I belatedly decided a few autumns ago that I really ought to find out the answer.
Briefly, that answer is yes. Over recent winters I’ve tried various combinations of containers, composts, and number of garlic cloves, and this is what I’ve found.
Autumn-planted garlic will produce a reasonable crop in almost any container, but I’ve consistently had my best results by using 10-litre plastic pots, with one clove of garlic planted in each. October and November are the best months for planting.
Any variety of autumn-planting garlic will do, though the one I’ve had most success with is the widely available Extra Early Wight, which is a fast-growing type, usually ready for harvest by late spring or early summer.
You could just use a leftover clove from garlic bought for eating, but then you’re taking a chance that what you’ve planted might not be a suitable cultivar for the time of year or for the British climate.
Spring-planted garlic is harder to grow in pots, simply because the compost is more likely to dry out frequently in the warmer months.
Fill your pots with any brand of peat-free multipurpose compost. I’ve often reused compost that had previously grown other crops, like potatoes, refreshed with a handful of organic fertiliser, but for maximum reliability you’re better off with a fresh supply.
Plant the cloves with the flat base at the bottom and the pointy end at the top, so that the tip is about one inch below the surface of the compost.
Preventing the pots getting waterlogged over winter is important, so they’re best placed on hard-standing, and raised off the ground slightly to allow for better drainage. You can buy special “pot feet” for this purpose, or just use whatever comes to hand, such as half bricks.
You won’t see much sign of the garlic at first, but in the new year the green tops will grow quite rapidly. The pots are unlikely to need watering at this time of year, so there isn’t much to do other than pulling out any weeds that appear.
Towards the end of winter, about late February where I live, it’s worthwhile, though not compulsory, to top-dress garlic with a sprinkling of organic potash pellets.
Harvest garlic when the green foliage starts to go limp and yellow. Gently lift the bulbs from the compost with a hand fork, taking care not to bruise them, which could lead to rotting in storage. Unless you’re planning to use it all straightaway, allow the garlic to dry off for two to four weeks, in a dry, well-ventilated place, warm but not hot.
As well as being useful for those without open ground to grow their garlic in, pot culture also helps if your soil is very wet over winter, or if you’ve had trouble with persistent diseases like white rot.