Kohlrabi Growing Season
While each variety of kohlrabi may differ slightly in time to maturity and growing conditions, the following generally applies to all kohlrabi varieties.
Kohlrabi is a cool-weather vegetable and should be planted in the spring, three to four weeks before the last frost of the season. In warmer climates, you can also have a winter harvest if you plant your kohlrabi in the late summer. Kohlrabi grows best when planted in areas that get an average of six to eight hours of direct sunlight a day. You should sow your kohlrabi seeds ½ inch deep and 1 inch apart in rows spaced 18 to 24 inches apart. Kohlrabi does best in soil with a pH between 5.5 and 6.8.
On average, it takes 55 to 60 days for kohlrabi to reach maturity, and you will know that they are ready to harvest when the plant has a 12” spread and is 12” to 18” tall and when the fruit is 2” to 3”.