Swiss Chard

Spinach bolts in heat. Lettuce bolts in heat. Swiss chard just keeps growing. This is the trait that earns it a place in gardens where other greens give up in June — it tolerates temperatures into the 90s without sending up a flower stalk, and it can be harvested continuously from late spring through the first hard freeze. For a gardener who wants fresh greens available across the whole warm season, chard is difficult to replace.

Direct sow three weeks before your last frost. Each seed is actually a cluster of seeds in a corky hull, so even if you plant one, multiple seedlings often emerge. Thin to one plant per twelve inches once they're a few inches tall. Crowded chard produces smaller leaves and airflow is reduced, which increases disease pressure. The seeds germinate in about a week in cool soil and faster as the soil warms. In hot climates, a second sowing in late summer can refresh the planting for a fall harvest when the older plants become ragged.

Chard is a reliable cut-and-come-again crop. Remove individual outer stalks by grasping each one at the base and snapping it off or cutting it cleanly. Leave the center rosette intact — at least four to six inner leaves — and new growth will continue from the center for months. Do not strip the plant to its center, or it will stall and may not recover. Each harvest encourages new growth; plants that aren't harvested regularly tend to put more energy into the central growing point than into producing harvestable outer leaves.

The biggest thing that goes wrong with Swiss chard is leaf miners — the larvae of a small fly that tunnel between the upper and lower surfaces of the leaf, leaving pale, winding trails or large papery blotches. They don't kill the plant, but they render affected leaves inedible. There is no spray that reaches the larvae inside the leaf — once you see the trails, remove and dispose of the affected leaves. Row cover from planting prevents the adult flies from laying eggs. In areas with heavy leaf miner pressure, row cover is practically mandatory for a usable crop.

Harvest chard in the morning when the leaves are crisp. Younger, smaller leaves — six to ten inches — are milder and more tender, good for raw use or quick sautéing. Larger, older leaves are better for braising, soups, and long cooking. The colorful-stemmed varieties like Bright Lights and Rainbow are the same plant as the solid-stemmed types in terms of flavor and performance, and they look striking in both the garden and the kitchen. In zones 7 and warmer, chard often overwinters and starts producing again in early spring before being replaced by a new planting.