Gadenin日本語Get the appWhy this crop is hilled at all
Hilling, or earthing up, means drawing loose soil from between the rows up against the base of each clump so that a greater length of the plant grows in darkness. On a pickling shallot the part you eat is the swollen bulb and the short white stem above it, and every inch of that which is covered stays pale, tender and mild. Every inch exposed to light turns green, firms up and takes on a coarse flavor that survives pickling badly.
There is a mechanical reason too. As the clump divides, the ten or more new bulbs push outward and upward against each other, and the whole cluster gradually lifts itself proud of the surface. Left uncovered, the shoulders green, the exposed bulbs dry unevenly, and the clump becomes unstable enough to rock in the wind and tear its own fine roots.
This crop is not blanched in the sense that celery or leeks are. You are covering an inch or two of shoulder and stem, not burying the plant. Soil piled over the growing point smothers the shoots and invites neck rot.
Hill twice, at the right two moments
Two hillings through the season are enough. The first goes on when the tops are six to eight inches (15 to 20 cm) tall and the clump has begun to widen visibly at the base, which in an autumn planting falls in the first part of the cool growing season. Draw soil up one to one and a half inches (2.5 to 4 cm) around each clump, leaving all the green leaf clear.
The second hilling goes on when the clump is fully formed and bulbs are swelling, before the tops show any sign of yellowing. Add another one to one and a half inches (2.5 to 4 cm), bringing the total covering to around three inches (8 cm) above the original planting level. Stop there. Hilling after the tops start to yellow does nothing useful, because the bulb has finished lengthening and is now drying down, and the extra damp soil around a dying neck is a direct invitation to rot.
Work when the soil surface is dry and crumbly rather than after rain. Wet soil packs into a hard collar around the necks as it dries, and that collar holds moisture exactly where you least want it.
| Hilling | Timing signal | Soil added | Purpose |
|---|---|---|---|
| First | Tops six to eight inches (15 to 20 cm) tall | One to one and a half inches (2.5 to 4 cm) | Starts lengthening the white stem, steadies the clump |
| Second | Clump wide, bulbs swelling, tops still green | One to one and a half inches (2.5 to 4 cm) | Covers rising shoulders, keeps them pale |
| Extra, cold climates | After the first hard frost | One inch (2.5 cm) plus loose mulch | Insulates the bulbs through winter |
| None wanted | Tops beginning to yellow | Nothing | Bulb has stopped lengthening; soil now causes rot |
How to draw the soil up without damaging roots
The roots of this crop are fine, shallow and spread further sideways than the clump looks, so a hoe driven in close does real damage. Take your soil from the middle of the space between rows, not from right beside the plants, and use a draw hoe pulled gently rather than a chopping stroke.
- Weed the row first Hilling over weeds buries them at the base of the clump where you cannot reach them, and they come up through the ridge within a fortnight. Hand-pull close to the plants and hoe only the middle of the row.
- Loosen the soil between the rows Break the surface crust in the center of the alley with a hoe or cultivator so the soil is crumbly and moves easily. Do not go deeper than an inch or two (2.5 to 5 cm) anywhere near the plants.
- Draw soil towards the clumps from both sides Pull loose soil up against the base of each clump from one side and then the other, forming a low continuous ridge along the row rather than individual mounds.
- Keep every green leaf above the soil Run a finger down into the ridge and check that the covering stops where the leaves separate from the neck. If soil has fallen into the middle of a clump, tip it out.
- Firm the ridge lightly and check after rain Pat the ridge just enough that it holds shape. Heavy rain washes ridges flat, so walk the row afterwards and draw the soil back up where the shoulders have been exposed.
Reading the result at lifting time
When you lift the clumps in early summer, the hilling shows immediately. Well-hilled bulbs have a white stem of an inch or more (2.5 cm or more) above the swollen part, a clean pale shoulder, and a smooth skin that peels off in one piece. Under-hilled bulbs have green shoulders, a short stub of stem, and a skin that clings in patches where the sun caught it.
Green shoulders are not spoiled and can be trimmed away, but you are cutting off part of what you grew, and the trimmed surface means the bulb will not keep even the few days it otherwise would. If a whole row shows green shoulders, the fix next season is an earlier first hilling rather than a deeper second one.
Note the dates of both hillings alongside how the bulbs looked when lifted. Two seasons of that comparison tells you whether your first hilling is going on too late, which is by far the commonest error and the easiest to correct.
In containers, hilling means topping up with more potting mix rather than drawing soil sideways. Leave three inches (8 cm) of space below the rim at planting so you have room to add it later.