When To Sow: February-March (under protection); April-June (direct seed) Harvest: August-November (or as needed after the first frost)
Germination: 8-21 days Full Sun
Parsnips prefer light, free-draining soil, free of stones and dug down to at least a foot in depth. Like carrots and other plants with long taproots, parsnips are best seeded in place and don't respond well to transplanting.
They need a long growing season, so start as early in the year as possible, ideally under a cloche or other protection. Avoid cold, wet soil.
Direct Seed: Sow fairly thickly at a depth of 12mm (½”) in rows 25 to 30cm (10 to 12”) apart. Alternatively, sow 3-4 seeds at 10cm (4”). Keep the soil moist throughout germination and be patient—parsnip seeds are not always easy to germinate. Soaking the seeds overnight may help to hasten germination. Thin out the weaker seedlings and leave the stronger plants 10cm (4”) apart.
Mulch after planting to help keep the soil cool and moist. Water regularly.
Planting tip: Sowing radishes along with the parsnips will help mark the row and keep the crust from hardening, making life a little easier for the parsnip pushing through. Once the radishes become big enough to eat, harvest them and thin the parsnip seedlings to10cm (4”) apart.
Maintenance
Once germinated, parsnips need virtually little help in getting along. Just keep them weed-free (by hand if possible, to avoid scoring the roots).
Harvesting
Harvest 8 months from the time of sowing and after the first frost. If your soil is loose enough, simply pull them up. If not, use a fork to carefully lift them. Parsnips store well in the ground, so if you’re not wanting to store them inside, simply harvest at need. In the UK, parsnips usually keep all winter long and into the spring. Once new growth begins to appear, harvest the remaining roots, as they’ll soon lose flavour.
Companion Planting
Parsnips combine well with onions, garlic, leeks, and leaf lettuce.