Robin Gale-Baker, from Sustainable Macleod, discusses growing garlic. She has also written articles for this website about growing broad beans, cauliflower, celeriac, eggplants and capsicums, kohlrabi, tomatoes, other vegetables, herbs, how much sun do veggies need and the emergency kitchen garden. Also a number of articles about growing fruit trees and general growing techniques.
Also, read Helen Simpson’s guide to growing garlic.
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.
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.