Garlic is used in so many dishes, and with over 600 subvarieties, there is ample room for gourmet garlic growers to carve out a niche. For the home grower, a year's supply of garlic is easy to grow - and you can give away braids of it for presents throughout the year if you grow too much.
Garlic varieties fall into one of two basic categories: hardneck and softneck. Softneck varieties are best for warm climates, while hardneck is the garlic of choice for northern garlic farmers.
Softneck garlic stores and travels better than hardneck garlic. It also has a stronger flavor and generally speaking, larger cloves.
Description and Varieties of Garlic
You can plant garlic in the fall or the spring. Timing depends on your climate: in the north, plant garlic in the fall. In warmer climates, it is best to plant garlic in early spring (but seed garlic must be chilled first to break it out of its dormant state).
Plant cloves 2 inches deep if you plan to mulch (see Growing Notes below), 3-4 inches deep if you do not plan to mulch. Be sure to plant each clove with the pointy tip facing up and the basal/root end facing down.
Space cloves 4 to 6 inches apart in each row and 18 to 24 inches between rows for large bulbs. You can plant garlic more closely, but although you will grow more cloves, each clove will be smaller. However, many growers feel that close spacing increases total overall yield (in pounds of garlic per square foot of garden).
Garlic prefers loose loamy soil with plenty of organic matter. Separate bulbs into cloves right before planting, leaving the papery layer around each clove. Choose larger cloves for planting (use the little ones for eating or preserving).
Mulching your garlic can be very helpful. Mulch can protect against winterkill in cold climates.
It helps moderate soil temperatures, keeps weeds in check, and conserves soil moisture. Mulching is not recommended in wetter climates. Mulch for garlic can be straw, hay, swamp grass, reeds, chopped leaves or plastic.
Hardneck garlic produces a curly green flower stalk called a scape. Garlic scapes should be harvested from the plant as it grows so that the garlic concentrates its energy into growing the bulb larger. However, if you are growing bulbils for seed, allow the garlic scape to grow. Scapes are edible and delicious.
Pests and Problems
Garlic does not like freezing and thawing cycles, and mulching as described above can help this. Frost heaves can tear the roots off of the young cloves. Garlic isn't fond of summer heat either; again, mulch is a help here.
Be sure you obtain cloves from certified disease-free stock, because once a field has been infected with white rot fungus, it may take decades for the infection to completely clear. And nematodes can breed in garlic for up to six seasons before suddenly taking an entire crop. Besides using clean stock, inspecting plants and pulling any that look diseased, and using sticky traps for onion thrips, are the best management practices.
White rot, or Sclerotium cepivorum, is the most serious disease of garlic. White rot is a fungus that can strike all Allium crops, including onions. White rot-infected garlic plants can be identified because their leaves will turn yellow and the plants will die back partially and wilt. The roots rot as well, so infected plants may uproot easily. White rot typically develops from the middle of the season to harvest.
Nematodes, Ditylenchus dipsaci, are another problematic garlic pest. These microscopic animals are similar to worms and live inside the garlic plant itself, eating it as it reproduces. Nematodes do not need water to survive and they can live in the surrounding soil for several years. Nematode infestation can build up for several seasons without much damage, then strike and take out an entire crop.
Onion thrips are the most common insect that plagues garlic. Thrips damage the leaves when the rasp them to drink the sap of the plant, which slows the growth of the bulb. If severe, thrips may cause the garlic to wilt and die.
Soil should be evenly moist, with a dry spell two to three weeks before harvest time. If conditions are too wet near harvest, mold may grow.
Weeds are a big threat to garlic, so be sure to keep the plot well-weeded. Weeds can easily outcompete young garlic plants. Good mulch keeps weeds in check.
Water garlic evenly during early growth, but avoid watering for the last few weeks.
It's time to harvest your garlic when half to three-quarters of the bottom leaves have died. This usually happens by mid- to late summer - July and August for most areas.
Harvest a test bulb or two to determine maturity. Garlic should be well-wrapped but not split. To harvest garlic, loosen the soil with a shovel or fork and pull up plants by hand. Use caution because garlic bruises easily. If you are raising bulbils to propagate new garlic, harvest them now and dry them separately from the bulbs.
Storage and Preservation
You can eat garlic fresh out of the ground. But if you want to store it for winter, you must cure it first.
Place garlic in a dark place with good air circulation for two to three weeks after harvest to allow it to cure. For storage, you can braid softneck garlic. Trim stems of hardneck garlic to one inch above the bulb. Store it where it will have good air circulation, 65-70% humidity, and a temperature of 35 to 50 degrees Fahrenheit.
In warm sunny climates, garlic can be left in the field to dry, but it should be covered with leaves to prevent sunburn.
Cured garlic will keep at least six months and up to a year when stored in optimal conditions.
Garlic is propagated by planting cloves or using bulbils. Save 15 to 20 percent of your crop - making sure to use only truly disease-free bulbs! - for planting next season.
Propagating garlic using bulbils can be much more effective than planting cloves.
There are many more bulbils than cloves, making it easier to build up your planting stock. And since bulbils don't touch the ground, you have a lower incidence of soil-borne diseases. Plant them just like you would plant cloves.