Maincrop

When seed catalogues split a crop into "earlies" and "maincrop", they're really talking about how long it takes to mature and what you want from it. A maincrop variety sits in the ground for longer, gives a bigger harvest, and is bred to store. An early gives you a quick, smaller crop you eat fresh. Most beginners grow both, and potatoes are the classic example.

Maincrop vs earlies for potatoes

Potatoes come in four loose groups: first earlies, second earlies, early maincrop and maincrop. The earlies are fast — first earlies are ready roughly 10 weeks after planting, so you're eating new potatoes in June and July. Maincrop varieties need around 18 to 22 weeks, which is why they're lifted in September and October once the foliage has died back.

In the UK, you'd typically plant maincrop seed potatoes in mid to late April, a couple of weeks after your first earlies. Many growers chit them first — standing the tubers in a light, cool spot to sprout short, sturdy shoots before planting, though this matters less for maincrop than for earlies.

The trade-off is space and time against yield and storage. Earlies are out of the ground before the worst of blight arrives and free up the bed for a second sowing. Maincrop occupies the bed all season but rewards you with the heavy sacks of "old" potatoes — Maris Piper, King Edward, Desiree — that you keep for roasting, chipping and mashing through the winter.

Maincrop carrots (and other crops)

The same idea applies to carrots. Early carrot varieties like Nantes are sown from spring for tender summer pulling, while maincrop types such as Autumn King are sown a little later, grow larger and store better. Left in the ground or lifted into boxes of sand or dry compost, maincrop carrots see you through to spring. The term also crops up for onions, beetroot and peas, always meaning the slower, heavier, more storable option.

Storing the harvest

The whole point of maincrop is winter food. Lift potatoes on a dry day, let the skins dry for a few hours, then store unwashed in paper or hessian sacks somewhere cool, dark and frost-free — a shed or garage is ideal. Check them every few weeks and pull out any that have gone soft. Stored well, a good maincrop will keep your kitchen supplied long after the growing season has ended.

For the full sowing and lifting routine, see our guide to growing potatoes.