Garlic Companion Planting

Companion planting is a system of growing certain plants in close proximity to help each of them thrive. Although the method is not an exact science, experienced gardeners know that well-matched companion plants help each other resist pests and diseases while attracting beneficial insects. Garlic (Allium sativum), affectionately known as "the stinking rose," is the workhorse of the garden when it comes to companion planting.

Garlic is a frost-tolerant, bulbous vegetable and herb that usually is grown as an annual but is perennial in U.S. Department of Agriculture plant hardiness zones 3 through 8. It contains several sulfur compounds that reputedly prevent fungal diseases from attacking it, a benefit that extends to its nearby bedfellows. In addition, allicin, the same compound responsible for causing garlic breath in people, acts on the sensory receptors of predatory insects, literally throwing them off the scent as they search for plant hosts.

Organic gardeners traditionally pair roses (Rosa spp., USDA zones 3 through 11) with garlic to deter ants, aphids and thrips as well as black spot and powdery mildew. Garlic is also said to enhance the fragrance of roses.

Certain fruit trees, including peach (Prunus persica, USDA zones 5b through 8), are protected from borers when garlic is planted around their bases. Because tree borers also target cherry trees (Prunus avium, USDA zones 3 through 8) and apricot trees such as "Wilson Delicious" (Prunus armeniaca "Wilson Delicious", USDA zones 5 through 8)*), planting garlic around those trees may be helpful.

Planting garlic near lettuce (Lactuca sativa) and celery (Apium graveolens var. dulce) helps to protect those vegetables from aphids. Nearby garlic also improves the flavor of beets (Beta vulgaris subsp. vulgaris), cauliflower (Brassica oleracea var. botrytis) and other members of the cabbage family (Brassicaceae). Positioned between tomato plants (Solanum lycopersicum), garlic deters red spider mites.

Plant garlic in fall six to eight weeks before your location's first average annual hard frost; plant it in February or March if you live in a southern U.S. state. Garlic purchased from a farmer’s market or grocery store is fine to plant as long as its variety is suited to your climate.

A few days before planting, separate the cloves from the garlic bulbs, leaving the paperlike skins intact on the cloves. Garlic requires full sun and organically rich soil with good drainage Plant each clove with its pointed end facing upward and 2 inches deep; space the cloves 4 inches apart.

Figure out how close garlic needs to be to its companion plant by averaging the recommended spacing for each of those plants. If, for example, you want to plant garlic near vegetables that should be spaced 12 inches apart, then allow for 8 inches between garlic and the vegetable plants.