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Vegetable Crop Calendars (A–C)Kohlrabi Planting Calendar
Kohlrabi is one of the quickest brassicas, which makes it a good filler crop, but a swollen stem that matures in heat turns woody and hot-tasting.
Key points
- Kohlrabi matures fast and suits both spring and fall.
- Cool weather keeps stems tender.
- Sow in small batches to stretch the harvest.
- Harvest at modest size before stems turn woody.
- Use row cover against flea beetles.
What makes kohlrabi different?
Kohlrabi is grown for a swollen stem that sits above the ground like a small bulb. It matures faster than cabbage or broccoli, often in a couple of months from seed, which lets you squeeze in a spring and a fall crop where seasons allow.
Fast growth is the key to quality. Stems that grow slowly or stall in heat become tough and fibrous.
Because kohlrabi grows so fast, it is a good crop for gaps in the garden. A short row planted where an early crop has been pulled can be harvested before the next crop needs the space.
When do you plant in spring?
Sow seed or set transplants a few weeks before the average last frost, once soil can be worked. Light frost is tolerated, though a cold spell early in the life of the plant can encourage bolting in some varieties. Check your state guide for lead times and bolt-resistant varieties.
Start sowing in small batches. A short row every couple of weeks stretches the harvest and reduces the risk that a heat wave spoils the whole crop.
Keep transplants moving without a check. A seedling that stalls in a small pot or in cold soil often produces a tough stem, so plant promptly and water well. Where springs warm quickly, use transplants rather than direct seeding, since a seedling that is already growing gets a head start on the heat. Where springs are long and cool, direct sowing is simple and works well.
When is the fall window?
Fall is often the better season. Count back from your first fall frost using days to maturity from your packet, and add a margin for slower growth as days shorten. Sow in mid to late summer so bulbs swell in cool weather.
For example, if your first frost normally arrives in late October, you would work backward from that date to your sowing time. That example only illustrates the arithmetic, so use your own frost data.
Fall kohlrabi tastes sweeter and stays tender longer than the spring crop in many places. Late sowings in cool weather make a good second harvest, and some varieties are bred specifically for fall and storage, so ask your extension office what local growers prefer. Check stems by gently squeezing, and harvest when they are firm and the skin is smooth. A stem that sounds hollow when tapped or that shows deep cracks has been held too long and is likely woody.
- Find your first fall frost date.
- Subtract days to maturity and a margin.
- Sow every couple of weeks early in the window.
- Cover plants if a hard freeze threatens.
When should you harvest?
Harvest when the stem reaches the size your variety description gives, and before it grows much larger. Most guides say oversized stems turn woody, though large storage types exist that are bred to stay tender at greater size.
Pull or cut plants at the base and trim the leaves. The leaves are edible too, much like collards.
For preserving kohlrabi, use tested procedures from the National Center for Home Food Preservation. Slugs hide under leaves and mulch near the swelling stem, so check the base of plants in the evening and remove hiding places.
What soil and water does kohlrabi want?
Fertile, well-drained soil with steady moisture grows the best stems. Dry spells cause tough, split or hollow stems. A soil test shows what the bed needs, and your extension office can interpret the results. Nutrient management rules vary by state.
Mulch keeps soil cool and holds water. Keep weeds down, since young plants compete poorly.
Thin plants to the spacing in your guide, since crowded plants compete for water and form small or distorted stems.
Which problems occur?
Flea beetles, cabbage worms, aphids and root maggots are common in this family. Floating row cover set at planting is a common barrier, and rotation reduces pest and disease buildup.
If a pesticide is ever considered, read the label, observe the pre-harvest interval, protect pollinators and check licensing rules. Ask your extension office what is active in your area.
Rotate to a different family for a few seasons after kohlrabi, and clear residue after harvest.
Sources and further reading
Last reviewed: November 2026. Educational information, ranges only. Confirm timing with your county extension office.