How to Plant Garlic in Ontario
The following information will help you learn how to plant garlic in Ontario, including varieties, planting dates, planting depth, techniques and plant spacing.
There are literally hundreds of varieties of garlic available worldwide, but only some of them can be grown well in Ontario. Of those varieties, they can all be grouped into two types called hardneck and softneck.
Hardneck varieties bolt during late spring or early summer, producing a flower stalk called a scape. At the tip of the scape is a capsule containing bulbils (small aerial cloves) is produced instead of a true flower. You should remove these scapes to maximize the size of your bulbs at harvest.
Softneck varieties do not produce a scape, although they sometimes produce bulbils in the stock of the plant, especially in cold climates.
Purple Stripe variety (left) and a Porcelain variety (right)
The main hardneck family groups grown in Ontario include Marbled Purple Stripe, Rocambole, Porcelain, and Purple Stripe. These all do well in Ontario's climate and can grow large healthy bulbs.
The two Softneck family groups grown in Ontario include Silverskin and Artichoke, although the Artichoke family tends to do better because it is more suited to Northern climates.
When choosing garlic varieties to grow, you want to find ones that are cold hardy, develop large bulbs and have great flavour. Most Canadian garlic meets these criteria, however, the three most popular varieties that we grow on our farm are Music, Spanish Roja and Persian Star. They consistently do well and often outperform other lesser known varieties.
In Ontario, garlic is usually planted in the fall so that cloves are exposed to the cold temperatures (vernalization) that many types of garlic require. Garlic can be planted in spring, however, the plants often form single cloved bulbs (called rounds) and or they grow normal bulbs that are much smaller than the fall planted cloves (see our Planting Garlic in Spring article for more info).
The best fall planting date for garlic depends mostly on where you live in Ontario. Your goal is to plant early enough to have the cloves develop a large root system, while at the same time planting late enough that garlic clove don't sprout and show green top growth above the soil.
This means that the date for planting can range from the last week of September to as late as the end of November depending on where you live and how long you want your cloves to settle in before winter.
In colder zone 3 or 4 regions such as Northwestern Ontario where winter comes early, garlic can be planted as early as September 21 or as late as the end of October.
In warmer regions like southern Ontario, planting can range from early October until the last week of November.
If you plant your garlic early in the fall, you can sometimes end up with a small amount of green top growth above the soil line going into winter. These first green leaves may die back if they are exposed to very cold temperatures, however, the cloves will re-grow new leaves in spring.
A garlic clove that was planted early and emerged from the soil before winter.
Planting garlic in nice straight rows or in a uniform layout is also highly recommended. Garlic tends to require a lot of weeding, and straight rows makes this much easier. Using a string, long stick with markings or a dibbler to indicated perfect spacing helps significantly.
When possible, garlic cloves planted by hand should be pushed into the soil with clove tips pointed upward and their flat bottoms pointed down. This allows the first leaves to emerge from the ground easily in spring and ensures that the garlic necks do not grow crooked. This is more important with hardneck garlic varieties as upside down cloves often form smaller, odd shaped bulbs.
Another option used by larger garlic growers and some gardeners, is to plant cloves on their sides, which makes the process easier and saves time. A long furrow is dug the length of the planting area, cloves are laid on the bottom and the furrow is covered with soil burying the cloves.
When using this method, most of the garlic plants will develop normal shaped bulbs, however, some of them will sometimes be slightly misshapen. Softneck cloves tend to be affected the least by side planting and tend to turn themselves upright which allows the bulb to form normally.
A furrow being dug before planting garlic cloves on their sides.
Garlic cloves can be planted anywhere from 1 to 3 inches (2.5 to 7.5 cm) deep. Some growers plant deeper than 3 inches, however this only works well in very loose and fluffy soils that drain very well.
Generally any deeper than 3 inches is excessive and will force the garlic cloves to use valuable energy when emerging from the soil, limiting the size of the harvested bulbs due to the force of the soil pushing down on the bulbs while growing.
How deep you choose to plant your cloves will depend on two factors. First is the type of soil you have and how well it drains. In poorly draining soils like clay, or regions that generally receive high amounts of rain, planting deeper than 1 or 2 inches can cause the garlic to rot during cool temperatures or during wet periods. In sandy or very well drained soil, planting less than 2 or 3 inches can lead to drought stress during dry periods.
The second factor to consider is the climate of your region. The deeper a garlic clove is planted, the more winter protection it has. In the warmer regions of Ontario, where winter conditions are mild, depth is not really a concern. In very cold areas, planting on the deeper side can help protect the cloves over the winter.
Planting garlic cloves 1-inch deep in heavy clay soil.
Cloves can be planted anywhere from 4 to 8 inches (10 to 20 cm) within the row and 6 to 12 inches (15 to 30 cm) between rows, with wider spacing sometimes used to accommodate equipment.
How close or how far apart you decide to plant your garlic will depend on how you plan to weed around the plants, your space limitations, the type of garlic being grown and your goals regarding size and quality.
Space for Equipment
For growers using equipment such as tillers or tractors for tasks like weeding, the spacing of the garlic has to allow for movement of the equipment through the field or garden. Enough space must be given to ensure that tiller tines or tractor wheels don't hit the sensitive garlic plants or roots even when they are almost full grown. What looks like a lot of space when planting the cloves in fall, often seems too close once the garlic is growing during the summer, so using a wider spacing is a good idea.
Garlic planted in rows 12 inches apart between rows and 6 inches within the row.
Space for Small Areas
If you have a small growing area, have good soil and want as much garlic as possible, then planting your garlic with very close spacing is a good option. Some of the nicest looking garlic in Ontario is grown by market gardeners or homeowners that use very tight spacing.
The key to their success is supplying adequate moisture to the plants, consistent weed control and high soil fertility. If you have a large area or marginal soil conditions, then using a wider spacing is usually a better choice. This will reduce the competition between your garlic plants for water, light and nutrients as well as make your job of weeding much easier.
Space for Large Varieties
If you are growing a variety of garlic that tends to produce large bulbs and/or you are trying to grow the absolute largest garlic possible, then giving each plant a large amount of space is the best practice.
In general, individual garlic plants do not need a very large amount of space, however, using a plant spacing on the wider side will definitely improve your chances of growing large, healthy garlic that looks uniform.
Soils and Fertility
Garlic grows well on a wide range of soil types including both sand and clay. It can be cultivated anywhere in Ontario that can grow cool season vegetables.
High organic matter soils are ideal because of their high moisture and nutrient holding ability. These soils are also less prone to crusting, settling or compaction issues. Very heavy soil types can be a challenge and hard to work with, especially under wet conditions. Intensive soil management practices are required on light sandy soils due to their low moisture-holding capacity.
Garlic is a heavy feeder and grows very well on fertile soils. Poor fertility is one of the most common reasons growers end up with small bulbs. To help ensure optimal nutrient levels, it is best to apply a balanced Organic Fertilizer when possible. Fertilization can be split into three or four applications. Once in the fall and two or three times in spring.
If using conventional fertilizer, all the phosphorus and potassium should be added and incorporated before planting. About 1/3 of the nitrogen should be added just before or just after planting in the fall. The remaining nitrogen should be split into several applications starting first thing in spring and ending about one month before harvest.
Taking a soil test before planting garlic is recommended in order to verify nutrient levels. The following are general fertility recommendations for garlic in Ontario, however, they could be higher or lower depending on the soil type, length of growing season and previous crop grown.
Pounds per Acre
Pounds per 1000 ft2
120 lbs (55 kg)
3 lbs (1.3 kg)
160 lbs (73 kg)
4 lbs (1.8 kg)
150 lbs (68 kg)
4 lbs (1.8 kg)
30 lbs (14 kg)
1 lb (0.5 kg)
Fertility recommendations for growing garlic.
Most Ontario growers mulch their garlic for the winter. Mulching helps moderate soil temperatures and keeps the cloves protected from fluctuating temperatures.
It is important to ensure that mulch materials are not contaminated with garlic pests, such as nematodes, bulb mites, diseases, or weed seeds. Wheat straw is the most commonly used mulch and should be applied 4 to 6 inches (10 to 15 cm) deep directly over the planted garlic. Other types of mulch such as oat straw, barley straw or hay can also be used.
In early spring, some growers remove the mulch completely once the threat of extreme cold is gone. Removal helps warm the soil once the snow melts, minimize disease during wet weather, and make weeding easier during the growing season. Other growers leave it on for the whole season to help conserve moisture and provide a barrier for weed control.
See our Growing Garlic articles for even more information!
About the Author: John Côté owns and operates John Boy Farms with his family who have been farming the same land for over 140 years. As an agronomist and experienced farmer, he helps others learn how to grow garlic successfully. He has written many articles and is the author of The Master Guide to Growing Big Garlic.