This is the first of what will be a year of monthly posts about different Asian greens.
Most Asian greens are chancy outdoors in the spring here in central Virginia, because our springs are short, escalating from cold weather to hot in not much time, and most Asian greens bolt as soon as it heats up. Senposai is the only one that is worthwhile for us to plant outdoors in spring. It grows quickly into a big plant producing large, round, mid-green leaves. Senposai is cold tolerant down to 12°F (-11°C) once hardened off, and also warm-tolerant (I won’t say heat-tolerant).
Senposai, which translates as Thousand Wonder Vegetable, is a cross between komatsuna and regular cabbage.
We start the seedlings in the greenhouse, sowing senposai February 7, the same date as our main spring cabbages. We spot out the seedlings into 4″ deep flats, 40 in a 12 x 24″ flat, as shown in the photo above. When the transplants reach a good size, we harden them off in the cold frame for two weeks, ready to plant out March 18 (at five to six weeks old).
We transplant senposai in 3 rows per 4 ft bed, with plants 18″ apart in the rows. Yes, they will grow into big plants.You could transplant at anywhere between 12″–18″ (30–45 cm) spacing, using the closer spacing if you will harvest often and prefer smaller leaves. When transplanting we use rowcover, but only keep it on the senposai until early April, when we take it away to use it on the newly planted broccoli instead.
Senposai is very fast growing. In the fall, senposai takes only 40 days to mature, but this early spring sowing takes 57 days. We can start harvesting senposai April 5 (almost as soon as we remove the rowcovers!) and continue till late May, when it starts bolting a week or two before the spring kale and collards.
Because senposai grows fast, it is very productive. It is usually harvested leaf by leaf,simply snapping off the bigger leaves. “8 for later” is our mantra to prevent over-harvesting of leafy greens – we encourage new people to count the leaves from the center out and take those in excess of 8 (or we might take fewer). After a while of counting, it becomes second nature to recognize what is a sustainable number of leaves to save for future harvests.
Senposai is tender, easy and quick to cook, much quicker than collards. It has a delicious sweet cabbagey flavor, and tender texture. It can be stir-fried, stir-braised, steamed and even eaten raw, by the fairly dedicated salad-lover.
Because it is fast-growing, senposai can be a good Plan B vegetable, to plant as a fast-growing substitute for cabbage or kale if something goes wrong with your original planting plans. We did this one spring when we got poor germination of cabbage.
Senposai also does well planted outdoors in the fall, and over the winter in our hoophouse, so it might reappear later in the year in this series of blogposts.
We buy seed from Fedco Seeds (who recommend it for okonamiyaki savory pancakes). “Customers buy it once because it looks absolutely stunning, then they buy it again because it is extremely delicious. Absurdly productive and easy to grow,” raves John Eisenstein of Port Royal, PA, in the Fedco catalog.