Gadenin日本語Get the appSow into falling heat, not rising heat
This is a turnip-family brassica grown for a big rosette of long leaves, and it needs roughly sixty to eighty days of cool, shortening days to build one. That fixes the sowing window tightly: begin as soon as the worst of the summer heat breaks and daytime temperatures settle below about 80F (27C), and finish about eight to ten weeks before your first hard frost. Sown into that window the plant never receives a signal to flower, and it simply piles on leaf until the cold stops it.
Sowing earlier is the common mistake. Seed put in while nights are still above 68F (20C) germinates in three days and grows fast, but the plants run out of season on the wrong side, sitting at full size through weeks of warmth and then bolting the moment spring arrives. Sowing later is the other failure: a plant that has not reached about ten inches (25 cm) across before day length drops under ten hours will sit at that size all winter, because growth effectively stops regardless of how mild the weather turns.
Seed germinates between 46F and 95F (8C to 35C) and comes up in three to five days at 68F (20C). Sow half an inch (12 mm) deep in soil that is damp all the way down. In late summer the top inch of a bed dries within hours, so run water into the open drill, let it soak away, sow into the wet bottom and cover with dry soil. That single habit is worth more than any amount of watering afterwards.
| Soil temperature | Days to emerge | What to expect |
|---|---|---|
| 50F (10C) | 8 to 12 | Even stands but too late to size up before the light goes |
| 60F (15C) | 4 to 6 | Ideal; steady growth into cooling weather |
| 68F (20C) | 3 to 5 | Fast and reliable, the usual late summer case |
| 80F (27C) | 3 | Quick but leggy; flea beetles find the row within days |
| Above 86F (30C) | Patchy | Poor stands and stressed seedlings; wait for the heat to break |
Spacing decides the size of the plant
A well-grown plant of this crop is large. Expect a rosette twenty to thirty inches (50 to 75 cm) across with leaves eighteen to twenty-four inches (45 to 60 cm) long, standing more upright than a lettuce and heavier than it looks. Because you cut the whole plant at the base rather than picking leaf by leaf, the plant size is the harvest unit, and spacing is what sets it.
Sow in stations rather than a continuous drill. Put four or five seeds in a shallow pinch at each station, with stations twelve inches (30 cm) apart in rows eighteen to twenty-four inches (45 to 60 cm) apart. Station sowing means each spot is guaranteed to have a plant, and thinning down to the strongest one is straightforward.
You can grow it much closer, at four to six inches (10 to 15 cm), and treat it as a cut-and-come-again leaf crop, but then you are growing a different vegetable. Crowded plants make narrow leaves with thin midribs, and the thick crisp leaf stalks that make this crop worth growing never develop. If you want the real thing, give it the room.
| Growing style | Final spacing | Days to harvest | Result |
|---|---|---|---|
| Full-size plants | 12 in (30 cm) apart | 60 to 80 | One large rosette per station, cut whole |
| Close-grown | 6 in (15 cm) | 45 to 55 | Smaller plants, thinner stalks, earlier cut |
| Leafing bed | 3 to 4 in (8 to 10 cm) | 30 to 40 | Young leaves for cooking; no thick stalks |
Thin in three stages
Thinning this crop is not one job, it is three, and doing it gradually rather than all at once protects against losses. Seedlings are the most attractive thing in the garden to flea beetles and slugs in late summer, and keeping spare plants at each station until the danger has passed costs you nothing.
At the first true leaf, reduce each station to three seedlings. When the plants have three or four true leaves and are around three inches (8 cm) tall, take each station down to two. Finally, when the leaves of neighboring stations begin to touch, cut back to the single strongest plant. Everything you remove after the first round is usable in the kitchen.
Cut thinnings off at soil level with scissors instead of pulling them. At this spacing the roots of the seedlings in one station are wound together, and pulling one lifts and loosens the one you meant to keep. Firm the soil back with your fingers afterwards and water the station in.
- Prepare the bed before the heat breaks Fork three inches (8 cm) of well-rotted compost into the top eight inches (20 cm) and rake it level a week ahead. The sowing window is short, and you want to be able to sow the day the weather turns rather than starting soil work then.
- Put mesh over the row at sowing Fine insect mesh on hoops, edges buried all the way round, is fitted the day the seed goes in. Late summer seedlings of this family are found by flea beetles within days, and cover applied after damage appears is already too late.
- Shade the row for the first week A length of shade cloth or an old net curtain laid loosely over the drill keeps the surface from baking while germination happens. Take it off as soon as the seedlings are through, or they stretch.
- Record the sowing date at each station Write down the date and how many stations went in. Compared against the date you finally cut, it gives you the true days-to-harvest for your own soil, which is what you use to set next year's sowing date.
Do not transplant this crop if you can avoid it. It has a taproot that resents disturbance, and transplanted plants stay smaller and run to flower earlier than direct-sown ones in the same bed. If you must raise plants in cells, use deep cells and set them out before they are three weeks old.