Gadenin日本語Get the appYou are planting bulbs, not sowing seed
Bunching shallot is a shallot-onion hybrid grown for its green tops, and it is set out as small dormant bulbs about the size of a thumbnail. It does not come true from seed, and in most gardens it never produces usable seed at all, so every plant in your bed traces back to a bulb somebody lifted and dried. That is not a limitation. It is the reason a single row planted once can supply green onions indefinitely.
Each bulb you push into the soil does not stay one plant. Within a few weeks it divides underground, and by the end of the growing season that one bulb has become a clump of six to a dozen shoots standing shoulder to shoulder. Plan the spacing for the clump, not for the bulb, or the bed closes over and the middle of every clump goes thin and yellow.
If you are used to planting onion sets, note the difference: an onion set swells into one large bulb, while a bunching shallot bulb multiplies sideways into many small ones. Never space it like an onion.
Plant in autumn, into ground that has already cooled
The main planting goes in during autumn, once the heat has broken and the soil has dropped to around 68F (20C) or below. Bulbs pushed into hot soil sit and rot rather than rooting. Wait for the point in autumn when nights are noticeably cool and the soil no longer feels warm to the back of your hand at a spade's depth.
Roots go down through the cooling weeks and the tops make most of their growth through autumn and again as soon as the worst of winter releases. In a mild climate the clumps stay standing and cuttable right through the cold months. Where winters are hard the tops die back to the ground, but the bulbs survive under a couple of inches of mulch and come away early in spring, well ahead of anything you could sow.
A second, smaller planting in late winter or very early spring works if you missed the autumn window, but those clumps split less and give you a lighter harvest before summer dormancy stops them.
| Planting factor | Target | What goes wrong outside it |
|---|---|---|
| Soil temperature | Below 68F (20C) and falling | Warm soil rots the bulb before roots form |
| Planting depth | Tip just at or barely under the surface | Buried deep, the shoot is slow and the neck rots |
| Bulb spacing | Six inches (15 cm) apart in the row | Closer and the clumps crowd into each other by spring |
| Row spacing | Twelve inches (30 cm) | Tighter rows are impossible to weed once clumps close |
| Bulbs per station | One or two | Three or more and the clump chokes itself in one season |
| Soil pH | 6.0 to 7.0 | Acid soil gives pale, thin tops that never thicken |
Depth is the part most people get wrong
Plant shallow. The bulb should sit with its shoulders in the soil and the pointed tip level with the surface or only just covered. This feels wrong to anyone used to burying garlic, but a bunching shallot bulb that is buried two or three inches down pushes a long white neck up through the soil, and that neck is exactly where rot starts in wet weather.
Press each bulb in point upwards with your thumb rather than dropping it into a hole, so the base is in firm contact with soil and there is no air pocket underneath. An air pocket under the base plate is the other common cause of bulbs that simply never root.
- Prepare loose, free-draining ground Fork the bed over and break up any pan. Bunching shallot roots are shallow and fine, and they will not push through compacted soil. Raise the bed three or four inches (8 to 10 cm) if your ground stays wet in winter.
- Work in compost, not fresh manure Spread an inch (2.5 cm) of well-rotted compost and fork it into the top few inches. Fresh manure gives soft, sappy tops that flop and attract thrips, and it raises the risk of neck rot.
- Set the bulbs point up, six inches apart Push each bulb in until the shoulders are covered and the tip shows. Firm the soil around it with your fingers so it cannot lift as roots push down.
- Water once, then leave it alone Give one good watering to settle the soil around the base plates. After that, keep the bed only just damp until you see green tips. Wet, cold, bare soil with no leaves drawing water from it is the ideal setting for rot.
- Mark the row before the tops appear Push in labels or canes at both ends. For two or three weeks there is nothing above ground, and an unmarked row gets hoed or dug by mistake more often than you would think.
Write down what you planted and where
This is a crop you will still be growing in five years from the same stock, so the planting record is worth more here than in almost any annual vegetable. Note the date you planted, the position of the row, how many bulbs went in and how big they were. When you lift and split the clumps the following summer you will want to know exactly how long that increase took and which end of the row did best.
Also record where the bulbs came from, whether you dried them yourself or bought them in, and how large each one was at planting. Bulb size at planting is the single best predictor of how many offsets you get, and after two seasons of records you will know precisely which size to keep back for replanting and which to eat.
Do not replant into the same ground where any onion, leek, garlic or shallot grew in the last two years. White rot and stem nematode both build up in allium ground and neither can be cured once the bed is infested.