Parsnips need well-prepared, low-nitrogen soil to grow straight roots
Question: Help! Our parsnips are terrible this year. We dug them up last week, only to discover the taproots are forked and crooked and covered with lots of little hair-like roots. They are very difficult to peel. We planted them by seed in early June and were sure to water them whenever the garden was dry. The tops got really nice, but the roots are terrible. We've never had this problem before and hope to avoid having the same experience next year. What happened?
Answer: Parsnips ( Pastinaca sativa) are close relatives of carrots. Their slender, white roots are surprisingly delicious roasted or pureed. The flavor is sweetened by cold weather and frosts, so this crop is often planted in summer and harvested late in the season. They take more than 100 days to reach maturity, but if they're protected with a heavy layer of straw, parsnip roots can be harvested all winter long, adding homegrown flavor to winter soups and stews.
Parsnip seeds can be sown anytime from early spring through midsummer for autumn and winter harvests. To keep the roots from forking, take care in preparing the seedbed prior to planting. Till the bed by hand or with a rototiller down to a depth of 2 feet, being sure to break up any lumps of soil and remove any rocks. Don't till the soil when it's too wet or clods will form and cause misshapen roots. Careful preparation is essential for straight root formation.
Fresh seed should be used every year as the seeds lose viability with age. You can soak the seeds in tepid water for a few hours before planting to speed germination. Seeds are sown 1⁄2-inch apart and 1⁄2-inch deep and may take two weeks or more to germinate. The resulting seedlings should then be thinned to a spacing of 3 inches on center when they are about an inch tall. This gives the roots ample room to grow and prevents them from competing with each other for nutrients, water and space.
Walking on the seedbed anytime during the parsnips' growth can compact the soil and cause the roots to buckle or fork. So, too, can inconsistent watering practices. Mulching your parsnip bed with shredded leaves, straw or finished compost will help keep the soil moist throughout the growing season. Be sure to deeply irrigate the roots if there is less than an inch of rain per week during the summer. Shallow, frequent irrigation is not nearly as useful as the occasional deep watering.
Forked and crooked roots also may be the result of carrot rust-fly maggot damage. To prevent this root-munching pest from nibbling on your parsnips, cover the growing plants with a layer of floating row cover. It can be placed over the plants soon after they are thinned and remain in place until harvest. Not only will it protect the roots from this pest, it will also shelter them from weather extremes.
And lastly, forked roots with lots of fine root hairs are often a sign of high soil nitrogen levels. Parsnips do not like fertilizers with excessive nitrogen. Do not add a nitrogen-supplying fertilizer or manure to the garden area before planting your parsnips.
Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio with Doug Oster. She is the author of several gardening books, including “Attracting Beneficial Bugs to Your Garden: A Natural Approach to Pest Control” and “Good Bug, Bad Bug.” Her website is jessicawalliser.com.
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