By Larry Hodgson
Question: This is my second gardening experience, but this year, my turnips didn’t produce a bulb, only a relatively thin root with lots of smaller roots, much like a hairy carrot. Where did I go wrong and what should I do to prevent this next time?
Answer: The turnip (Brassica rapa) is a fast-growing vegetable, usually harvested 35-60 days after sowing. It’s grown mostly for its swollen bulb-like root, so when it only produces an inedible fibrous root, that’s obviously a big disappointment.
There are several factors that could explain why your plants didn’t produce the globular root you expected. Here are a few :
Too Much Nitrogen: Soil too rich in nitrogen tends to give turnips with an abundance of foliage, but an underdeveloped root. This could have happened if you applied a very nitrogen-rich fertilizer or a heavy application of fresh manure or compost. If you apply such a product in the future, wait until the second year before sowing turnips. Or, make the application in the fall so there will be less nitrogen in the soil the following spring when you sow the seeds.
The Soil Was Just Too Hot: Turnips, like most root vegetables, prefer their soil cool. So, a serious heat wave can interfere with the formation of a nice round root. Sometimes, overheated turnip plants go straight to seed with producing anything like a thick root.
To try to avoid this, always sow turnips early in the spring, about 2–3 weeks before the last frost date, so that they can benefit from soil that is still fairly cool, then mulch their soil thoroughly as the leaves of the seedlings start to reach about 2 inches (5 cm) in height. Mulch will help keep the soil cool and moist.
Another possibility is to do the opposite and sow later, much later! That is, in late summer or early fall, for a late harvest, just before the ground freezes. With fall temperatures usually dropping bit by bit, turnips are often easier to grow in the fall.
… That turnips are not only white with purple shading at the top (the usual color in supermarkets), but can also be white, purple, red, green, yellow or even black?
Insufficient Watering: Turnips do best in soil that is always at least slightly moist. If they are subjected to drought, especially early in the season, that can interfere with the formation of a globular root.
Heavy Soil: Turnips prefer fairly light soil. If your soil is too heavy, dense, or rocky, the root may not develop well. Depending on your conditions, you may find your turnips do better in a raised bed filled with quality soil.
Transplantation: Turnips have little tolerance for transplanting. Even the slightest damage to the initial taproot can prevent it from producing a round root. This is one vegetable you should not sow indoors for transplanting to the garden, nor should you consider moving seedlings sown outdoors to another part of the garden.
Some Turnips Just Don’t Produce a “Bulb”: Most turnip seed sold for home gardens, at least in North America, is of the globular type, but in other parts of the world, long turnips, rather like an especially thick carrot, are popular. Also, there are turnip varieties grown strictly for their edible foliage, usually sold as “turnip greens”. They produce only narrow, tough roots with only the slightest suggestion of swelling. This includes varieties like ‘Seven Top’, ‘Alltop’ or ‘Topper’ that Maybe you purchased long turnip or turnip greens seeds by accident? Usually this detail is illustrated on the seed pack to avoid confusion. If so, next time, choose a turnip is a matter of choosing the desired shape accordingly when purchasing your seeds.
Good luck with your next turnip crop!