AS EARLY autumn harvests create gaps in the vegetable bed, it’s time to order onions, garlic, elephant garlic and shallots for planting in September and October.

All alliums that are grown through the winter need to go into open ground, where they won’t be overshadowed, to take advantage of the available light during the short days.

They must also be in soil that drains well, so that they’re not spending long periods sitting in puddles or saturated earth. Other than that, any ordinarily fertile soil will do.

Elephant garlic, with its jumbo-sized, subtle-flavoured cloves, isn’t true garlic but is raised in much the same way. It’s best planted from late September to mid-October, setting each clove 12 inches (30cm) apart each way, the narrow end uppermost, one-and-a-half inches (4cm) below ground. Keep your elephants weed-free and, in dry weather, well watered.

For ordinary garlic, make sure you’ve bought a variety that is recommended for autumn, rather than spring planting.

The cloves are planted in the same way as those of elephant garlic, except that, because they produce much smaller plants, the space between them can be reduced to about 7in (18cm). Late October into early November is the preferred time to put them in.

Overwintered onions are also known as sweet or sandwich onions, or Japanese onions, and still aren’t as widely grown in this country as they deserve to be.  They’re easier to grow than maincrop onions, and will be ready for eating by early-to-mid summer.

The best-known Japanese onion is Senshyu Yellow. In my experience it is still the most reliable and productive overwintered onion, and in my opinion it still has the best flavour.

You can start the onions either from seed, or from sets — which are small bulbs. Seed is cheaper; sets are easier.

Seed is sown in August or September, either in compost, in trays or cells, for planting out in October, or else directly into drills in the soil, half an inch (1.5cm) deep, in which case wait until next spring to thin them out so that they are 6in (15cm) apart.

Plant onion sets in October, putting them about 6in (15cm) apart each way, and mostly buried so that their tips are just showing above ground.

Shallots also come in autumn and spring planting types, so again you need to make sure you’ve got the right one. My favourite is Jermor, not least because its long, large bulbs are easy to peel.

They keep well, have a lovely flavour, and make excellent pickled onions. Plant the sets any time in autumn, about 6in (15cm) apart, tips just showing.     

All these autumn alliums can be started off in small pots of multi-purpose peat-free compost, in the event that the soil is too wet or frozen, or still too dry from summer, to be useable.

They are then planted out into their final positions either later in the autumn, or, if necessary, at the end of the winter.