Kohlrabi Planting Guide

Kohlrabi Planting Guide

View/Download PDF

Shop for Kohlrabi Seeds

Kohlrabi probably originated in coastal Western Europe and is grown for its leaves, but more so for its large, bulb-like stem that develops just above the surface of the soil. We like to compare kohlrabi bulbs to turnips, but they grow above the soil, not below it. In the same family as cabbage and broccoli, Kohlrabi prefers cool temperatures and moist soils.  Plants are fast growing, reach about 2 feet tall, are ready in 50-60 days. They taste like turnips with a texture similar to water chestnuts, and can be sliced and eaten raw, steamed or sautéed.


Kohlrabi prefers sandy soil that is rich in organic matter, well drained, and not too heavy.  They also need full sun exposure.  Before planting, incorporate 2-3 inches of well composted organic matter and 1-2 lbs of all-purpose fertilizer (we recommend “That’s All it Takes” complete fertilizer) per 100 square feet and work them into the soil to a depth of 4-6 inches.  Heavy, claybased soils must be amended with compost and organic matter to encourage and allow good root development.  If you have heavy soil, we recommend 4-6 inches of organic matter and 50 lbs of Utelite or Zeolite per 200 square feet added to the soil each fall for multiple years to increase drainage and nutrient availability.  Over time, you can create a better growing environment for your garden plants to thrive in and produce.  Please see our information sheet “Preparing your Soil” for more detailed info on soil preparation before planting a garden


Kohlrabi can be planted from seed or transplant. Like other Cole crops, kohlrabi tends to bolt when temperatures are high so plant in cool weather (March & April). Young plants can resist a light frost but not a hard freeze, but don’t wait until May. Heat can stunt the early development of your crop. When planting starts, place plants 4-6 inches apart in the row, with 2 feet between rows. For best results, water immediately after transplanting with Kangaroots rooting solution and again for the first 2-3 waterings. This will prevent transplant shock and give your transplants the best possible opportunity to thrive. When planting seed, lightly sprinkle seeds every inch or so and cover them with about ¼ - ½  inch of loose light soil, and tamp them down gently  As seedlings emerge, thin sprouts to 3-4 inches apart when plants have 3-4 true leaves. 


Anderson’s has a few great varieties of Kohlrabi to choose from: Purple Vienna: Plants are 8-10 inches tall with purplish-green stem and leaf. Bulbs are 2 inches in diameter and flattened globe in shape with reddish-purple skin and white flesh. Should be used when about 2 inches in diameter, otherwise its texture becomes woody. White Vienna: A standard variety. Leaves 8-10 inches long with slender petioles. Bulbs are very light green, round, and 2-3 inches in diameter at prime state for table, but can become considerably larger. 


Water Kohlrabi deeply and frequently while trying to maintain even soil moisture, especially since they have a fairly shallow root system. Kohlrabi needs consistent watering for high quality and quantity production. Water stress during growth and bud production will result in loss of flavor, woody texture, and poor quality. Use a soaker hose for uniform water distribution and water lightly every 5-7 days to maintain soil moisture during these essential growth stages. A light compost mulch can help as well if daytime temperatures start to climb over 80 degrees.


Apply ½ cup per 10 feet of row of “That’s All it Takes” complete fertilizer or Happy Frog Organic Tomato & Vegetable Food 4 weeks after transplanting or thinning to encourage vigorous plant growth.  A second application of fertilizer may not be necessary, as  kohlrabi develops very quickly. If needed, fertilize again 4 weeks after the last application. Place the fertilizer evenly just to the side of the plants in the row and work it lightly into the soil before watering. Make sure to water it in! We also recommend treating your kohlrabi seed or plants with beneficial microbes and mycorrhizae (Kangaroots or Myke).  These added helpers bring nutrients and water directly to the plants that host them, making them stronger, more resistant to insects and diseases, and more drought tolerant. 


Keep weeds to a minimum with diligence and persistence. Treflan and Corn Gluten weed preventative herbicides are very effective ways to stop weeds before they start, saving you hours and hours of weeding, and they are completely safe to use on Kohlrabi. Be sure to control weeds when they are small to ensure damage is not done to tender, small root systems when weeds are removed. Practice crop rotations to discourage pest problems. Kohlrabi is subject to aphids, cabbage loopers, imported cabbage worms, and cabbage root maggots.  Row covers will help protect plants from all of these pests.  All of the caterpillars may also be controlled using Bacillus thuringiensis (B.T.), spinosad, or pyrethrin. We prefer Spinosad (since it is bacterial, it has no effect on people or pets), which is most effective when sprayed early or late in the day. Aphids love kohlrabi, so watch for them closely.  They can be controlled with an insecticide like Fertilome Broad Spectrum Insecticide or Ferti-lome organic Triple Action.


Kohlrabi can be harvested when stems reach 2-3 inches in diameter. In larger stems the flavor can become hot and the texture tough and woody.  Kohlrabi can be stored 2-3 weeks at 35 degrees.   Like beets and turnips, if stored in sand or peat moss, you can extend storage time by a month or two.

Back to blog

Leave a comment