Gadenin日本語Get the appSow after the longest days, not before
Endive is grown for a dense, heavy heart, and a heart only forms properly while day length is shortening and nights are dropping. Sown in spring it behaves like a long-day plant that has been given exactly what it wants: it makes a rosette, then runs a flower stem straight up through the middle before there is anything worth cutting. The reliable window opens once the longest day has passed and stays open for about six weeks after that.
Count backwards from your first hard frost instead of forwards from a date. The curly frisee kinds need roughly 80 to 95 days from sowing to a full blanched heart, and the broad escarole kinds need 85 to 100. Add the two weeks the blanching itself takes and you want the seed in the ground about three and a half months before the ground freezes. That is late enough to avoid bolting and early enough that the plant has real size before growth slows.
A second, smaller sowing three weeks after the first is worth making. Endive stands in the ground for a long time once it is mature, but a blanched heart has to be used within about ten days, so two sowings give you two harvest windows rather than twenty heads all ready at once.
| Kind | Sowing window | Days to a full heart | What it is best at |
|---|---|---|---|
| Curly, finely cut leaves (frisee) | Early to midsummer | 80 to 95 days | Blanching to a pale, crisp center |
| Broad, flat leaves (escarole) | Midsummer to late summer | 85 to 100 days | Standing through frost and cooking |
| Either kind, cut small as leaves | Spring or late summer | 35 to 45 days | Cutting young before bitterness builds |
Depth, temperature and getting an even stand
The seed is small, pale and slightly ridged, and it needs a covering of a quarter of an inch (5 mm) at most. Half an inch (12 mm) is already too deep and you will get gaps in the row. Firm the base of the drill with the edge of a board so every seed sits at the same level, sow, then sift dry soil over and press it down with the flat of your hand.
Germination takes four to eight days at soil temperatures of 60 to 72F (15 to 22C). Above 80F (27C) germination goes patchy and slow, which is the real difficulty of a midsummer sowing into bare, sun-baked ground. Water the open drill and let it drain before the seed goes in rather than watering over the top afterwards, sow late in the day, and lay a board or a length of shade fabric over the row until the first pale loops of seedling show. Lift the cover the same morning they appear or they will stretch and fall over.
Endive transplants far better than chicory grown for a root, so raising the seedlings in cells and setting them out at four true leaves is a perfectly good route, and it keeps the bed free for something else through the hottest weeks. Sow two seeds a cell and pinch out the weaker one.
- Water the drill before sowing Run water along the open drill and let it soak away. Watering after sowing washes the light covering off and drags the seed into clumps at the low end of the row.
- Sow in stations, not a continuous ribbon Three seeds every 10 inches (25 cm), with rows 14 to 16 inches (35 to 40 cm) apart. Sowing thickly along the row wastes seed and makes thinning a much slower job.
- Thin at the second true leaf Leave the sturdiest seedling at each station and snip the others off at ground level rather than pulling them, so the survivor keeps its root run undisturbed.
- Set the final spacing before the leaves touch Aim for 10 to 12 inches (25 to 30 cm) between plants for curly kinds and 12 to 14 inches (30 to 35 cm) for broad-leaved ones. Once neighboring rosettes overlap it is too late to correct.
Thinnings are worth eating as small leaves while they are still mild, but do not leave two plants at one station hoping both will heart. Crowded endive makes a loose, airy center that will not blanch evenly and rots from the middle in wet autumn weather.
The bed and the feeding it needs
Endive is grown fast and eaten as leaf, so unlike a root crop it wants ground in good heart. Work in well-rotted compost a few weeks before sowing at about a bucketful to the square yard (square meter), and rake the surface to a fine tilth so the small seed makes contact everywhere. Ground that grew peas or beans earlier in the season suits it well.
The plant is shallow-rooted for its size and it will not stand a check. A dry fortnight in the middle of growth produces a small, tough rosette that never fills out, and a plant that has stalled once tends to run to flower rather than heart when growth restarts. Keep the soil evenly damp from sowing through to the start of blanching, and mulch between the rows with an inch (2.5 cm) of compost once the plants are established.
Feed once, about four weeks after sowing, with a nitrogen-leaning liquid feed. That single feed carries the plant through the leafy phase. Stop feeding once the heart starts to close, because soft, sappy leaves going into a blanching cover are exactly what rots.
Bolting: why an early sowing fails
The commonest failure with endive is a spring sowing that produces a flower stem instead of a heart. Two things trigger it: long days, and a cold check on a young plant. A seedling that sits through a run of nights below 50F (10C) after it has four or five true leaves reads that cold as a winter and flowers when warmth returns, exactly as a biennial is supposed to.
That is why late sowings succeed where early ones do not. A plant sown after midsummer meets its cold weather when it is already mature and past the stage where cold triggers flowering, so it simply sits and thickens. If you want an early crop, sow the same seed but plan to cut it small as loose leaves at 35 to 45 days and accept that no heart will form.
Once a stem starts to elongate the plant will not come back. The center goes hollow and the leaf turns genuinely, unpleasantly bitter rather than pleasantly so. Pull it, and note the sowing date so you can push the next one later.
What to write down at sowing
Record the sowing date, the kind sown, and where in the bed each row sits, then note the date the first true leaf appeared and the date you finished thinning. Those four entries are enough to reconstruct the whole season next year, and they turn a vague sense that something went wrong into a specific correction.
The entry that pays for itself is the sowing date set against whether the plants bolted. Two seasons of that pairing will tell you the exact week your garden can start sowing endive without losing plants to flower stems, which is a more useful number than any calendar can give you. Note the soil temperature at sowing as well if you take it; germination gaps almost always trace back to sowing into ground above 80F (27C).