Gadenin日本語Get the appThe shape of the mibuna year
Most gardeners meet mibuna as a spring salad leaf and are quietly disappointed, because the spring crop is the worst one it offers. Treated as an autumn and winter crop it is one of the most productive things in the garden: sown once as the summer heat breaks, a short row will give repeated cuts from mid autumn until the flower stems come up the following spring, through weather that has killed everything else in the bed.
The year therefore has four distinct phases, and knowing which one you are in tells you what to do without any dates at all. That matters because mibuna responds to soil temperature and day length rather than the calendar, and the same advice has to work in either hemisphere.
| Phase | Trigger to watch | Main jobs |
|---|---|---|
| Establishment | Summer heat breaks; soil under 75F (24C) | Sow, thin twice, mesh against flea beetle |
| Bulking | Nights turning cool, first light frosts | Feed after every cut, strip bottom leaves |
| Holding | Hard frosts, growth visibly stalled | Harvest sparingly, cover, stop feeding |
| Bolting | Days lengthening past about 13 hours | Last cuts, then pick flower shoots, clear the bed |
Establishment and bulking: the season that matters
Start sowing once the worst summer heat has passed and the soil has dropped below about 75F (24C), and keep sowing every two to three weeks until roughly eight weeks before your ground normally freezes hard. Get the mesh on from day one against flea beetle, thin in two passes, and get the plants out to their final spacing before the leaves start overlapping.
As the nights cool the plants come into their own. This is when you take the first proper cuts, at an inch and a half to two inches (4 to 5 cm) above the soil, and feed at half strength within two days of each one. Growth is fast enough at this stage that a plant can be back to cutting size in ten days. Keep stripping the flat bottom leaves that lie on the soil, and keep the crowns dry by watering the ground in the morning rather than the plant in the evening.
- Sow into a bed you have already fed Work a bucket of compost per square yard (square meter) into the top six inches (15 cm) before sowing. Cut-and-come-again crops export nutrients fast and you will not get another chance to improve the soil underneath them.
- Mesh on the day you sow Fine insect mesh over hoops with the edges buried, put on before the seedlings emerge. Going on after you see shot-holes just traps the beetles inside with the crop.
- Take the first cut earlier than feels necessary Cutting at five or six inches (13 to 15 cm) rather than waiting for full size gets the plant into its cut-and-regrow rhythm sooner and gets you more cuts before the cold slows everything down.
Holding through winter
Mibuna is properly cold hardy. Established plants take frost without protection, and the flavor improves markedly after two or three hard frosts as the plant holds sugars against the cold. Winter mibuna is sweeter and rounder than the same plant in autumn, and that is the main reward for having sown in good time.
What changes in deep cold is that the plant more or less stops growing. Regrowth after a cut can take a month rather than a week, so harvest becomes a matter of taking a few leaves from many plants rather than shearing whole rows. Stop feeding entirely: nothing is being taken up, and soft growth in cold wet conditions is exactly what rots. A cloche or low tunnel does not make it grow much faster but it keeps the leaves clean and undamaged, which is worth the trouble. Ventilate on mild days so the crowns dry out.
Cover is for holding a crop you already grew, not for growing one. A plant that goes into hard cold at eight inches (20 cm) will feed you all winter; one that goes in at three inches (8 cm) will simply sit there until the light returns.
Spring, summer and the gap
As the light returns the overwintered plants surge, and that flush is the last good leaf you will get from them. Take it promptly, because the thickening crown and narrow upright new leaves that follow mean the flower stem is a few weeks away. After that, harvest the shoots while the buds are tight, then clear the bed and use the ground for a summer crop.
A late-winter sowing is worth making if you want spring leaves, but sow it densely and shear it as baby leaf at four inches (10 cm) rather than trying to grow full plants. Through high summer, do not sow at all. Seed germinates and then bolts at a few inches tall, and the leaves that do form are unpleasantly harsh. Grow something that likes heat in that ground and come back to mibuna when the nights start cooling.
The records that make next year easier
Four dates are worth keeping, and together they replace every general rule with something specific to your garden. The date summer heat broke and you made your first sowing. The date of first emergence, so you know how your soil is behaving. The date growth visibly stalled in the cold, which sets how late your last useful sowing can be. And the date the first plant showed a flower stem in spring, which tells you exactly how long the crop lasts for you. Note where in the garden each batch grew as well, so you can move brassicas around on a three-year rotation without having to remember it.