Gadenin日本語Get the appWhy the length of the season matters
From sowing to the last pick is typically twenty-six to thirty-five weeks, longer than any other common vegetable. The plant spends the first half building a frame and the second half filling buds, and the two halves want opposite things: plenty of nitrogen and water early, then restraint and cold later.
Almost every sprout failure comes from getting that switch wrong, or from making a decision at the wrong end of the season. Sowing three weeks late costs you sprout size in autumn. Feeding three weeks late costs you firmness. Neither can be corrected once it has happened, which is why it pays to think of the crop as a sequence rather than a set of jobs.
| Stage | Roughly when | What is being decided |
|---|---|---|
| Sowing | Late winter under cover, or spring outdoors | Whether the plant is big enough by autumn |
| Seedling in modules | Four to six weeks after sowing | Stem thickness, and whether it stretches |
| Planting out | Late spring to early summer | Anchorage, spacing, root fly protection |
| Frame building | Summer | Plant height, therefore the number of sprouts |
| Staking and last feed | Midsummer to late summer | Whether the sprouts blow |
| Bud formation | Early to mid autumn | Sprout firmness |
| Stopping the top (optional) | Mid autumn | Even crop versus long season |
| Picking | Late autumn through winter | Flavor, and how long the crop lasts |
Spring: sowing and raising the plants
Sow into modules once the soil or compost is above 54F (12C), which under cover means late winter for an early crop and outdoors means spring for the main crop. Two seeds a cell, half an inch (1 cm) deep, thinned to one at the first true leaf.
Grow them cool and bright for four to six weeks. The aim is a short, thick-stemmed plant with four or five true leaves, not a tall one. Harden off for a week before planting. Prepare the final bed at the same time so it has three weeks to settle: compost dug in, lime if the pH is below 6.5, and then leave it alone.
The whole crop hinges on being able to plant into settled, firm ground. If the bed is still occupied, prepare a different one rather than digging and planting on the same day.
Summer: planting out and building the frame
Plant out at 24 to 30 inches (60-75 cm) each way, deeper than the plant sat in its module, and tread the soil hard around each stem. Net immediately against cabbage root fly and butterflies. Water thoroughly two or three times over the first fortnight, then let the roots go down.
Through summer the plant is doing nothing but getting taller and wider, and this is when you feed it. A balanced feed three to four weeks after planting and again a month later. Keep the mesh on and check the growing point weekly for the first gray patches of mealy cabbage aphid. Stake when the plant reaches knee height, before it becomes top heavy, and draw soil up around the base.
| Job | Trigger | Consequence of skipping it |
|---|---|---|
| Tread the ground firm | At planting, and after every storm | Wind rock and blown sprouts |
| Net or mesh the bed | The day of planting | Root fly losses and caterpillar damage |
| Two balanced feeds | Three to four weeks after planting, then a month later | A short plant carrying few sprouts |
| Stake and earth up | When the plant reaches knee height | Leaning plants and open buds |
| Stop nitrogen | Late summer | Soft, loose sprouts in autumn |
Autumn: buds form and the decisions narrow
Sprouts begin as tiny buds in the leaf joints at the bottom of the stem and work upward. From this point the plant needs no more nitrogen, less water than in summer, and good air movement around the stem. Strip yellowing lower leaves as they turn and take the debris away.
This is when you decide about stopping the top. Once the lowest sprouts are marble sized, removing the growing point evens the crop up for a single large pick; leaving it on gives a longer, more staggered season. Re-firm the soil after gales, check the ties on the stakes, and open a sprout occasionally to see whether aphids have got inside the buds.
Winter: picking, and the end of the plant
Start picking when the lowest sprouts are firm to a squeeze, which is usually after the first frosts. Cold converts starch to sugar and genuinely improves the flavor, so the crop is better left standing in the garden than harvested early and stored. Work from the bottom of the stem upward, taking a few from each plant along the row.
Mature plants shrug off hard frost to around 14F (-10C). If a more severe freeze is coming, or you need the ground, cut whole stems and stand them in a cool shed, where they keep two to three weeks. When the sprouts start to loosen and push out shoots in late winter, the season is over: cut the top rosette to eat, pull the plants roots and all, and check those roots for clubroot before you compost anything.
Pull finished stems rather than leaving them standing. Old brassica stems carry mealy cabbage aphid and whitefly straight through to next season's plants.
The five dates worth recording
Sprouts give you one attempt a year and the feedback is slow, so a handful of dates in a notebook is worth more than anything else you can do for next year's crop.
Record these five: the sowing date, the planting out date, the date of the last nitrogen feed, the date the first sprout was genuinely firm, and the date of the first hard frost. Add one observation at the end of the season, which is how far up the stem the sprouts were good. If firm sprouts arrived well after the frosts, sow two weeks earlier next year. If the lower sprouts blew and the upper ones were fine, the ground or the staking was at fault. If the reverse, the last feed was too late. That is the entire diagnostic, and it only works if you wrote the dates down.