Gadenin日本語Get the appThe squeeze test
Napa cabbage is ready when the head resists a firm push with an open hand and feels solid rather than springy. Start testing about three weeks after the youngest leaves begin standing upright, and test every few days after that. A head that gives easily is still filling and will gain noticeable weight in another week, so there is no reason to rush it.
Size is a poor guide on its own because it depends on how big a frame the plant built. A well-grown autumn head is usually three to five pounds (1.5 to 2.5 kg) and eight to ten inches (20 to 25 cm) tall, but a crowded plant may top out well below that and still be perfectly firm and worth cutting. Trust the feel.
| Sign | Meaning | Action |
|---|---|---|
| Head soft, gives easily to a squeeze | Still filling | Leave another one to two weeks, keep watering |
| Head firm and solid, outer leaves green | Ready | Cut within the next week or two |
| Head very hard, top leaves splaying or splitting | Past its best | Cut now, use soon, storage life is reduced |
| Outer leaves yellowing from the base | Plant finishing, or root problem | Cut and check the base of the stem for rot or maggots |
| Hard frost forecast | Head will freeze and go soft on thawing | Cut everything remaining, regardless of firmness |
Frost, and the end of the season
A light frost improves Napa cabbage, sweetening the leaves noticeably as the plant converts starch to sugars. Heads sit happily through a few nights around 28F to 30F (minus 2C to minus 1C) with only the outermost leaves damaged. This is worth waiting for if you can, because the difference in flavor after a couple of light frosts is real.
A hard freeze is a different matter. Once the head itself freezes solid, the tissue collapses on thawing, goes translucent and begins to rot within a day or two. Below about 25F (minus 4C) you are risking the crop, so get everything cut before a hard freeze is forecast. Gathering the outer leaves up over the head and tying them loosely buys you a few degrees and a few extra days.
Cutting properly
Cut in the morning after the dew has dried, when the head is fully turgid and cool. A sharp knife through the stem just below the bottom of the head is all that is needed. Do not pull or twist the plant out of the ground, because that tears the base and gives rot a starting point on a head you may want to store.
Leave two or three of the loose outer wrapper leaves attached even though they look untidy. They protect the tight leaves underneath from bruising and drying while the head is handled and stored, and you strip them off in the kitchen. A head cut clean and trimmed back to the tight leaves loses moisture from every cut edge and keeps much less well.
- Cut in the morning Wait until the dew has dried but the plant is still cool. A head cut in afternoon heat goes limp and never fully firms up again.
- Slice the stem cleanly below the head One clean cut with a sharp knife. A ragged or crushed stem base is where storage rot begins.
- Keep two or three wrapper leaves The loose outer leaves are packaging. Leave them on for handling and storage, and remove them only when you are about to use the head.
- Inspect the base and the top Check the cut end for maggot tunnels and the top of the head for slug entry. Anything with damage inside goes into the kitchen now rather than into storage.
- Clear the stump and the debris Pull the root and take the outer leaves off the bed. Left in place they carry aphids and caterpillars through to the next crop.
Storing for weeks, not days
A sound, dry head with its wrapper leaves on keeps for six to eight weeks at 32F to 36F (0C to 2C) with high humidity. That is a cold cellar, an unheated shed on the cold side, or the bottom of a refrigerator. Do not wash it before storing. Surface moisture between the leaves is what starts soft rot, so if the head came in wet, stand it somewhere airy until the outside is dry.
Store the heads upright and not touching, on a slatted shelf or in a crate, so air moves around each one. Check them over every couple of weeks and pull off any outer leaf that has gone slimy, because one rotting leaf will spread to the head beside it. Heads that were split, frosted hard or slug damaged never keep, so eat those first and store only the clean ones.
Napa cabbage picks up strong smells and it is sensitive to ethylene. Do not store it next to apples, pears or ripening tomatoes: the ethylene they give off makes the outer leaves drop and yellow within days.
Records that pay off next year
Write down the date you cut each head, its weight, and how firm it was. Put that alongside the sowing date from the same row and you have the actual days to maturity for your garden and your season, which is far more useful than the range printed on a packet. Two years of that and your sowing date stops being a guess.
Note the failures with equal care: which heads had tip burn inside, which had slug damage, which split. Note where in the row each one stood. Damage in Napa cabbage is usually patchy across a bed rather than uniform, and the pattern in the notes normally points at a real cause such as a dry corner, a shaded end or a strip that was mulched too close to the stems.