Kossak F1

Family: Brassicaceae Brassica

Sweetly crisp and vividly tender, Kossak F1 forms a smooth, globe-like kohlrabi with a clean, pale green to creamy-white interior that tastes fresh and bright.

The flesh stays pleasantly fine-textured at maturity, making it a standout for quick, satisfying bites and for turning into silky purées and vibrant slaws. Grow Kossak F1 for a reliable 75-day harvest window and a garden-to-plate centerpiece that looks as good as it tastes.

Light: Full SunMaturity: 75 DaysHabit: Rosette

Planting schedules and alerts are optimized for Columbus (Zone 6b).

Crop Dates

Milestone	Date
Start Indoors	Mar 28th
Last Frost	Apr 25th
Transplant / Sow Outdoors	Apr 18th
Harvest Begins	Jul 2nd
Harvest Ends	Oct 16th

Crop Details

Trait	Value
Days to Maturity	75
Sun Requirements	Full Sun
Growth Habit	Rosette
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	75
Min Soil Temp (°F)	45
Min Night Temp (°F)	35
Harden Off (days)	6

Culinary Notes

Chef's Note

Kossak F1 stays tender without going woolly, so it holds a real bite whether raw in a slick slaw or briefly heated until it turns glossy and gentle. Its mild, sweet brassica edge makes it behave like a cross between radish and turnip—perfect for sharp acids and buttery finishes.

Best Uses

shaved or julienned slaw that stays crisp under tangy dressing
quick sauté/steam with a glossy butter-lemon finish
silky purée for a spoonable bed under roasted meats
radish-like snacking: raw rounds with salt and vinegar

Flavor Profile

sweet, snappy crunch mild brassica bite juicy, fine-grained tenderness bright, clean finish

Kitchen Pairings

lemon butter white vinegar mustard smoked salmon parmesan

Frequently Asked Questions

What pest or disease most commonly affects Brassica oleracea var. gongylodes (kohlrabi), and how can I treat it?

Look for cabbage worms/loopers and aphids; they leave holes in the leaves and stunt the kohlrabi swelling. Hand-pick caterpillars early, then spray Bacillus thuringiensis (Bt) on the foliage and reapply as directed every 5–7 days while larvae are active. If you see yellowing with a fuzzy gray/white growth, remove affected leaves immediately and improve airflow (spacing and thinning) to reduce fungal spread.

How often should I water kohlrabi during the main growing phase to keep the bulb tender?

During the 3–8 weeks when the kohlrabi is enlarging, water deeply about 1–2 times per week so the root zone stays evenly moist. Aim for soil moisture like a wrung-out sponge—water sooner if the top 1 inch dries, and avoid letting it swing dry-to-soggy because that commonly leads to woody, cracked bulbs.

How do I tell when kohlrabi is ready to harvest?

Harvest when the stem/bulb is firm and about 2–4 inches across (roughly 75 days from sowing for your crop), before it gets overgrown and tough. You should be able to gently feel the bulb under the soil—if it’s still soft or rapidly enlarging past your target size, wait a few days and check again. Cut the bulb at the base with a sharp knife and harvest in the cool part of the day to reduce wilting.