Gadenin日本語Get the appThink in years, not in a season
Unlike a bulb onion, this plant is not building towards one harvest and then dying. It builds a clump, divides itself at the base, throws a flower head in its second spring and keeps widening until the center gets congested. Your job across the year is to keep cutting it, keep it fed, take the flower stalks off unless you want seed, and break the clump up before it strangles itself.
A well managed clump gives its best from its second through its fourth year. After that the center goes woody and the shanks thin, which is your signal to divide rather than a sign of failure. Plan on dividing every three years and you will never see the plant decline.
Spring: growth, flower stalks and the main division
As soon as the soil warms above 45F (7C) the clumps come away fast, and this is the heaviest growth of the year. Pull back any winter mulch so the crowns get light and air, top dress with compost and give a nitrogen feed, and take your first cut once the leaves are eight inches (20 cm) tall.
Round hollow flower stalks with a swelling near the tip appear in the second spring and every spring after. Cut them out at the base as soon as you can see them unless you want seed, because a clump that flowers puts its energy there, the shanks go hollow and hard, and the eating quality drops for the rest of the season. Early spring is also the best moment to divide, since the plant is about to grow and will re establish in weeks.
If you do want seed, leave two or three stalks on one clump and cut the rest. A single head produces far more seed than a garden needs, and letting a whole bed flower costs you a season of eating.
Summer through autumn: cut, feed, earth up
Through summer the pattern is a cut every three to four weeks, a liquid feed after every second cut, and an inch or two of soil drawn up the row every couple of weeks while the plant is growing. In real heat growth slows and flavor gets stronger, so cut less often and water deeply rather than pushing it.
Autumn is the best eating of the year. Cool nights make the shanks sweeter and thicker, the pests have mostly gone, and blanching works well in soil that is damp but not sodden. This is also the window for an autumn division in mild areas, which gives the divisions six or eight weeks to root before cold stops them.
| Time of year | Main job | Cutting | Feeding |
|---|---|---|---|
| Early spring | Uncover crowns, divide clumps, remove flower stalks | First cut at eight inches (20 cm) | Compost top dress plus nitrogen |
| Late spring | Earth up every two to three weeks | Every three weeks | Liquid feed after every second cut |
| Summer | Water deeply, watch for thrips | Every four weeks | Light, avoid pushing soft growth |
| Autumn | Earth up, divide in mild areas | Every three to four weeks, best quality | One compost top dress |
| Early winter | Hard cut and mulch in cold areas | One heavy cut before hard frost | None |
| Deep winter | Leave alone, clear fallen leaves | Light cuts only in mild areas | None |
Winter, and how much cold this plant takes
Welsh onion is genuinely hardy and survives well below freezing, dying back to the crown and coming again. In cold areas take one heavy cut before the ground freezes, then mulch over the crowns with two to three inches (5 to 8 cm) of straw or leaves. The mulch is there to stop repeated freezing and thawing lifting the crowns out of the soil, which does more damage than cold itself.
In mild areas the plant hardly stops and you can keep cutting lightly all winter, accepting six to eight weeks between cuts. In containers it is more vulnerable, because the roots freeze from the sides as well as the top, so move pots against a wall or sink them into a bed for the coldest weeks.
Dividing a clump: the whole method
Keep one written record above all others for this crop: the date each clump was planted or last divided, and where it is. A perennial bed becomes untraceable within two years otherwise, and the difference between a clump that needs dividing and one that needs feeding is almost entirely a question of its age. Add the date of the first flower stalk and the dates of your cuts, and after two seasons you will have a calendar built out of your own garden rather than out of general advice.
- Lift the whole clump with a fork Loosen all round it and lift it entire in early spring or early autumn. Do not try to pull individual shanks out of standing ground, you will snap the plates off.
- Wash or shake the base clean Get the soil off so you can see where the individual plates and their roots are. Working blind you cut through plates and lose plants.
- Pull the clump apart by hand Work it into pieces of three to five shanks each, each with its own roots. Fingers, not a knife. A clump three years old gives fifteen to thirty usable pieces.
- Discard the woody center The oldest material in the middle is hard, hollow and unproductive. Throw it away and keep the vigorous outer pieces.
- Trim, then replant in fresh ground Cut leaves back to five inches (13 cm) and roots to an inch (2.5 cm), then plant the pieces six inches (15 cm) apart in a fresh trench. Do not put them straight back where they came from.
- Water once, then wait Water in and leave them alone. New growth in two to three weeks, and a first cut about eight weeks after dividing.