Sowing turnips: choose a season that suits the roots you want

Before sowing turnips, decide whether you want small, early roots or a larger main crop. Then match the seed type and sowing window to your local season and the moisture you can provide. The RHS turnip guide supplies the UK sowing, spacing and harvest references below; other temperate regions need local timing.

Do you want early roots or a later maincrop?

An early crop is intended for young roots; a maincrop has more time to grow. The guide recommends outdoor sowing from March to June for early turnips, and from July to mid-August for maincrop turnips. These are UK windows, not dates to transpose to France or another region. Check the variety and your local growing conditions before sowing.

The RHS notes that hot, dry conditions can make roots woody or split, and that plants may bolt. Sowing dates cannot remove those risks on their own. Before choosing a window, consider whether you can monitor soil moisture through warm or dry spells and whether the variety's intended use fits the time available.

How can you choose a window without blending calendars?

The seed packet and local conditions matter more than a month copied from another climate. If the soil is still cold for an early sowing or summer heat is likely to dry the bed, adjust the window or choose a different crop. A beginner's vegetable-garden plan can help you fit early roots and maincrop turnips around the rest of your bed.

Turnips are Brassica rapa. Swede, also called rutabaga, is another Brassica species (B. napus); daikon is a radish. Keeping these names distinct prevents applying one crop's instructions to another.

What sowing and thinning method should you use?

For direct sowing, use a drill about 1 cm deep and rows 23–30 cm apart. Once seedlings are established, thin early turnip varieties to about 15 cm and maincrop varieties to about 23 cm between plants. Follow the seed packet where it gives variety-specific instructions. Thinning sets the intended spacing, but it is not a standalone cure for hollow roots or dry soil.

Keep the seed row moist while seedlings emerge, then check the soil around growing roots during dry spells. Water when that root zone is drying, allowing water to soak in rather than running off. Avoid a fixed number of litres or days: rainfall, soil, wind and exposure change the need. The guide to what to grow in a small garden can help you decide how much bed space to reserve.

When are turnips ready to harvest?

The guide gives around six weeks for some early types and about ten weeks for maincrop turnips, with timing affected by conditions. Treat these as estimates, not automatic harvest dates. Check the roots and harvest when they reach the size and use you want; leave a storage crop longer only if the variety and season suit that plan.

What can a hollow or fibrous root tell you?

A woody, split or hollow root is a reason to review the weather, moisture and harvest stage, but it does not establish one cause on its own. For a future sowing, choose the intended crop first, then a window suited to your region and a routine that lets you monitor soil moisture. That makes the choice more deliberate without promising a particular root quality.