Growing garlic

 

Robin Gale-Baker, from Sustainable Macleod, discusses growing broad beans. She has also written articles for this website about growing broad beans, cauliflower, eggplants and capsicums, other vegetables, apricot trees, blueberries, medlar trees, persimmon trees, other fruit trees and herbs. Also articles on growing techniques, mulch, shade cloth and the emergency kitchen garden.

Also, read Helen Simpson’s guide to growing garlic.

Additional material from Guy’s tips: is now really the right time to plant garlic?.

In a Sustainable Macleod newsletter Robin Gale-Baker ruminated about whether the recent warm weather means that we should be deferring our garlic planting. She and I have subsequently debated the subject in more detail. It is a tricky issue, with no clear answer. The salient facts are:

  1. In Melbourne, garlic is usually planted in April.
  2. Robin thinks that the soil is currently too warm for garlic planting.
  3. According to Gardenate, it is ok to leave the planting until May (or even June).
  4. Like onions, garlic plants are sensitive to the length of the day, with the start of bulb formation (and the end of leaf growth) being triggered by a day length exceeding X hours. (This website says that X=13 and this website says that this will happen on 13th October.)

If you plant too early (i.e. when it is too warm), a risk is apparently that the resulting bulbs don’t divide into separate cloves. If you plant too late, a risk is apparently smaller bulbs (because, per day length, the garlic starts trying to form bulbs when it is too young). One potential way around this dilemma is to keep the garlic in the fridge for 30-40 days before planting. I am going to try all the possible options and will report back in due course.

I decided to run a controlled experiment. Rows of garlic were planted two weeks apart over an 8-week period from mid April to mid June. In addition, some garlic was kept in the fridge for 40 days from mid April and then planted. All the plants died back at the same time (second half of November) and were harvested on 24th November. The key results were:

  1. The April plantings produced a normal number of normal-sized garlics with normal cloves.
  2. The May plantings produced the same results as the April plantings but in a bit less time.
  3. The non-refrigerated June plantings produced much smaller bulbs, half of which were not divided into cloves.
  4. The refrigerated June plantings (perhaps surprisingly) produced the same results as the April and May plantings.

The conclusion: continue to plant your garlic in April or May even if the weather is warm. If you forget, try putting your garlic into the fridge for a bit before planting.

Planting

[Editor’s note: Robin and I debated garlic planting a couple of years ago. If you plant garlic too early (i.e. when it is too warm), the resulting bulbs may not divide into separate cloves. If you plant too late, the bulbs may remain small (because, driven by length of day, the garlic starts trying to form bulbs when it is too young). One potential way around this dilemma is to keep the garlic in the fridge for some time before planting. I experimented with different timings and different refrigerations and one of the conclusions was that refrigeration did, indeed, allow for later successful plantings. Read the results of the experiment.]

In the ‘old days’, before climate change, garlic would often be planted in March but these days the ground is too warm then (the perfect time to plant garlic is when soil temperature is 10°C at a depth of 8cm at 9am in the morning). Arguably, this is also becoming the case in April. So, commercial growers are increasingly giving their garlic a ‘false winter’ by refrigerating it for 40 days and then planting it out in May. This process is called vernalisation and helps late-planted garlic to develop large bulbs. If you want to copy these growers, you should be purchasing your garlic soon and refrigerating (not freezing) it in mid- to late-March. Buy from reputable sources (probably online or at farmers’ markets as nurseries won’t yet be stocking garlic heads) and do not use imported garlic as this may well have been sprayed with methyl bromide and a shoot inhibitor.

When preparing your garlic, select healthy heads, do not separate the cloves (as this could result in infection when removed from the basal plate), place in an airtight container in the fridge and remove 40 days later in May. Plant the large outer cloves at a depth of 2cm (i.e. the tip has 2 cm of soil above it) at 15cm intervals in rows 15cm apart, and apply a thick layer of loose mulch.

Garlic requires regular watering and, with drier winters, this needs to be done by hand, dripline or in wicking beds. In November or early December the plants will be ready to pull. Water up until 2 weeks before harvest. Ceasing watering then will allow the garlic to dry out, but also check the likely rainfall when planning when to harvest and adjust accordingly.

There are many varieties of garlic. They are broadly divided into soft-necks and hard-necks, with the soft-necks having a stronger flavour. Different varieties can have very different shelf lives.

Harvesting

Garlic will typically be ready to harvest late November – mid December but you need two dry weeks so that the bulbs are not damp when pulled. If they are, dry them in front of a blow heater. Don’t knock the bulbs together to remove soil as this bruises them and they deteriorate quickly.

Garlic is ready for harvest when the bottom 4 leaves have withered and there are 4-6 green leaves remaining. This is roughly half brown, half green. The green leaves extend down into the bulb forming the skins. The more ‘skins’ you have, the longer the shelf life. Note that, as the lower leaves wither, they can be hard to see as they shrivel to almost nothing which can lead to harvesting too late in the mistaken belief that this process has not begun.

  2 Responses to “Growing garlic”

  1. Hi Robin,

    Thank you for the tip about refrigerating the garlic to grow larger bulbs. This article doesn’t mention soil preparation prior to planting out? Do you have some information on this?

    Many thanks

    Louise

    • The soil should be well-worked to a fine tilth – remove clods, sticks stones etc and dig and rake until it is fine particles. It needs to drain well too. Add a moderate amount of compost. As the plants grow, keep it well weeded and mulched – sugar cane is preferred – and keep it away from the stem to prevent collar rot. Robin

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