What plants should not be near kohlrabi?
Written by
Julia Anderson
Reviewed by
Prof. Martin Thorne, Ph.D.Kohlrabi grows well when neighbors are chosen wisely. Some plants compete for nutrients, attract the same pests, or inhibit the development of the bulb. Smart spacing may prevent that underground warfare and I learned that lesson after planting tomatoes which shaded the kohlrabi patch and resulted in skinny bulbs. Planting wisely may improve yield potential as well and help reduce the chance of diseases infesting the colonies.
Tomato Troubles
- Tomatoes consume 40% more nitrogen than kohlrabi
- Shade from vines reduces bulb expansion
- Shared susceptibility to cutworms
Strawberry Risks
- Both attract sap-sucking aphids
- Strawberry root weevils migrate to kohlrabi
- Fungal diseases spread between crops
There are options for smaller spaces. You can plant barrier crops such as garlic between kohlrabi and tomato; the strong odor acts as a pest deterrent. I have also used marigolds for this purpose; marigold roots secrete a natural chemical, alpha-terthienyl, that can help suppress nematodes. Vertical trellises can also be used for beans to minimize competition for nutrients in the soil.
Dill Allies
- Attracts parasitic wasps for cabbage worms
- Improves kohlrabi flavor intensity
- Requires 12-inch spacing
Onion Partners
- Repels carrot flies and aphids
- Shallow roots avoid bulb competition
- Plant 8 inches apart
It is essential to rotate brassicas every three years to reduce the chance of soil-borne diseases. My four-bed rotation (after kohlrabi, I went to legumes, then alliums) kept clubroot decimated for a decade. Be sure to test soil pH yearly; brassicas struggle to perform when the pH drops below 6.0, but a lime application in the fall usually takes care of this.
Read the full article: How to Grow Kohlrabi: Complete Beginner's Guide
