Parsnip

Parsnips ask for patience twice: once when they're germinating, and once when they're ready to eat. The germination wait — 14 to 21 days in cool soil, with seeds that lose viability rapidly — is the first trial. The flavor wait — leaving the roots in the ground through the first hard frosts so that cold converts the starches to sugars — is the second. Skip either and you'll wonder why anyone bothers. Honor both and you'll understand why parsnip growers become devoted.

Seed viability is the issue most first-year parsnip growers don't see coming. Parsnip seeds are viable for only about a year; two-year-old seed may germinate at rates below 20 percent, which can look like a total germination failure but is actually just old seed. Buy fresh seed each year, from a reputable supplier, and sow thickly — many growers sow 3 to 4 seeds per inch and then thin, accepting that not all will germinate. Sow 2 weeks before your last frost date, when soil is still cool but not frozen.

While you wait for germination, keep the soil surface consistently moist. The usual approach is to lay a board or a sheet of row cover over the seeded row to hold moisture and block hard rain that can crust the soil. Check every two to three days and remove the cover the moment you see the first cotyledons emerging — the seedlings need light immediately. Interplanting radish seeds in the same row is a useful technique: the radishes germinate in 5 to 7 days, mark the row, break the soil crust as they emerge, and are harvested before the parsnips need the space.

Thin to 3-inch spacing once seedlings are established. The roots need depth to develop well — loosen soil to at least 12 inches before sowing, or use a raised bed with deep, rock-free mix. Parsnips and carrots are in the same family and share many of the same pests and diseases, including carrot rust fly and Alternaria leaf blight. Avoid planting them in the same bed in consecutive years. Also avoid letting parsnip plants flower if any bolt — the sap from the leaves and stems causes phototoxic burns in bright sunlight, a reaction called phytophotodermatitis.

The reward for the long wait is a root that tastes like nothing else in the fall vegetable garden: sweet, earthy, faintly nutty, with a richness that intensifies after roasting. Leave roots in the ground through the first several hard frosts — sustained temperatures below 28°F drive the starch-to-sugar conversion that makes a parsnip worth eating. In zones 5 and colder, mulch the bed heavily in late fall to keep the ground workable, and you can dig through much of winter. In mild climates, refrigerating harvested roots for several weeks before eating can approximate the cold-sweetening effect.