Mamba (F1) Kale Seed

Scientific name

Brassica oleracea

Soil and water

Give kale rich, loose ground with plenty of organic matter and a pH somewhere between 6.0 and 7.5. Leaves stay tender and full-flavored when the soil never dries out for long.

Days to maturity

Counted from direct sowing. Transplanted kale is ready roughly two weeks sooner. For baby-leaf crops, follow the baby-leaf brassica notes.

Direct sowing

Sow any time from early spring until about three months ahead of your first fall frost. For bunching kale, drop 3–4 seeds in a spot every 12–18", 1/2" deep, with 18–36" between rows, and thin each spot to the best single plant.

Seeding rate

For bunching: about 1,000 seeds per 220 ft. of row; 1 oz. covers roughly 1,110 ft. and 1 lb. about 24,000 ft.

Spring transplants

Start 2 seeds per cell in 50- or 72-cell trays (thin to one), or 3–4 seeds per inch in open flats, 1/4" deep. Seed sprouts fastest with the mix above 75°F (24°C); after that, grow seedlings on near 60°F (16°C). They are ready to set out in 4–6 weeks, 12–18" apart in rows 18–36" apart. Kale grows best between 55 and 75°F (13–24°C), with 60–70°F ideal, though it still produces through warm summers.

Fall and winter crops

For fall, start seedlings in May and plant out in June or July; in places where hard freezes come early, sow on the early side. Where winters are mild and seldom dip below 32°F (0°C), plants can go out anytime from September through February.

Insect pests

Kale is bothered less than cabbage and other brassicas, but row cover laid at planting still keeps most pests off. Bt (Bacillus thuringiensis) handles cabbage worms and loopers.

Disease prevention

Prevention works best: rotate away from all brassicas for several years, use clean seed-starting mix and seedbeds, and keep tools and fields clean.

Harvest

Start picking individual leaves about two months after planting. Kale is very hardy and actually tastes sweeter after light fall frosts. Late-summer plantings can be carried through winter in a cold frame or hoop house, or in the open where winters are mild, and row cover stretches the picking season.

Sized seed

Seed is sorted to a uniform size for more even spacing in mechanical seeders and more even emergence, unless the description says it is unsized.

Transplants

Plan on about 6,400 plants per ounce of seed.

Packet

100 seeds.

Seeds per lb.

About 194,000 on average.