No, kohlrabi will not come back year after year in your garden. The kohlrabi plant life cycle spans two years in nature but you grow it as an annual. You plant, harvest, and start fresh each season. The kohlrabi annual or perennial question trips up many new gardeners.
I left a few kohlrabi plants in the ground one fall just to see what would happen. They survived winter in my zone 6 garden. Come spring, they sent up tall flower stalks instead of making new bulbs. Yellow flowers turned into seed pods over the next few months.
This happens because kohlrabi is a kohlrabi biennial at heart. Biennial plants live for two years. Year one they grow leaves and store energy. Year two they use that energy to flower and make seeds. Then they die after spreading the next batch of seeds.
Kohlrabi counts as a hardy biennial in the cabbage family. Wisconsin Extension lists it this way. Your plants can handle frost and cold temps without dying. But you harvest long before the plant finishes that full two year cycle. Most gardeners never see it flower since they pick bulbs early.
Kohlrabi bolting happens when your plant thinks it went through winter. Cold temps below 45°F (7°C) for too long trigger this shift. The plant switches from bulb growth to flower mode. A bolted plant makes tough bitter bulbs you do not want to eat.
You can prevent this problem by timing your planting right. Put spring crops in after the last hard frost passes. Start fall crops in late summer when temps stay mild. Avoid exposing young plants to cold snaps that might trick them into bolting early.
Some gardeners let plants overwinter to collect seeds. In my experience, this takes up garden space for many months. You also need to keep different brassica varieties far apart or they cross pollinate. Buying fresh seed each year works better for most home gardeners.
Treat kohlrabi as an annual crop for your best results. Plant it, harvest your bulbs in 45-60 days, and clear the bed. This keeps things simple for you. You get tasty kohlrabi without worrying about biennial timing.
Your garden space stays open for other crops this way. You can fit two or three kohlrabi plantings into one growing season. Each round gives you fresh bulbs in less than two months. That beats waiting a full year to see if your plant makes it through winter.
Read the full article: Growing Kohlrabi: Beginner-Friendly Guide
