Root Crops More or Less Trouble-Free, Produce Lots of Food in a Small Space

by N. S. Mansour and J. R. Baggett.

N. S. Mansour is Extension Vegetable Crops Specialist, and J. R. Baggett is Professor of Horticulture, at Oregon State University, Corvallis.

Root crops are valuable and satisfying additions to the garden because they offer a prolonged harvest season, long storage life, and produce a large amount of food in a small amount of space. With few exceptions, the root crops are trouble-free and do not require the continual care of other kinds of vegetables. They are also adapted to winter storage in root cellars or simple pits.

The table gives general characteristics of some of the root crops.

Root crops are best grown in well drained, loose friable (crumbly) soil. This is especially important because these crops are among the earliest planted and the latest harvested. If the soil is heavy, it may be beneficial to form a raised bed, 4 to 6 inches high and 12 to 24 inches across the top. The width of the top depends on whether 1 or 2 rows are planted on the bed. Use of raised beds reduces soil compaction during the growing season, permits easier digging, and allows carrots and parsnips to attain greater length and be smoother in shape.

Root crops, especially carrots and parsnips, tend to have fewer misshapen roots when grown on beds and will store better in the garden without splitting or rotting. Adding sand and humus to heavy soils will improve soil fertility and permit easier digging and cleaning of roots. However, adding sand without humus can cause a concrete-like condition.

Soil pH (acidity) is usually not limiting. But radishes, turnips, and rutabagas benefit from neutral or slightly alkaline soils if club root disease is present. This disease is inhibited by an alkaline soil condition. You can reduce acidity by adding lime, at the rate of 15 to 20 pounds per hundred square feet of garden area.

A fertilizer rate of 2 pounds of 10-20-10 per hundred square feet of garden area is adequate; additional nitrogen may be required for celeriac. The fertilizer and lime should be thoroughly incorporated in the soil to a depth of 4 to 6 inches. Lime is best applied in fall. Don't use manure where carrots are to be grown, because misshapen roots can result.

Root crops may be planted as soon as the garden soil can be prepared. All have small seeds, which should be planted no deeper than 1/2 inch.

Crusting and drying can be minimized by mulching the seeded row with sawdust or bark dust, or using such materials as vermiculite or washed sand for covering the seeds instead of soil. Water the newly seeded rows frequently, as often as once a day, in order to prevent a crust from forming and to protect the tender seedlings from drying out until they are well established. Consult the table for appropriate thinning and spacing information.

Pests

Root crops do not often require pest control. However, radishes, turnips, and rutabagas can be seriously attacked by the cabbage maggot and control of this insect is important. The best prevention for the pest is treatment of the soil before planting with a suitable soil insecticide. This material can be spread over the garden area and gently raked into the top 1 or 2 inches of soil. Take care not to mix the insecticide too deeply into the soil since this will dilute it and reduce effectiveness.

You may need to drench turnips and rutabagas with an insecticide four to six weeks after planting, since the soil treatment can wear off by that time.

Control of aphids and flea beetles may sometimes be necessary.

Always consult the labels for application details of any pesticide.

Use of weed control chemicals is not feasible in most home gardens. Mulches are useful in reducing weeds after the crops have been well established. They are also useful in improving the color of carrots by preventing the green discoloration normally seen at shoulders of the root. Turnips and rutabagas should not be covered with a mulch if the typical purple color of the upper part of the root is desired.

Radishes are a quick and easy crop to grow in a small space.

There are usually no serious disease problems. The club root disease of radishes, turnips and rutabagas occurs only occasionally in gardens. Beets are sometimes seriously affected by canker, a non-parasitic disorder that occurs when there is boron deficiency in the soil.

Fungus and virus diseases of root crop foliage occasionally occur, but it is generally not necessary nor feasible for the gardener to attempt control.

Most root crops can be harvested over a wide range of maturity. Beets can be harvested when small or allowed to mature fully, and carrots can be used from pencil size to full grown over a period of three to six months. Spring radishes, a fast growing crop, are usable over a very short period. See table for days to maturity and harvest duration. Root crops often Must be thinned if they are to mature Properly and in the right length of time.