Growing fall vegetables presents somewhat different challenges than growing spring vegetables. Summer drought, heat and insects can affect planting in late summer for a fall harvest. However, container gardening offers you some flexibility that may come in handy when growing your fall vegetables. You may have to water more often, but you can control soil temperature and sun exposure much more easily with containers.
Choose seeds for vegetables that grow well in cool weather and/or are frost tolerant. Dark leafy greens, carrots, leeks, onions and members of the cabbage family are all good choices. If growing root vegetables choose appropriately sized containers. Small varieties of some vegetables are available that may be better suited to your containers.
Fill containers with soil and compost in a 1:1 ratio. Pre-water the soil before sowing your seeds to ensure there is adequate moisture for germination.
Sow seeds for fall vegetables directly in the containers, about 1/4" deeper than the package suggests. Package planting depth suggestions are intended for spring planting, and extra depth is necessary to germinate in fall. Unlike spring vegetables, there is no need to sow seeds indoors and transplant them outside later.
Fertilize according to package instructions. Even if you previously used your containers earlier in the year and applied fertilizer at that time, fall vegetables will require more. Nitrogen is especially important.
Water fall vegetables regularly. Containers require more watering than traditional garden plots, and seeds you start in late summer for fall harvest need the most water of all. Late summer is usually the hottest part, and good vegetable yields require consistent watering.
Mulch your vegetables to a depth of 2 to 3 inches once the seeds have germinated. Mulch helps to retain water, and also helps to maintain a consistent temperature. Think of it as a blanket for your plants.
Use floating row covers (cloth made specifically for shielding tender garden plants from temperature extremes) when the weather forecast in your area predicts frost overnight. Many dark leafy greens, such as kale, do quite well after the first frost. Other vegetables are more sensitive to it. By using floating row covers, you can keep them insulated.