Gadenin日本語Get the appThe shape of a celery year
Celery is a long crop by any standard: five to six months from sowing to the first cut, of which the first ten to twelve weeks are spent under cover as a seedling. It is not a crop you can slot into a gap. Plan the bed for it before the season starts, because it will still be occupying that ground when the frosts arrive.
The year divides cleanly into five stretches, and each has one decision that carries more weight than everything else in it. Knowing which one it is stops you fussing over things that do not matter and missing the thing that does.
| Stretch of the year | What you are doing | The decision that matters |
|---|---|---|
| Late winter, under cover | Sowing and germinating | Holding 68F (20C) for three weeks |
| Early spring, under cover | Transplanting seedlings, growing on | Not letting the seedlings get cold |
| Late spring | Hardening off and planting out | Waiting until nights hold above 50F (10C) |
| Summer | Watering, feeding, weeding | Never letting the soil dry |
| Early autumn | Blanching and harvesting | Starting blanching early enough |
Late winter to spring: under cover
Sow about ten to twelve weeks before your last expected frost, on the surface of a firmed tray, uncovered, at 68F (20C). Expect two to three weeks to germination and do not resow in the meantime. Transplant into individual cells at the first true leaves and keep the plants growing steadily at 59F to 68F (15C to 20C).
The trap in this stretch is cold. A young celery plant that spends ten days or more below 50F (10C) will flower rather than build a head, and it does so months later when you have forgotten the cold snap. That means resisting the urge to move trays into an unheated greenhouse in early spring, and it means checking the forecast rather than the calendar before hardening off.
Prepare the bed while the plants are growing. Dig in as much well rotted manure or compost as you can spare. Celery wants ground that holds water like a sponge, and this is your only chance to build that in.
Sowing a second batch two to three weeks after the first is cheap insurance. If the first is caught by cold, the younger plants are usually less sensitive and you still get a crop.
Late spring to midsummer: planting and building growth
Plant out once nights are reliably above 50F (10C), after a full ten to fourteen days of hardening off. Set plants at the same depth they grew in their pots, nine to twelve inches (23 to 30 cm) apart, closer and in a block for self-blanching types so they shade one another. Water them in thoroughly and keep them wet for the first fortnight while they root out.
From then until late summer the work is repetitive and unglamorous, and it is the whole crop. Water deeply two or three times a week, more in heat. Mulch. Liquid feed every two to three weeks. Hoe shallowly or hand weed, because deep hoeing cuts the surface roots that celery depends on. Pull off yellowing outer leaves as they appear.
- Water in and keep wet for two weeks New plants have almost no root reach. Daily checks for the first fortnight, and water before the surface dries rather than after.
- Mulch once the plants are away Two inches (5 cm) of compost or straw around each plant, kept clear of the stems. This halves your watering and keeps the shallow roots cool through summer.
- Feed every two to three weeks A liquid feed with nitrogen through the main growing period keeps the stalks swelling. Pale lower leaves mean you have left it too long.
- Get through the hottest fortnight Above 77F (25C) growth stalls and bitterness sets in. Extra water and some afternoon shade over the bed are the only useful responses, and they are worth the effort.
- Watch for leaf spot after wet spells Brown speckled patches on the older leaves spread upwards in damp weather. Remove and bin affected leaves early rather than waiting to see how bad it gets.
Late summer to the frosts: blanching and cutting
When plants reach around twelve inches (30 cm) and are growing strongly, start blanching if you are going to. Draw soil up to a third of the height, or fit a collar of thick paper or cardboard, and repeat in two or three stages every two to three weeks. Count three to five weeks from the first earthing up to a head worth cutting.
Keep watering right through this stretch. Blanching reduces the leaf area doing the work, and a plant that dries out while blanching gives you pale stringy stalks, which is the worst of both outcomes.
Harvest from early autumn once the base is six to eight inches (15 to 20 cm) across. Light frost improves the flavor and celery stands it well, so there is no rush in mild weather, but cut everything before a hard freeze because frozen stalks collapse as they thaw. Then clear the ground completely: every leaf and root stub left behind carries leaf spot into next year. Do not compost celery debris, and do not put celery back in the same bed next season.
Record the sowing date, the planting-out date, the coldest night the young plants saw, the date you started blanching and the date of the first cut. Those five dates, set against how the stalks eat, tell you exactly what to change next year, and it is the only way to move from general advice to what your own garden actually needs.