Fall Root Crops for the Home Garden

S. Cory Tanner,
Extension Agent -Senior Associate,
Clemson University Cooperative Extension Service

HTG 0817

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Heading into August, many garden veggies have mostly fizzled out. Instead of letting weeds grow in the space left behind, consider planting fall vegetables. A number of cool-season crops can be planted in late summer, and several root vegetables grow particularly well during the fall.

Carrots, rutabagas, beets, and turnips are tasty and nutritious root crops that are planted from late July through early September. These crops perform best in a loose, deep, loamy or sandy soil with plenty of organic matter. Root vegetables will grow in heavy clay soils, but their roots will be smaller and misshapened.

Carrots grow well in the gradually cooling months of fall.
Carrots grow well in the gradually cooling months of fall.
S. Cory Tanner, ©2017, Clemson Extension

When preparing space for fall crops, take time to clean up the planting area well. Remove withered plants from the earlier crop and pull out as many of their roots as possible. Plants that were generally healthy can be added to your compost pile. But, if they were afflicted with some disease or insect pest, then it is wise to bag and send them away with the garbage. Also, remove any rotten fruit, stems, or leaves and pull all weeds from the planting area. Cultivate the cleared soil with a rototiller or spading fork to loosen the soil and break-up any clods to ensure a smooth soil bed that is free of stones and other impediments.

Your work will be lessened if the soil was well prepared earlier. If you followed soil test recommendations for fertilizing and pH adjustment in the spring, then you may only need a light application of nitrogen fertilizer, such as calcium nitrate or blood meal. If you don’t know the nutrient status of your soil, a soil test will provide you with prescription-like recommendations of how to optimize the soil for these crops. For new planting areas that haven’t been soil tested, mix in 3 pounds of 5-10-10 or similar fertilizer per 100 square feet before planting. Of course, tilling in a layer of compost will also benefit the garden soil.

No need to transplant these vegetables, as they can be seeded directly into the garden. These seeds are very small, and it is easiest to scatter them in narrow bands. To get a good stand you should sow the seeds rather thickly, and thin the seedlings later. Banded rows should be at least a foot apart for carrots, beets, and turnips and up to 3 feet for rutabagas.

Many soils in South Carolina form a crust on the surface that can hinder the germination of small seedlings. To avoid this problem, cover your seeds with a manufactured potting soil instead of garden soil. Carrot seeds are covered ⅛-inch deep, but ½-inch for the others. Be sure to keep the seed bed damp during germination with daily waterings. You will lose your crop if the tender seedlings dry out.

When the seedlings are 2 inches tall, thin carrots and beets until there are 2 to 3 inches between plants. Turnips and rutabagas should be thinned to 4 to 6 inches apart. Thinning seedlings can seem wasteful, but it’s absolutely necessary for sizeable roots to form. You can make use of all but the carrot thinnings by washing and adding them to a salad or stir-fry.

Cover small seeds with potting mix to avoid soil crusting  that can inhibit germination.
Cover small seeds with potting mix to avoid soil crusting that can inhibit germination.
S. Cory Tanner, ©2017, Clemson Extension

Root crops are moderate feeders and will need to be side-dressed with a nitrogen fertilizer once the plants are about 4 inches tall. Keep fertilizer 3 inches away from the seedlings to avoid burning their young roots. Alternatively, a liquid fertilizer applied at 1 to 2 week intervals will also work. But, avoid over-fertilization, which will hinder root development.

The garden soil should stay uniformly moist for the best roots. Irrigate plants during periods of dry weather, especially as the roots are developing, by moistening the soil to 6 inches deep.

Edible roots will begin developing 6 to 8 weeks after planting. You can harvest tender roots as early as you like, but oversized roots may become tough and woody. Carrots are typically harvested when their roots begin to show above the soil; beets when they are 1 to 2 inches in diameter; turnips when 2 to 3 inches across; and rutabagas when softball-sized. All of these crops will store for months in plastic bags in the refrigerator, allowing you to enjoy homegrown produce all winter long.

These turnip seedlings have reached 2 inches in height and  are ready to be thinned for optimal root development.
These turnip seedlings have reached 2 inches in height and are ready to be thinned for optimal root development.
S. Cory Tanner, ©2017, Clemson Extension

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