Garlic is a hardy bulb that is normally planted in the fall. Photo: gardening.usask.ca
Garlic (Allium sativum) is not your usual vegetable: it’s truly in a class of its own. Just the fact that it should be planted in the fall* rather than the spring makes it quite unique. Imagine, a vegetable you plant just as you’re winding your vegetable garden down for the season!
*This article concerns growing garlic in a temperate climate, that is, in areas where there is a true winter with at least some snow. In mild climates, different types of garlic are planted and usually in winter or in very earliest spring rather than the fall.
Also, you can’t “sow” garlic as you would most other vegetables, at least not in the classic sense, because it doesn’t produce seeds. If you hear the term “seed garlic,” it refers to garlic cloves used for planting. (More on that below.)
During its domestication some 5,000 years ago, probably in Central Asia, garlic lost the ability to produce fertile flowers. Hardneck garlic does produce a flower stalk called a scape (or at least it will if you don’t harvest it for cooking purposes: read Garlic Scapes, the Forgotten Vegetable for more on that subject), but no flowers form. Rather, the flower head fills with small bulbs called bulbils.
Can you sow these bulbils? Sure, but be aware that they will not produce a mature garlic clove for 2 or 3 years. You can find more information on that in the article Can You Grow Garlic from Bulbils?
What Is It We Buy?
When you buy garlic for planting, available in garden centers from late summer through fall, you’ll find it looks exactly like the same garlic bulbs you find in the supermarket: a fairly large bulb covered with a papery “tunic” that can be white, purple or white streaked purple. Don’t plant the whole bulb! You need to tear open the tunic and extract the cloves (divisions of the bulb) inside. It is these cloves—and there can be 10 or more per bulb—that you’ll be planting.
💡Helpful Hint: Can you “skip a step” and sow garlic from the supermarket? Probably not. First, mass-produced garlic is often treated with heat or radiation so it won’t sprout and thus can be stored for ages. But what a disappointment when you sow cloves from supermarket garlic in the fall and nothing comes up in the spring! Also, supermarket garlic is usually imported from China and it is a softneck garlic (Allium sativum sativum), a variety best suited to mild climates, not cold ones. Farmer’s market garlic, though, is both locally grown (and thus the “right kind”), has not been “nuked” and can be a good source of seed garlic.
For most areas with cold winters, hardneck garlic (A. sativum ophioscordum), much hardier, is the best choice. There are several hardneck garlic cultivars suitable for cold climates, up to hardiness zone 3—‘Purple Stripe’, ‘Rocambole’, etc.—, but the most popular garlic in most areas with harsh winters is ‘Music’.
💡Helpful Hint: Your garden center usually only sells garlic that is suitable for your climate. That’s also the case with mail-order catalogs located in a climate similar to yours. With garlic, which reacts very differently depending on climatic conditions, it’s always best to buy locally.
Time to Plant
Plant garlic in the fall, usually from late August to mid-October, as it normally needs to undergo 4 to 6 weeks of cool moist weather before the ground freezes for the winter. Usually, garlic is planted after a first frost kills the other vegetables, thus freeing up space in the vegetable garden, but waiting until after frost hits is only a tradition, not an obligation. If you have empty space in your vegetable garden, you can plant the garlic much earlier, even immediately after harvest.
It is always wise carry out a crop rotation, only planting garlic in a location where garlic or any other allium (onion, chives, leek, etc.) has not been grown for at least 4 years. This helps to avoid diseases and some insects.
Prepare the soil by weeding and incorporating compost or slow-release organic fertilizer. Avoid fertilizers that are high in nitrogen.
Break up the garlic bulb into cloves and plant them in a sunny spot in well-drained soil, with the “pointy end” facing up. Plant at a depth of about 3 inches (8 cm), setting the cloves 5 to 6 inches (12 to 15 cm) apart. Cover with soil, then water well.
💡 Helpful Hint: In cold climates, always grow garlic in the garden, not in a container. It’s poorly suited to growing in pots outdoors, where the soil can freeze solid, killing the bulb.
After planting, it is always wise to cover the spot with 3 to 4 inches (8 to 10 cm) of mulch. Farmers often use straw as mulch, but fall leaves shredded under the mower are the mulch of choice in most home gardens, since they’re free and readily available in the fall.
Garlic cloves depend on temperature to tell them when to start growing. As long as the soil remains warm, nothing will happen, but when the soil temperature drops below 50 °F (10 °C), they start to sprout. However, their growth likely will be imperceptible… because it takes place underground. As with tulip bulbs, they produce a sturdy root system in the fall. Leaves will follow in spring.
Sometimes, if the fall is very mild, a few leaves start to sprout early, usually in late November. This is actually the norm in regions with a mild climate, like California, but it’s a little less common in cold ones. If it does happen, don’t worry. After the ground freezes (and thus puts an end to their premature growth), try covering the leaves with mulch as extra protection. Even if they do freeze over the winter, the plant will produce more in the spring.
In spring, narrow, erect, ribbonlike leaves emerge from the ground. Garlic could almost be mistaken for some sort of weedy grass, but gives off a garlicky scent so you’ll know what it really is.
Spring and summer maintenance mostly involve watering as needed and weeding, as garlic doesn’t tolerate much competition, but if you’ve used a thick mulch, there won’t be many weeds to pull out.
If you’ve had trouble with leek moth, an insect that seriously damages garlic leaves (and also those of onions, leeks and other alliums) and even eats holes in the bulb, often leading to rot, it may be wise to cover your plantings with a floating row cover in the spring to keep the pest from reaching the leaves. You’ll find more on the leek moth here.
In the middle of summer, hardneck garlic will produce a scape (stem). (Softneck garlic won’t.) It grows upward at first, then forms a spiral, then a second spiral before finally straightening out. (Why does it do that? No one knows!)
If you’re into garlic scapes as food, harvest at the one and a half loop stage or it will tend to become woody. Even if you don’t want to use garlic scapes in the kitchen, you should snip them off (leaving the leaves intact, however). That will direct the plant’s energy to forming a bigger bulb with larger cloves.
As for harvesting, at least garlic tells us very clearly when to proceed. When the leaves start turn yellow and dry out, usually in mid to late summer, garlic bulbs will stop growing in size and are therefore ready for harvesting. Many gardeners harvest when half to two-thirds of the leaves are brown.
Do note that if you grow more than one variety of garlic, each will have a somewhat different harvesting window. How different will depend on the variety and your climate.
If you want bulbs for storage, dry the bulbs for a few days in a warm and ventilated place, then keep them at room temperature in fairly dry air for the fall and winter.
You don’t need to buy fresh garlic cloves each fall. Once you’ve started growing garlic, you can use the previous crop to start the next one. So, at replanting time, pull apart one of your larger bulbs. Of the cloves you find inside, keep the smaller ones for cooking. It’s the bigger cloves you’ll want to plant to ensure a bountiful harvest for the following year!
What About Spring Planting?
You’ll notice that the same garden centers that sell seed garlic in the fall also sell it in spring. Read Spring is Not the Season for Planting Garlic to understand why that is rarely a good idea.
Enjoy growing your own garlic!