How to Grow Garlic Indoors

Spicy, pungent garlic (Allium sativum) is among the simplest, most rewarding plants to grow at home. It needs specific conditions, such as chilling, to produce its characteristic bulbs, which makes it difficult to grow indoors. Indoor garlic rarely produces bulbs as large as those in grocery stores, but its green, grasslike sprouts can be used as a spicy, aromatic herb with a piquant, garlicky flavor.

Garlic comes in two varieties: softneck garlic (Allium sativum var. sativum) and hardneck garlic (Allium sativum var. ophioscorodon). Most grocery store garlic is softneck garlic, which is valued for its strong flavor and long storage life. Hardneck garlic tolerates cold better than softneck varieties and is noted for its milder flavor.

Both varieties perform equally well in pots, although softneck garlic needs less chilling and performs better indoors.

Bulb formation in garlic occurs after a brief chilling period, known as vernalization. Garlic needs six to eight weeks at temperatures below 40 degrees Fahrenheit for proper bulb development, and that time period should be followed by a rapid increase in warmth and light. To mimic natural vernalization, place garlic bulbs in a paper bag inside the crisper drawer of a refrigerator for six to eight weeks before planting them in pots. Chill and plant garlic in autumn for a harvest the following summer.

Garlic is typically grown as an annual plant, but it is technically a perennial in U.S. Department of Agriculture plant hardiness zones 4 through 9.

The right conditions mean the difference between a bountiful garlic harvest and failed, rotten bulbs. Soil, light, moisture and temperature all play a role in garlic plants' development, but, except for watering, they need no attention or care as they grow.

12-inch-diameter pot

Organic compost

Medium-grit sand

Tablespoon not used for food

5-10-10 or other Allium-formula fertilizer in granular form

Measuring cup not used for food

Tape measure

Watering device

Shop light (optional)

Fill most of a 12-inch-diameter pot with a soil mixture that is one-half organic compost and one-half medium-grit sand. Ensure the pot has several drainage holes in its base. Mix 1/3 tablespoon of granular, Allium-formula fertilizer with a low nitrogen-to-phosphorus and low nitrogen-to-potassium ratio, such as 5-10-10, for each 4 cups of the soil mixture. Fill the pot to within 1/2 inch of its top with the mixture. Water the soil mixture to settle it.

Break one garlic bulb into its individual cloves by hand. Plant the cloves 1 inch deep in the pot's soil mixture, leaving roughly 4 inches between cloves and at least 1 inch between each clove and the edge of the pot. Ensure each garlic clove’s pointy end points toward the soil surface and its blunt root end points to the bottom of the pot. Do not plant the cloves upside-down.

Position the pot within 1 foot of a non-shaded, south-facing window that receives at least six hours of sun exposure each day during winter months and roughly 13 hours of sunlight daily during summer months. If sufficient natural sunlight isn’t available, suspend a shop light 15 inches above the pot to lengthen daylight artificially. Adjust the light's position as the plants grow, keeping it at least 6 inches above the tips of the garlic foliage.

Water the garlic's soil mixture whenever it feels nearly dry beneath its surface. Add water until it trickles from the bottom of the pot. Avoid overwatering. Excess moisture encourages bacterial and fungal growth in garlic bulbs. Discontinue watering after the garlic plants' foliage starts to die back.

If the indoor temperature is below 70 degrees Fahrenheit during the summer months, then place the garlic's pot on a heat coil or propagation mat to warm the soil mixture.

Garlic greens, or leaves, make a serviceable replacement for chives (Allium schoenoprasum, USDA zones 4 through 8). The leaves can be harvested sparingly during the growing season as soon as they reach 8 to 10 inches in height. Remove no more than one-third of the greens by using sharp kitchen scissors that were wiped with rubbing alcohol. Rinse the harvested garlic greens with clean water, and use them as you would chives.

Garlic bulbs swell and grow rapidly during the summer months if they receive enough warmth and light. They are ready for harvest when one-half of their plant's foliage dies back and turns yellow. Dig up the bulbs rather than pulling them up by their foliage to harvest them. Brush soil off the bulbs, and spread them on a sheet pan in a warm, dry and airy location to cure for at least one week. Keep their location's temperature about 80 degrees Fahrenheit, and protect them from direct sun exposure while they cure. After the bulbs cure but before you store them, snip off the old foliage 1 inch above each bulb by using sharp, clean scissors, and clip off the long, scraggly roots. Also, remove the dirty outer skin from each bulb if desired. Store the garlic in a cool, dry place where temperatures stay 60 to 65 degrees Fahrenheit.

Cured garlic bulbs have a stronger flavor and longer shelf life than garlic bulbs that aren't cured. Cured bulbs can last three months or longer under the right conditions.

Garlic is toxic to dogs and cats. So keep the pot of garlic away from them.