Garlic is a garden specialty that can be successfully grown in Illinois. It does however take some advance planning. It is a long season, over-wintered crop, with planting best done in the fall months for a bountiful harvest next summer.
Like flower bulbs, garlic and its close relative, elephant garlic are perennial bulbs. When fall-planted, garlic cloves will root and make limited growth before the first hard freeze. In the early spring, growth resumes, bulbs and eventually seed stalks form, then the tops die down in early summer. Garlic can be spring planted, but an internal chill requirement must be met for the cloves to properly grow. Thus spring planted garlic should be stored in the refrigerator for at least 8 weeks prior to planting to ensure proper chilling. Fall-planted garlic will obtain its chilling in the soil and has the advantage of gaining fall root growth and earlier maturity. If properly planted, cold temperatures will not hurt garlic.
Timing for fall planting is important. In south-central Illinois, a mid to late September timing is ideal while in far southern Illinois garlic can be planted through mid-October. Depending on local conditions, too early may lead to too much tender top growth by winter; too late and not enough root development occurs.
Soil requirements for garlic include high organic matter levels and good drainage. A waterlogged soil will cause cloves to rot. Prior to planting add about 1 to 2 pounds of a general analysis fertilizer (10-10-10) per 100 sq. ft., along with compost. Spade and till these amendments well into the soil. Form raised beds if your soil is heavy or poorly drained. Lay out planting rows 15 to 18 inches apart. Separate individual cloves from the main bulb and plant them about 4 to 6 inches apart in the row. The larger cloves of elephant garlic should be set 6 to 9 inches apart. As a general rule, the larger the clove, the larger the bulb will be at harvest. Cloves should be set with tip up, and 1 to 2 inches below the soil surface.
Because garlic is a poor competitor, good weed control is important. Though fall and winter weed problems are minor, spring and early summer weeds can be invasive and should be controlled. Mulch the soil with straw or other organic materials soon after planting. This will also help to alleviate winter soil frost heaving that can damage new roots. In heavy soils, remove the straw once top growth is evident in the spring, or excess moisture may rot bulbs. Only during drought-like conditions should garlic be watered. As bulbs approach maturity avoid any supplemental watering. One or two soluble fertilizer applications (i.e. Miracle Gro™), in early and mid-spring will help promote vigorous and uniform growth.
During the growing season, be aware that garlic is susceptible to the same disease and insect problems as onions, such as thrips, onion maggots and bulb rots. However garlic is relatively care free when given a well-drained site with good air circulation, fertilized, and kept on a good rotation with other vegetables.
As flower shoots (scapes) form in late spring, be sure to cut them off. If allowed to mature to seed, they can reduce bulb size. Young garlic scapes are considered a garden delicacy and can be chopped into fresh salads.
Harvest garlic before the tops completely die down, preferably with 4 to 6 green leaves still attached. Remove excess soil, but do not wash, and lay whole plants on screens or hang in small bunches to dry. Allow it to cure completely in a warm, well-ventilated room, but not in direct sunlight. Watch for rotting bulbs, remove these and increase air circulation if needed using a box fan. Curing will take about 4 to 6 weeks. After that, roots and tops can be trimmed, and outer dirty skins can be removed. Store cured garlic in a cool dry place. Remember all garlic varieties taste the same at harvest time, but after curing and a few weeks of storage time, individual variety flavors will come out.
A few good varieties which have performed well in University of Illinois trials include "Spanish Roja" and "Carpathian", (both rocambole or hardneck types). Others include "Inchelium Red" "Idaho Silverskin" and "Persian Star"; which are softneck types. There are many varieties of garlic, and the best sources of planting stock are mail-order and internet specialty seed companies and diverse garden centers.
For more information on vegetable crop growing, check out the University of Illinois website "Watch Your Garden Grow" at: http://www.urbanext.uiuc.edu/veggies/. In addition a useful University of Illinois Extension publication which covers garlic and herb growing is "Vegetable Gardening in the Midwest" Publication # 1331, by Voigt and Vandemark, which can be ordered through your local County Extension office.
Source: Anthony Bratsch, Extension Educator, Horticulture (Serving East-Central and Southeastern Illinois), firstname.lastname@example.org
Pull date: October 25, 2008