When to harvest Garlic July 06, 2015 03:08

Many new gardeners and growers will often ask the question "when is the best time to harvest my garlic?" or "how do I know my garlic is ready to harvest?". There is some debate among garlic growers as to the perfect time for harvesting, but there are a few important guidelines to consider:

Time of Year

In Canada, garlic is usually harvested from mid-July to late-August depending on the region and type of garlic being grown. Although calendar dates can help determine when to harvest garlic in a certain location, they should only be used as a guideline. Garlic maturity and harvest times can be heavily dependant on weather conditions. Spring emergence, summer temperatures and moisture conditions all have an affect on when the garlic plants mature and when they will be ready for harvest. This means that garlic harvesting dates can shift from year to year in any particular growing area.  

Garlic Varieties

It is not a surprise that different garlic varieties are ready to harvest at different times. This can make things tricky if you have a number of different types of garlic in your garden or field. Although knowing the type of garlic you are growing will not give you a specific time when to harvest, it can help you to be prepared for when to start observing the plants.  

Generally, Asiatic and Turban garlic varieties will be harvested on the early side. They tend to mature very quickly and need to be harvested before they lose too many bulb rappers and split open. Other garlic varieties belonging to the Porcelain, Rocambole and Artichoke families take longer to mature and can be left in the ground longer.

Scapes

In hardneck varieties, scapes are formed during the growing season and removed before they fully form (see scape removal for more information). The garlic bulbs are usually ready 2 to 4 weeks after the scapes have emerged. This is not the main signal for when to harvest the garlic, but gives you an idea of when to start paying closer attention.

Garlic Leaves & Bulb Wrappers

The most reliable signal of when to harvest your garlic, is to observe the number of garlic leaves that have died versus the number that are still green. Garlic will continue to grow and increase its bulb size as long as there are still green leaves on the plant. This means that you want to leave the garlic in the ground growing for as long as possible to maximize bulb growth, but not so long that they start to deteriorate.

For Hardneck garlic, it is usually recommended that the bulbs are dug up when half the garlic plant leaves are still green and half are brown. Some growers like to harvest when there are still 1/3 of the leaves green and others when there are still 2/3 of the leaves green. This comes down to personal preference and depends on a few factors such as how much cleaning the garlic will require, how long you want the garlic bulbs to store once harvested and the garlic variety being grown.

It is important to remember that the number of leaves on a garlic plant corresponds to the number of bulb wrapper layers. This means that as the leaves turn brown and die, the corresponding bulb wrappers begin to die and deteriorate as well. For example, if you have 6 green leaves when a plant is harvested you should have 6 layers of bulb wrappers protecting the cloves and allowing for cleaning and handling of the garlic. If you have no green leaves, you probably have bulbs with exposed cloves that are unprotected. 

Softneck garlic varieties can usually tolerate a longer period of time in the ground leading up to harvest. They tend to have tighter, more durable wrappers that can usually handle a little more stress. Some growers wait until half the garlic plants have fallen over as the signal that harvest should begin. Although this works in some cases, it is still a good idea to follow a similar strategy described for hardneck garlic, as they share the same principles around the number of leaves and bulb wrappers.