Gadenin日本語Get the appThe shape of the year
Everything about stock follows from one constraint: it needs a run of cool weather while it is a young plant with a few true leaves, and it stops once nights are warm. The whole calendar is arranged around getting a plant of the right size into a cool spell, and then getting the flowers out of it before heat ends the show.
That gives two workable patterns. In a mild-winter garden, sow in late summer, grow small plants through autumn, overwinter them, and take a heavy flush from late winter into spring. In a cold-winter garden, sow under cover in late winter, plant out into cool spring soil several weeks before the last frost, and flower from mid spring into early summer. Direct sowing into the earliest workable spring soil is a simpler third option that gives slightly later flowers on very sturdy plants.
Pick the pattern that matches your winter rather than mixing them. The commonest failure is a spring sowing made too late, which produces a healthy leafy plant that never buds because the cold spell had already passed before it was big enough to respond.
| Stage | Cold winter garden | Mild winter garden | What you are watching for |
|---|---|---|---|
| Sow | Late winter, under cover, 55 to 65F (13 to 18C) | Late summer, direct or in trays | Even germination in seven to fourteen days |
| Sort doubles | At two leaves, on the bench | At two leaves, in the tray | Pale, large-leaved seedlings to keep |
| Pot up and grow cool | Bright bench near 50F (10C) | Cold frame or open ground | Short, thick stems, not drawn ones |
| Plant out | Several weeks before last frost | Early autumn, while soil is warm | Free draining soil, no waterlogging |
| Cold spell | Cool spring weather | Through winter | Four to six true leaves when it starts |
| Support and pinch | As plants reach six inches (15 cm) | Late winter, as growth restarts | Branching kinds only, never single spike types |
| Flowering | Mid spring to early summer | Late winter to mid spring | Cut when a third of the florets are open |
| Clear | When nights pass 65F (18C) | Before summer heat | Browning florets and no new buds |
Raising and planting
The sowing and early growing stage carries most of the work, and it is where the season is won or lost. Seed goes on the surface with the barest dusting over it, held cool and bright, and the seedlings are sorted into probable doubles and probable singles at the two-leaf stage using leaf color and size. Everything after that is straightforward.
Plant out young, before the roots circle the pot, into ground that drains sharply and has not carried brassicas in the last three or four years. Space branching kinds eight to twelve inches (20 to 30 cm) apart and single-spike kinds six to eight inches (15 to 20 cm). Cover new plantings with insect mesh if flea beetle is a regular problem, and leave it until the plants have six or eight true leaves.
- Prepare the ground before you sow Check drainage, lime towards a neutral pH, and work in grit if the soil is heavy. Do not add fresh manure. Rich ground gives leaves at the expense of spikes.
- Sow into cool conditions Surface sow with the thinnest covering, hold at 55 to 65F (13 to 18C), and move the seedlings into full light the moment they emerge.
- Sort the seedlings At the first true leaves, keep the pale, larger-leaved seedlings and discard the dark, narrow ones. A short chill of two or three days at 45 to 50F (7 to 10C) makes the difference obvious.
- Grow on cold and bright Aim for around 50F (10C) at night. Warmth at this stage produces soft, drawn plants that flop later and often fail to bud.
- Plant out early and shelter Go out several weeks before the last frost into free draining soil, in a sheltered spot near a door or a seat where the evening scent will reach you.
- Support and, on branching kinds only, pinch Get canes or netting in place while the plants are short. Pinch branching types at four or five true leaves for more spikes over a longer season.
Flowering and finishing
Once spikes are showing, feeding stops and cutting starts. Take stems in the early morning when a third of the florets are open, stripping any leaves that would sit below the water line. On branching kinds, cut every spent spike back to a leaf joint and expect side shoots and a second flush while the weather stays cool.
The end comes fast. When night temperatures settle above about 65F (18C) the florets shrink and brown, the scent thins, and no new buds set. That is the plant finished, not the plant sick. Clear the bed, remove the debris rather than composting anything that showed root distortion, and use the ground for something that wants heat.
Where you want seed, leave two or three single-flowered plants standing until the slim pods dry to pale brown. Fully double flowers do not set seed, so the seed you save comes from singles and will again produce a mixture the following year.
The record that makes next year easier
Three dates carry almost all the value: the day you sowed, the day the first spike opened, and the day the last spike browned. Subtracting the first from the second gives you the number of weeks stock needs in your garden, and that number is what lets you count backwards to a sowing date instead of guessing.
Add to that a note of which bed each batch went into, so the brassica rotation stays honest, and a line on where the plants stood and whether the evening scent actually reached the seat or the door. Position notes are the ones people never keep and always wish they had, because the difference between a good corner and a poor one is far larger than the difference between one sowing date and another.