Gadenin日本語Get the appJudge by height, not by the packet
The usable window runs from about three inches (8 cm) tall for salad up to about twelve inches (30 cm) for full plants. Within that range nothing is wrong; the leaf simply changes character. Small leaves are tender, mild and go in raw. Big leaves have thick pale stalks that stay crisp when cooked and a definite mustard warmth.
Days to harvest is only a rough guide because temperature swings the rate enormously. The same sowing that gives you a cutting crop in twenty days in warm weather takes six weeks in the cold. Look at the plant.
Harvest in the morning if you can. Leaves cut in the cool of the morning are full of water and stay crisp for days; the same plant cut on a hot afternoon goes limp before you get it indoors and never fully recovers.
| Plant height | Stage | Best use | How to cut |
|---|---|---|---|
| 3 to 4 in (8 to 10 cm) | Baby leaf | Raw in salad | Shear the whole stand at once |
| 6 to 8 in (15 to 20 cm) | Medium | Quick cooking, soups | Cut whole plants or pick outer leaves |
| 10 to 12 in (25 to 30 cm) | Full size | Stir frying, braising, pickling | Cut the whole plant at the base |
| Over 14 in (35 cm) | Past its best | Stems only, cooked long | Clear the row and sow again |
Three ways to take the crop
Which method you use is a decision about time, not about the plant's welfare. All three work; they just spread the yield differently across the weeks.
- Whole plant harvest Cut through the stem at soil level with a knife, keeping the plant intact so the leaves stay clustered. This gives the best-looking bunches and the thickest stalks, but the ground is then empty and you need another sowing to follow it. Use it for the main crop rows.
- Outer leaf picking Snap or cut the three or four largest outer leaves from each plant, leaving at least five or six central leaves standing. The plant keeps growing from the middle and you come back every four or five days. One row picked this way feeds a household far longer than the same row cut whole.
- Cut and come again Shear the whole stand across at one inch (2.5 cm) above the soil, above the growing point. New leaves push from the stubs within a few days and the next cut is ready in two to three weeks. Expect two or three cuts before the regrowth turns narrow and hot.
- Whichever you use, clear the debris Take cut stems and damaged outer leaves off the bed rather than dropping them between rows. Rotting brassica leaves attract slugs and give downy mildew somewhere to sit through a wet week.
What you lose by leaving it too long
Komatsuna does not collapse if you leave it, which is part of why it is easy to grow, but it changes. Past about fourteen inches (35 cm) the leaf blades coarsen, the ribs turn fibrous, and the mustard heat that was pleasant at eight inches (20 cm) becomes the dominant flavor. In warm weather an overmature plant also starts to elongate at the center, which is the first move towards flowering.
The stems remain good long after the leaves have gone tough. A plant that has run past the salad stage is still worth cutting for its pale midribs, sliced and cooked the way you would use a stem vegetable. Nothing here needs to go on the compost pile uneaten.
Cold changes it in the opposite direction. Plants standing through frost concentrate sugars in the leaf and get noticeably sweeter and less sharp. A row that has been frosted two or three times is at its best, which is why the cold-season crop is the one worth growing for flavor rather than speed.
If a plant has bolted and thrown a flowering shoot, cut the shoot while the buds are still tight and green. It cooks like a small sprouting broccoli and is one of the better things the plant produces.
Keeping it after you cut it
Komatsuna wilts fast because the leaves are thin and there is no waxy coating to hold water in. Get it out of the sun the moment it is cut. A bucket with an inch (2.5 cm) of water in the bottom, stood in the shade, holds a morning's picking without any loss.
In the fridge, wrap the leaves in a damp cloth or a sheet of damp kitchen paper, put the bundle in a loose bag and stand it upright rather than laying it flat. Stored that way it keeps five to seven days. Sealed dry in a tight bag it goes yellow and slimy in two.
For longer keeping, blanch for about forty seconds in boiling water, plunge into cold water, squeeze out hard and freeze in portion-sized balls. It holds for several months and comes out fine in anything cooked. Do not try to freeze it raw; the leaf structure collapses completely.
Record what you cut and when
Write down the sowing date, the date of the first cut and the height the plants had reached, for each row or pot. After two or three sowings across different seasons you will have your own figures for how long the crop takes in your garden in warm and in cold conditions, which is the number that actually lets you plan successions. Note also which rows you cut whole and which you picked over, and how many cuts each gave, because that varies far more with your soil and light than with the seed.