Endive

Endive is a plant that most American gardeners misunderstand from the start. It is not meant to be mild. The bitterness is the point — a sharp, mineral edge that cuts through fat and sweetness in a composed salad. But that bitterness can cross from bracing to unpleasant if the plant is grown in hot weather or left unblanched. Most home gardeners who try endive once and abandon it never learned that the timing and the final step matter more than the variety they chose.

The key to sweetness is cool weather. Endive sown in spring tends to bolt quickly once temperatures rise, and the leaves that form in heat are harsh and tough. The better crop is almost always the fall one — seeds sown in midsummer, maturing in the cooling weeks of September and October. Ten weeks before your last expected fall frost is a reasonable target, though in mild climates you can sow as late as August and still harvest through winter.

Blanching is the other half of the equation. About two weeks before harvest, when the heads are full-sized, gather the outer leaves up and tie them loosely with twine or a rubber band. This excludes light from the pale inner leaves, which sweetens them and makes them tender. If you skip this step, the heart will be as bitter as the outer leaves, and you'll wonder why you bothered. A week to ten days of blanching is usually enough; longer than that and the inner leaves may start to rot, especially if the weather is damp.

Endive can tolerate light frosts — in fact, a touch of cold often improves the flavor. But a hard freeze will collapse the leaves into mush. If frost is forecast and your plants are still in the ground, harvest everything or cover them with a floating row cover. The outer leaves can be composted or fed to chickens; it's the blanched heart that you're after.

The most common failure mode is bolting. If an endive plant experiences a sudden cold snap while still small — temperatures below 45 degrees for more than a few days — it may decide that winter has come and gone, and send up a flower stalk. Once bolting starts, the leaves turn bitter and the plant is done. Sowing at the right time, when the weather will stay consistently cool but not cold, tends to prevent this. In spring plantings, this means sowing early enough that the plant can mature before sustained heat; in fall plantings, it means sowing late enough that the seedlings don't experience a false winter.