Cold tolerance is the bright line dividing Fall Vegetables—like broccoli, spinach, and lettuce—from Summer Vegetables—like tomatoes, melons, and cucumbers.Cruciferous vegetables like broccoli, cabbage, cauliflower, kale, collards, and Asian greens.In warm-winter climates, fall vegetables planted in early September grow slowly through the winter months, then size up quickly as soon as the weather warms up in the spring.After germinating, carrots, spinach, and broccoli form a low rosette of leaves radiating out from the center.As long as conditions are good—steady water, decent soil, temperatures in the 60’s and low 70’s (16-23° C)—fall vegetables accumulate and store nutrients.Harvest leafy fall vegetables at the first sign of a flower stalk, while the leaves are still succulent.Steady water encourages continuous, succulent growth, and reduces the stress of high temperatures.When growing fall vegetables, mix 2-3” (5-8 cm) of good garden compost or well-composted manure into the soil at planting time.Plants grown for their stalks and green, leafy vegetables are heavy feeders, and need supplemental fertilizer.Broccoli, cabbage, cauliflower, kale, spinach, Swiss chard, fennel, and celery—all need a little extra nitrogen for the best yields.Worm castings, fish meal, and composted animal manures are good choices when temperatures are cool.Root crops like carrots, parsnips, and beets do not need supplemental nitrogen.Cool-season legumes like peas and fava beans also need no supplemental nitrogen—although they do like organic matter in the soil.For these plants, soil nitrogen inhibits the nitrogen-fixing ability of the Rhizobia bacteria that colonize their roots, reducing the amount of free fertilizer they supply to your garden.Overhead watering in the heat of the day cools the leaves and soil, in addition to providing needed irrigation.It drops both daytime and nighttime temperatures into the 55-65° (13-18° C) groove that fall vegetables thrive in.Unlike cool-season vegetables, frost kills them, so in the northern hemisphere, they’re planted as summer annuals.Nightshades (tomatoes, peppers, eggplants, and potatoes), cucurbits (cucumbers, melons, squash), beans, and corn fall into this group.Most summer vegetables need a long growing season to produce the most fruit.Northern and alpine gardeners need to start seeds under lights indoors about 8 weeks before the last frost date for their area, or purchase seedlings from local nurseries to set out after all danger of frost is passed.Summer vegetables are heavy feeders and need supplemental nitrogen, especially during the first part of the growing season.The idea is to have large, robust plants with a lot of leaf area when it’s hot enough for summer vegetables to flower and set fruit.Kelp Meal supplies potassium, as well as trace minerals that help boost plant immunity.Plant diseases that plague many summer vegetables spread readily on wet foliage.Tomatoes, peppers, and eggplants all need caging or staking to support the plants when they’re heavy with fruit.I’ll bow to produce aisle usage and refer to these fruit as vegetables, but the distinction is important.It’s important because the ancestors of fruit and vegetable plants evolved under different soil conditions, and if we’re growing our food without chemical props, we can start by understanding how the natural world operates without them.Fall vegetables evolved from weedy grassland ancestors in thin, bacterially-dominated soils.The threadlike hyphae of the fungi connect to the plant roots, plugging them into a vast underground network that can run for hundreds of yards underground, all of it threaded together into a single organism that can transport nutrients anywhere in the network.After all, gardeners can amend the soil with colloidial phosphate and greensand to supply phosphorus and potassium to fruiting plants, so they don’t have to rely on mycorrhizal networks.And in frequently tilled gardens, where the fungi are continuously broken up by cultivation, this is a good way to supply them.Summer vegetables and fruit evolved absorbing phosphorus and potassium with the aid of soil fungi.
Edward R. Forte
Author