Swiss chard.

Conditions at a glance

• Light Sun · copes with light shade
• Warmth Cool-season by preference, but stands summer heat
• Humidity Not fussy
• Water Steady — growth stalls and leaves toughen in a dry spell
• Pot size A container at least 40 cm wide and deep
• First harvest Baby leaves ~5 cm · full stalks once the plant is 20 cm tall

Grow it in your space

1. Sow about 2.5 cm deep and 10 cm apart, in rows 45 cm apart, from mid-spring through midsummer.
2. Don't rush it into cold ground. Chard will not bolt in summer, but a cold spell early on can convince it that winter has already happened — and then it flowers instead of feeding you.
3. Thin to 30 cm between plants for full-size stalks, or leave them 5 cm apart and treat the row as a baby-leaf patch.
4. In a container, give it at least 40 cm across and 40 cm deep — it makes a big plant, and a small pot is what makes the leaves small and tough.
5. Sow a second batch in midsummer. That one overwinters outdoors and picks up again first thing in spring, which is how you get leaves for most of the year from two sowings.
6. Keep the soil moist. There is no trick beyond that; chard's reputation for being unkillable is mostly earned.

How to tell it's ready

• Outer stalks first, always — cut them right at the base and leave several leaves in the middle. Those are next month's harvest; strip the plant bare and you wait weeks instead of days.
• Usable size beats a calendar date — take a leaf whenever it is big enough to be worth cooking. There is no point at which chard is officially ready.
• Baby leaves up to about 5 cm — small leaves are mild enough to eat raw in a salad; anything larger is better cooked, and the stalks want a few minutes' head start over the leaves.
• Or take the whole plant at 20 cm tall — cut everything about 5 cm above the base and it regrows from the stump. Useful when it has got away from you and gone leathery.

Watch-outs

• Beet leaf miner — pale winding tunnels or dry brown blisters inside the leaf. Squash the mine between finger and thumb or pick off the affected leaves — the plant carries on regardless, and the rest of the leaves are fine to eat.
• Slugs and snails — the main threat while it is small; a seedling can vanish overnight. Established plants shrug them off.
• Birds on seedlings — they pull up new seedlings before you have noticed them germinate. A net or some mesh for the first few weeks is enough.
• Bolting after winter — an overwintered plant flowers in its second spring — that is its life cycle finishing, not a mistake you made. Take a last cut and sow again.
• Downy mildew and grey mould — grey or fuzzy patches in damp, crowded conditions. Thin properly and give the plants room; both are far less likely with air moving between them.