The first garlic shoots peeked above ground this week, reminding me that I love garlic. I love to eat it, I love to grow it, and I love how green it makes my garden in the early spring. It turns out that my garden loves garlic, too.
Garlic repels more than vampires: aphids hate it. These tiny insects cause big problems for gardeners and commercial growers. Plants in the mustard family, including kale, broccoli, cabbage, and mustard, seem to be aphids’ food of choice. In a 2007 study of mustard plants (used for oil), fewer aphids were found on mustard plants grown between rows of garlic or onions than on pure mustard crops. Furthermore, mustard and garlic planted together produced more edible biomass than mustard grown with onions or alone.
Fungi, which can damage roots and kill seedlings, also hate garlic. Conventional treatment of fungal infections requires potentially toxic fungicides, but ‘intercropping’ with garlic may be another option. When garlic was grown with lentil plants in this 2012 experiment, the lentils showed less fungal damage and higher yields.
Garlic can even increase the amount of nutrients that plants get from the soil. Hoop houses containing garlic and cucumbers in this 2013 study grew bigger cucumbers that absorbed more nitrogen, potassium, and phosphorous than cucumbers grown without garlic. There was even a benefit to cucumbers grown 45 days after the garlic plants were removed from the soil, so rotating blocks of garlic in your garden each year may help the plants that follow the garlic.
Try growing garlic next to plants that suffer from aphid or fungal infestations, or include blocks of garlic in your crop rotation to improve soil quality without additives (for more information on crop rotation, see my post here). Grow lots of garlic: some ‘hardneck’ varieties will keep for almost a year, and you can replant a portion of your garlic cloves in the fall. We are still eating garlic harvested last year… but I may have to plant some cloves with my kale this spring to keep away the vampires (and aphids).
Buy garlic heads from a certified vendor and rotate where you grow it to avoid white rot. To plant, break apart the garlic heads and bury individual garlic cloves about six inches apart with the root-side down. Maximize your garlic yield by planting in October and mulching with a thick layer of straw during the winter, or plant garlic in the spring as a ‘companion plant’, interspersed among other plants to help repel pests organically. Expect smaller garlic heads with the second technique.
Harvest by digging up the bulbs when a few of the bottom leaves have turned brown but the top leaves are still green (usually in July or early August). Brush, don’t wash, the dirt off, and place in a warm, well-ventilated space for several weeks, tops and all. When the tops are completely brown, the plant is ‘cured’, and you can trim the roots and tops, leaving only a few inches of stem. Store in a cool, dark space.
Abdel-Monaim, M. F., & Abo-Elyousr, K. A. (2012). Effect of preceding and intercropping crops on suppression of lentil damping-off and root rot disease in New Valley–Egypt. Crop Protection, 32, 41-46.
Xiao, X., Cheng, Z., Meng, H., Liu, L., Li, H., & Dong, Y. (2013). Intercropping of green garlic (Allium sativum L.) induces nutrient concentration changes in the soil and plants in continuously cropped cucumber (Cucumis sativus L.) in a plastic tunnel. PloS one, 8(4), e62173.