Planting Garlic – How Late is Too Late?

Robert Pavlis

I hear about a lot of people planting garlic in winter or even early spring. In most cases they never report how well the crop turned out so I wondered, how good is the crop if you plant late? Can you plant in spring, in a cold climate, and still get a good crop?

Planting Garlic - How Late is Too Late, by Robert Pavlis
Planting Garlic – How Late is Too Late, by Robert Pavlis

Best Time to Plant Garlic

Garlic can be planted most of the year in warmer climates, but in cool climates the traditional planting time is October (zone 5).

Garlic after being in the ground for 1 month showing significant root growth, planted Oct 1 in zone 5, by Robert Pavlis
Garlic after being in the ground for 1 month showing significant root growth, planted Oct 1 in zone 5, by Robert Pavlis

In a previous report I looked at the results of planting earlier than this date, and those results can be found in Planting Garlic – When is the Right Time.

One reason for planting earlier is that it gives the cloves time to set down roots in the warm fall soil. The picture to the right shows how much root growth takes place in one month after an October 1 planting. In theory, more roots in fall equals bigger bulbs in summer.

Soil Science for Gardeners book by Robert Pavlis

Garlic planted in December or early spring will be sitting in cold soil and will not make as large a root system. Then in spring when things warm up, such plants will be behind other garlic that was planted in mid fall.

Testing Garlic Planting Dates

I have grown garlic in the same bed for a number of years and they always produce a great crop with very large cloves. I am in zone 5 and grow hardneck garlic. I know from past experience that the whole bed produces about the same size garlic.

In fall of 2017 and spring 2018, I made four different plantings around the first of October, November, December and March. The ground was too frozen in January and February to plant anything.

Planting depth and spacing (4-5″) were the same for all bulbs. The bed was mulched with 3″ of wood chips after planting. Urea fertilizer was added the following spring. The beds were watered as needed to keep the soil moist. I find that the combination of clay soil, rain and mulch are enough to keep the soil moist most of the time.

Garlic Growth in Spring and Summer

The October and November plantings looked similar with respect to plant height and thickness of leaves. The December plants were clearly smaller in size and the March ones were even smaller. The March planting also had fewer leaves per plant.

Plant Size at Harvest Time

The picture below shows the size at harvest time. From left to right, early October, November, December and March.

The bulb size matched the top green growth, which is not surprising. October had the largest bulbs, closely followed by November. The bulbs from a December planting were significantly smaller and the March were even smaller. The largest of the March cloves were about the same size as the smallest October cloves and are considered to be too small for seed garlic. They will grow as seed garlic, but they would not produce large bulbs.

Garlic planted early October, November, December and March (left to right), by Robert Pavlis
Garlic planted early October, November, December and March (left to right), by Robert Pavlis

Should You Plant in Winter or Spring?

The results clearly show that earlier plantings will produce larger cloves, and a larger crop.

What is a surprise to me is that a March planting produced anything at all. I expected much smaller cloves from such a planting.

If you can, it is best to plant in October for zone 5. However, early December plantings will still produce a decent crop. Consider a spring planting only as a last reserve. It won’t produce much of a crop, but it is better than no crop. The other benefit of planting in spring is that it allows you to preserve the bulbs for a future planting. If, instead of planting in spring you had tried to hold the bulbs over until the next fall, they would have dried up and been useless. At least a spring planting gives you seed bulbs to plant in fall.

Garlic as a Companion Plant

Garlic is one of the most popular companion plants. It can be grown next to most plants as a natural pest and fungus deterrent. It takes up little space, is not fussy about soil and can grow in most conditions.

But does it actually work as a companion plant? Garlic – the King of Companion Planting

Growing Garlic

YouTube video

If the above does not play automatically, try this link: https://youtu.be/NuCqoGZEcks

Garlic Nematodes

If you grow garlic, take the time to understand this pest. It can destroy your crop.

YouTube video

If the above does not play automatically, try this link: https://youtu.be/hJdJV95WEMU

 

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Robert Pavlis

I have been gardening my whole life and have a science background. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

31 thoughts on “Planting Garlic – How Late is Too Late?”

  1. Hi, thanks for this helpful post! I’m planning to plant garlic in a pot and missed the optimal October window. Do you think it’d be successful to simply keep the pot inside for a few weeks to establish the early root growth, and then transfer it outside for overwintering? Thanks!

    Reply
  2. I have read all of your posts regarding garlic. (Hardneck/softneck, when to plant, companion garlic, etc)
    I am in zone 5, USA midwest Illinois, I think I heard you say once that our, zone 5 growing zone is the same as yours in Canada. (-20° winters?) I have around 160 days frost free growing season (early May- early/mid Oct.)
    Last year I planted both hardneck and softneck at the same time, same everything.(depth, soil, moisture, etc. A few varieties of each kind. The hardneck (music specifically) did the best. All of the other varieties produced small heads/small cloves. You asked in a different post about “why planting hardneck/softneck in northern climates.” I was thinking of planting softneck cloves in very early spring (March-when I can work the ground on south side) as an experiment. It seems that you don’t even mess with softneck varieties but do u think it would work? I want the sustainability of both kinds.

    Reply
    • As far as I know both types grow the same way, but different cultivars will grow differently. I don’t see why softneck would do better with spring planting.

      Reply
  3. For people like me who live in the Southern Hemisphere, would you mind mentioning, please, ‘early autumn’, ‘mid-winter’ etc rather than ‘October’, ‘January’ etc.
    Thank you. And thanks for all the excellent content!

    Reply
  4. i would like to have a phone conversation with you about an experiment i want to try in south carolina
    i want to build a double lined green house appr 50×500
    but,the bed will have glycol lines to simulate winter in july, and tricking the garlic that a frost is upon us stimulating growth. what do you think? email me for phone number

    Reply

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