Gadenin日本語Get the appSow direct, never in modules
A turnip is a swollen taproot and hypocotyl. The moment that taproot is checked or bent it stops going down and the plant thickens sideways into a lopsided, forked or hollow root instead. Transplanting from a module does exactly that, which is why turnips raised in cells so often end up long and tapered rather than round.
Sow into the final bed and accept that the row will need thinning. Turnip seed is cheap, germination is fast and reliable, and sowing generously then removing surplus is far more productive than trying to place single seeds and living with the gaps.
The bed itself needs less preparation than a carrot bed because the root is shallow. Six to eight inches (15 to 20 cm) of loose, stone-free soil is enough. Take out clods and old root fragments in the top few inches and rake it level so the seed sits at an even depth.
Depth, temperature and how fast it comes up
Turnip seed germinates over a wide range and it is quick. In warm soil the row is visibly green in three days, and even in cool soil it rarely takes more than a week. If nothing shows after ten days the seed was sown too deep, the soil is too cold, or something ate the seedlings the night they emerged.
Cover with half an inch (1 cm) and no more. The seed is small and it does not have the reserves to push through an inch of soil. Firm the covering with the back of a rake so the seed is in contact with damp soil, then water with a fine rose.
| Soil temperature | Days to emerge | What to watch |
|---|---|---|
| 50F (10C) | Seven to ten days | Slugs eat the seedlings before you see the row |
| 59 to 68F (15 to 20C) | Three to five days | Nothing; this is the easy range |
| 77F (25C) | Two to three days | The surface dries out between waterings |
| Above 86F (30C) | Patchy and uneven | Sow later, or shade the bed until they are up |
Turnips are fast enough to be worth resowing. If a row comes up badly, do not nurse it along. Clear it, change one thing about the covering or the watering, and sow again the same week.
Spacing decides the size of the root
This is the one decision that matters most, and it is made before the seed goes in. Turnips do not have a fixed size that they grow to and stop at. They keep swelling until they run out of room or you pull them, so the spacing you thin to is the size you will be harvesting.
Decide which crop you want first. Small tender roots for eating raw and roasting whole come from close spacing and a short season. Larger roots for storing and for soups come from wide spacing, and they need the extra weeks to fill without going coarse.
| What you want | Final spacing | Row spacing | Roughly ready in |
|---|---|---|---|
| Baby roots, eaten whole | 2 in (5 cm) | 8 in (20 cm) | Five to six weeks |
| Standard eating size | 4 in (10 cm) | 10 in (25 cm) | Seven to eight weeks |
| Large roots for storing | 6 in (15 cm) | 12 in (30 cm) | Ten to twelve weeks |
| Leaves only, cut young | 1 in (2.5 cm) | 6 in (15 cm) | Three to four weeks |
Thin in two passes, not one
Thinning all at once at the seedling stage leaves you with nothing in reserve. Slugs, flea beetle and a bad patch of soil all take plants after thinning, and a gap in a row of turnips is a gap that never fills. Go through twice, and take a crop off the second pass.
- First pass at the seed leaves As soon as the round seed leaves have opened flat, thin so no two plants touch, about an inch (2.5 cm) apart. Pinch the surplus off at ground level rather than pulling, so you do not disturb the roots of the ones you are keeping.
- Second pass at two or three true leaves Take the row out to the final spacing from the table above. This is the pass that sets the size of the root, so measure it rather than eyeballing it. Remove anything crooked, pale or already chewed and keep the strongest plant in each gap.
- Eat the second thinnings Plants pulled at two or three true leaves are a salad crop in their own right. Whole seedlings, root and all, are mild and sweet, and this is the point at which most gardeners realize the tops are worth as much as the roots.
- Firm and water after each pass Press the soil back around the plants you have kept and water the row. Thinning loosens the neighbors, and a turnip whose root is left waving in an air pocket will sit still for a fortnight.
Never leave thinnings lying on the bed. The crushed leaves smell of brassica and pull cabbage root fly straight to the row. Take them off the plot or bury them.
Successional sowing, and what to write down
Turnips have a short useful window on the plate. From the point they are the right size, you have two or three weeks before the texture starts to coarsen. Sowing the whole packet on one day gives you far more turnips than you can eat in that window, and then a bed of woody ones.
Sow a short row every two to three weeks instead. A row of ten feet (3 m) at a time is enough for most households. Keep going through the cool half of the year at either end of summer, stop when the soil is consistently hot, and start again as it cools.
- Record the sowing date and the row Write down the date and which end of the bed each sowing went into. Turnips are fast enough that two sowings three weeks apart look identical from above until you pull one, and the roots go over quickly.
- Note the date the first root was ready Count the days from sowing to the first root worth pulling. That number is the single most useful thing you will know next year, because it lets you place a sowing to land at the exact week you want the crop.
- Note whether the sowing bolted Mark spring sowings that ran to flower rather than filling. The cut-off date between a sowing that bolts and one that does not is sharp, and it is specific to your plot.