seedlings receive full sun. Starting transplants in a shaded cold frame or in a cool indoor area is another possibility. A thin layer of organic mulch helps retain soil moisture and keeps the soil warm without deterring germination.
Once young plants are established, a heavier layer of mulch can be used to hold moisture and control weeds. Irrigate when necessary so the young plants have sufficient moisture. Fall plantings often have fewer insect problems, as they avoid the peak insect activity period of midsummer. However, some insects, such as cabbageworm and corn earworm, may be even worse late in the year than in summer. Avoid some pests and diseases by planting crops of different families than were originally in that section of the garden.
Some of the best quality vegetables are produced during the warm days and cool nights of the fall season. These environmental conditions add sugar to sweet corn and crispness to carrots. Parsnips and Jerusalem artichokes are examples of crops that are distinctly improved by a touch of frost.
The fall garden gives you a chance to try again any crops that failed in the spring. Some crops, in fact, grow well only in the fall in certain areas. Cauliflower and long-season Chinese cabbage are two examples of crops which do not produce well in Virginia's mountain areas in spring because they cannot reach maturity before the cool weather ends.
Protection of vegetable plants during cold periods can extend your season even further. Though in the hot days of summer the last thing you want to think about is planting more crops, look ahead to the fall garden, which offers its own satisfaction through its prolonged harvest of fresh vegetables, savings in food costs, and the knowledge that you are making full use of your gardening space and season.
This fall Virginia Cooperative Extension will be offering Master Gardener training in Charlottesville. For more information, call (434) 872-4580.
For more information about this and other landscape topics contact your local Virginia Cooperative Extension office. The local Virginia Cooperative Extension office numbers are Albemarle 872-4580, Fluvanna 591-1950, Greene 985-5236, Louisa 540-967-3422, and Nelson 263-4035.