Gadenin日本語Get the appThink in eight to ten week cycles, not in seasons
Kailan is fast. Sowing to first cut is 55 to 70 days for a standard crop and about 40 days for baby stems, and the side shoot run adds another four to six weeks after that. The consequence is that the crop does not fit the usual pattern of one spring sowing and one autumn sowing. It fits a rolling pattern of short sowings every two to three weeks from the moment soil reaches 50F (10C) until about ten weeks before hard frost.
Work backwards from when you want stems rather than forwards from a sowing date. If you want cutting to start eight weeks from now, sow now. If you want cutting to continue into the frosts, count ten weeks back from your expected first hard frost and make that your last sowing, accepting that the last one may only give a main stem and no side shoots.
The plants also arrive faster in heat than in cool. The same 60 day nominal crop takes about 50 days in a hot spell and 75 in a cool one, so successional intervals should tighten in summer and stretch in the shoulder seasons.
| Stage | Time from sowing | What to do |
|---|---|---|
| Emergence | 3 to 8 days | Keep the drill damp, mesh already in place |
| First thin | 12 to 16 days | Thin to 2 inches (5 cm), snip rather than pull |
| Final thin | 22 to 28 days | Thin to 6 to 10 inches (15 to 25 cm) depending on stem wanted |
| Nitrogen top dressing | Around 30 days | Liquid or granular feed 6 inches (15 cm) from the stems |
| Bud clusters visible | 45 to 55 days | Start walking the bed every two days; stop feeding |
| First cut | 55 to 70 days | Cut above a low leaf, feed and water the same day |
| First side shoot flush | First cut plus 10 to 21 days | Pick every two to three days, feed at half strength |
| Plant finished | First cut plus 4 to 6 weeks | Pull when shoots come pencil thin and flower at once |
The spring run: start as soon as soil hits 50F (10C)
The first sowing goes in as soon as soil at sowing depth holds 50F (10C) in the morning, which is usually a couple of weeks before your last frost date in a mild area and after it in a cold one. Keep row cover on this sowing until the plants have five true leaves. Kailan seedlings that sit through repeated nights under 50F (10C) are the ones that flower prematurely on a six inch (15 cm) stem, and that fault is created at the seedling stage and only shows up six weeks later.
Spring is the easiest season for stem quality, because the plants mature into rising warmth with plenty of soil moisture behind them. Expect the thickest stems of the year from sowings made in the first month of the season.
Sow again every three weeks through spring. As the weather warms the intervals shorten naturally because each crop runs faster, so by early summer you will find yourself sowing every fortnight to keep the supply level.
- Take the soil temperature before the first sowing Push a soil thermometer to 2 inches (5 cm) and read it early in the morning for three days running. Sow when all three readings are at or above 50F (10C).
- Row cover the first sowing to five true leaves Cold at the seedling stage causes premature flowering later. Row cover costs nothing and removes the single biggest risk to the spring crop.
- Sow the second row when the first has four true leaves Using the previous row as the trigger keeps the succession correctly spaced whether the season is running early or late.
Summer: this is where kailan earns its place
Kailan is the brassica that keeps producing through summer. It holds up at 85F (29C) and will give usable stems where broccoli buttons, cauliflower blinds and cabbage splits. If you grow one brassica through the hot part of the year, this is the one to grow, and it is the main reason to give it space.
Heat does cost you something. Stems come thinner, flavor turns sharper, and the cutting window narrows from four or five days to about two, so summer sowings need daily inspection once the buds are visible. Shade cloth over the middle of the day and a deep mulch both widen the window and improve the stems.
Water is the limiting factor. A summer crop wants an inch and a half (38 mm) a week, delivered in two soakings rather than daily sprinkles, and it wants it without fail during stem elongation. This is where hollow stems are made.
| Summer condition | Effect on the crop | What to do about it |
|---|---|---|
| Daytime highs 75 to 85F (24 to 29C) | Fast growth, slightly thinner stems | Water twice a week, cut two days earlier than you think |
| Daytime highs above 85F (29C) | Sharp flavor, two day cutting window | 30 percent shade cloth midday, mulch 2 inches (5 cm) deep |
| Dry spell during stem elongation | Hollow pithy stem centers | Soak to 8 inches (20 cm) rather than sprinkling daily |
| Long day length | Slightly faster run to flower | Shorten successional intervals to a fortnight |
| Heavy summer rain | Slug damage on stubs, downy mildew risk | Pull mulch back from stems, thin for airflow |
Autumn and the frosts: the best flavor of the year
The autumn crop is the one to plan properly, because kailan cut after a light frost is sweeter than at any other time of year. The plant converts starch to sugar as a cold response, and the difference is obvious on the plate. Make your last sowing about ten weeks before your expected first hard frost so that the main stem arrives before the weather closes in.
Mature plants take light frost without protection. Below about 25F (minus 4C) the stems start to suffer damage, so a row cover or low tunnel thrown over the last sowing extends useful cutting by several weeks in most climates. Cut in the middle of the day once the stems have thawed; a frozen stem bruises where you handle it and goes soft in storage.
Side shoots slow right down as temperatures fall, and a plant that gave a shoot every three days in summer may give one a week in late autumn. That is not a failure, it is simply the rate the plant can manage, and those late shoots are the sweetest thing in the garden.
- Count ten weeks back from first hard frost That is your last sowing date for a full main stem. Sowings later than this may still give baby stems worth cutting at 40 days if the autumn is mild.
- Row cover the last sowing once nights reach 32F (0C) Light frost improves flavor but a hard freeze below 25F (minus 4C) damages the stems. Row cover buys several extra weeks of cutting.
- Cut thawed, not frozen Wait until the middle of the day. Handling frozen stems bruises the tissue and they go soft within a day of coming indoors.
Keep a sowing and cutting log for one full season
The calendar above is a starting point, and it will be wrong for your garden by a week or two in one direction or the other. The way to correct it is a simple log kept through one season: sowing date, row position, final spacing, date of first cut, date the plant was pulled, and a one line verdict on the stems. Six entries over a season is enough to fix the timings for good.
Two numbers matter most. The first is days from sowing to first cut in your conditions, which tells you how far ahead to sow. The second is the number of days the cutting window stayed open, which tells you how often you need to walk the bed. Both change with the season, so record them for a spring, a summer and an autumn sowing rather than assuming one figure covers the year.
Record the position of each row as well as its date. Rows sown three weeks apart look identical for the first month, and losing track of which is which is how a whole sowing gets missed and goes to flower.