Brassicas
80days to harvest
7-14 daysdays to germinate
Z6–9USDA zones
Easydifficulty
F1 hybrid

Sowing

Direct sow after last frost, or start indoors 4-6 weeks before transplanting

Cultivation

Sun
Full sun to partial shade (4-6+ hours)
Water
Regular, consistent moisture
Soil
Well-drained, fertile soil, slightly acidic to neutral
Spacing
8-10 inches
Height
10-24 inches
Season
Warm season annual

Appearance & flavour

Colour
White or pale cream
Size
8"
Shape
Round, globe-shaped
Flavour
Sweet, tender, and delicious with a mild, pleasant flavor profile.

In the kitchen

Roasting, boiling, steaming, raw in salads, soups, stews

Pests, disease & resistance

Pests
Cabbage moths, flea beetles, root maggots
Diseases
Clubroot, black rot, bacterial leaf spot

Planting calendar by USDA zone

ZoneStart indoorsTransplantDirect sowHarvest
1April – MayJune – JulyJune – JulyAugust – September
2April – MayJune – JulyMay – JulyAugust – September
3March – AprilMay – JuneMay – JuneJuly – October
4March – AprilMay – JuneApril – JuneJuly – October
5February – MarchApril – MayApril – MayJuly – November
6February – MarchApril – MayApril – MayJune – November
7February – MarchApril – MayMarch – MayJune – November
8January – FebruaryMarch – AprilMarch – AprilMay – December
9JanuaryFebruary – MarchFebruary – MarchApril – December
10JanuaryFebruary – MarchJanuary – MarchApril – December
11JanuaryJanuary – FebruaryJanuary – FebruaryMarch – December
12JanuaryJanuary – FebruaryJanuary – FebruaryMarch – December
13JanuaryJanuary – FebruaryJanuary – FebruaryMarch – December

Companion planting

8 beneficial pairings indexed for this variety, 3 to avoid.

MarigoldsRepels cabbage moths and other harmful insects with strong scent
OnionsRepels cabbage worms, aphids, and flea beetles with sulfur compounds
LettuceBenefits from shade provided by larger brassica leaves, efficient space use
SpinachGrows well in partial shade of brassicas and doesn't compete for nutrients
CeleryRepels cabbage white butterflies and provides natural pest deterrent
CarrotsLoosens soil for brassica roots and doesn't compete for same nutrients
DillAttracts beneficial insects like parasitic wasps that control cabbage worms and aphids
NasturtiumsActs as trap crop for flea beetles and aphids, draws pests away from brassicas

Avoid

StrawberriesCompetes for nutrients and can stunt brassica growth
TomatoesInhibits brassica growth and both plants compete for similar nutrients
Pole beansCan shade out brassicas and compete for nitrogen in soil

Nutrition (per 100 g)

Calories (per 100 g)
31
Protein (g)
2.57
Fat (g)
0.34
Carbohydrate (g)
6.27
Fibre (g)
2.4
Vitamin A (µg)
8
Vitamin C (mg)
91.3
Vitamin E (mg)
0.15
Vitamin K (µg)
102
Vitamin B6 (mg)
0.191
Folate (µg)
65
Calcium (mg)
46
Iron (mg)
0.69
Magnesium (mg)
21
Phosphorus (mg)
67
Potassium (mg)
303
Zinc (mg)
0.42
Selenium (µg)
1.6

Where to buy seed and equipment

Some links are affiliate links. If you buy through them we may earn a commission at no extra cost to you.

Growing it? There is a full cultivation guide at the brassicas growing guide.

Cultivar facts compiled from public horticultural references including USDA GRIN and NC State Extension. Descriptions are original to this catalogue.

DarkGrow forum

Grown Kossak?

Post a crop report — day counts, reservoir readings, what worked. Variety-specific logs are the most useful thing on the forum.

Similar varieties

Other brassicas with a comparable time to harvest, so a season that suits Kossak suits these too.

Browse all 79 brassicas