Swiss Chard Growing Calendar: One Sowing, Half a Year of Picking

Two sowings cover the year

Unlike most leafy vegetables, chard does not need successional sowing. One spring sowing crops from early summer until the hard frosts, and one late summer sowing overwinters and crops from late winter into the following spring. Two sowings, and you have leaves available for most of the year.

The two sowings have quite different characters. The spring crop is fast, heavy and prone to bolting in its second season; the late summer crop grows slowly into the cold, sits through winter and then produces the sweetest leaves of the whole year before it runs to seed. Plan both if you have the space, and the late summer sowing first if you only have room for one.

Chard is a biennial. It grows leaf in its first year and flowers in its second, which is why an overwintered plant bolts in spring however well you treat it.

Spring: establishment

Spring is about getting plants established before the heat, and about the last useful picking from anything you overwintered. Do not rush the sowing; chard sown into cold wet soil germinates badly and is overtaken by a sowing made two weeks later.

Overwintered plants bolt in mid spring. Take everything usable off them in one go when the flower stem appears, then pull them and use the bed.

Summer: the productive months

Summer is when the spring sowing pays. Regrowth is at its fastest, at five to seven days between picks, and the main jobs are keeping up with picking, keeping the water on and preparing for the late summer sowing. Heat management matters more than anything else: dry roots and full afternoon sun are what turn chard bitter.

This is also the peak of leaf miner activity, so it is the season where the weekly habit of turning leaves over and stripping mined outer leaves pays for itself.

If leaves turn bitter in the heat, pick them younger and smaller rather than waiting for size. Quality returns as soon as the nights cool.

Autumn: the best quality of the year

Cool nights and shorter days produce the best chard you will eat. Growth slows so the intervals between picks stretch to ten days or a fortnight, but the leaves are tender, the midribs thick and the bitterness gone. The main decision of the season is which plants you are overwintering, because those need to stop being picked.

A plant carried into winter with a full head of leaves survives. One picked hard in late autumn usually does not, so make the decision in mid autumn and stick to it.

Winter: standing still

Chard is hardy to around 15F (minus 9C) and in most gardens stands through winter with only a row cover. It puts on almost no growth below 45F (7C), so what you have in early winter is broadly what you will have in late winter. Treat the bed as storage rather than as a crop.

The leaves flop and look finished after a hard freeze and then stand up again as they thaw. Do not pull plants on the strength of how they look the morning after a freeze; wait a few days and see what the crown does. As long as the center is firm and green the plant will come back.

Water almost never. Cold wet soil around a dormant crown is what kills overwintering chard, far more often than the cold itself, and this is doubly true of plants in containers.

Record the date growth restarts, the date the flower stem appears and the dates of your two sowings. Chard's calendar shifts by weeks between gardens, and after one year your own dates beat every general figure here.