Parsnips (Pastinaca sativa) look like colorless carrots, but they have their own complex, sweetly spicy earthiness. And these annual root vegetables are even easier to grow than carrots, a close relative. Parsnips are native to Eurasia and have been a popular European food since at least the ancient Romans. The early English settlers brought parsnips with them to America, but they have since been overshadowed by both carrots and potatoes.
Parsnips grow well in most regions, although they require a long growing season and have the best flavor when they can be grown during relatively cool months. It can take from 120 to 180 days for parsnips to go from seed to harvest, so in many regions, they are grown as a winter crop, planted in the middle of the fall and harvested in late winter or early spring. In cold regions where the ground freezes solid, parsnips are planted in the early spring as soon as the ground can be worked, and harvested the following fall.
How to Plant Parsnips
Parsnips are grown predominately for their long taproots, which look like pale carrots. Unlike many vegetables, parsnips can be tricky to plant and grow. In some cases, they can take a full four months to fully mature.
Sow the seeds about 1/2 inch apart and 1/2 inch deep into healthy, thoroughly loosened soil. They can be planted a full two weeks before the last expected frost date—as soon as the soil can be worked in the spring. Once the seeds start to sprout growth, thin the plants to a spacing of 3 to 6 inches apart. When thinning, cut off the plants at ground level rather than pulling them, to avoid disturbing the surrounding plants.
For the first weeks, you may not see much growth, and that's totally normal. However, during this time, make sure there aren't any weeds around, as those will inhibit your parsnips' ability to thrive in the garden.
Though parsnips prefer full, bright sunlight, they can tolerate part shade.
Ideal soil conditions are deep, rich, and loamy. Parsnips prefer a slightly acidic to neutral pH—6.0 to 7.0. Also, try to make sure there are no rocks in the soil because they can break the roots. Thoroughly loosening the soil down to 12 inches will ensure good growth for parsnips and other root vegetables.
Parsnips love water and lots of it. Watering encourages strong and consistent root growth. When you go to water your parsnips, give them a good drink, but try to water them slowly rather than drenching them within a few seconds. Water your parsnips every 10 or so days.
Temperature and Humidity
Parsnips grow best in an environment where the average temperatures are between 45 and 70 degrees Fahrenheit. They will tolerate freezing temperatures at both the beginning and end of the growing season. In warm-climate zones, parsnips are often grown during the cooler winter season. Parsnips have no preference when it comes to air humidity.
Fertilize parsnips by side-dressing the plants at midseason with a granular all-purpose fertilizer. Parsnips require a lot of nitrogen, but only a little bit of phosphorous and potassium.
Varieties of Parsnips
- 'All American' is very sweet and fine-grained with a small core.
- 'Hollow Crown' has a mild honey flavor and uniform roots with few side roots.
- 'Harris Model' appears earlier in the season with tender flesh and no hollow crown.
- 'The Student' has large roots with a mild, nuttiness. They require a long growing season of about 180 days.
- ‘Avonresister’ is a short variety good for small spaces. It has good resistance to canker disease.
- ‘Cobham Improved Marrow’ produces 8-inch roots with a particularly sweet flavor.
- ‘Gladiator’ is a canker-resistance variety that produces very thick roots.
Parsnips require the entire growing season to mature, about four months. When planted in spring, they are usually harvested in late fall. Most varieties will have roots that reach 8 to 12 inches in length. To ensure you get the whole root, loosen the soil with a fork before harvesting.
You can leave your parsnips in the ground to harvest throughout winter (if the soil is not frozen) and into the early spring. They sweeten toward spring, as the plants get ready to begin growing again. However once the tops re-sprout, the flavor starts to go downhill and the roots get tough and fibrous. Harvested parsnips will store for a long time.
Carrot flies lay their eggs on the soil near plants and larvae burrow into the roots. Don't plant near carrots or celery and consider planting some onions nearby, which will discourage many pests. Celery flies give your plants small brown blisters. It won't harm the roots, but remove the leaves to get rid of the maggots. Wireworms will make small regular holes.
Canker is a plant disease that causes dark patches on the root's shoulders. It mostly affects injured roots. If canker is a problem, choose resistant varieties of parsnip. Leaf spot also causes small brown spots on leaves, but these won't affect the roots.