Kohlrabi Seeds – Brassica oleracea var. gongylodes

Under good conditions with soil temperatures between 50 and 70 degrees Fahrenheit, kohlrabi seeds typically sprout within 5 to 10 days. Germination depends on a combination of factors including soil temperature, moisture consistency, seed-to-soil contact, and your local climate, so results can vary. If your soil is on the cooler side, give it a few extra days before assuming a problem.

Kohlrabi grows well in soil with a pH between 6.0 and 6.8, which is slightly acidic to nearly neutral. Within this range, nutrients like calcium and boron are more readily available, which matters for brassicas that are prone to deficiencies in poorly buffered soil. A simple pH test before planting lets you amend with lime or sulfur if needed.

Kohlrabi container growing works well as long as you choose a pot that is at least 12 inches wide and 10 inches deep per plant. Use a well-draining potting mix and be prepared to water more frequently than in-ground plants, since containers dry out faster. A single large container with two or three plants spaced properly will give you a respectable harvest from a balcony or patio.

Kohlrabi harvest time is most reliable when the bulbs are between 2 and 3 inches in diameter, which usually falls around 45 to 60 days after sowing. At this size the flesh is tender and mild. Waiting until bulbs are larger than 3 to 4 inches often results in a fibrous, less pleasant texture, though some purple varieties hold their quality a little longer than green ones.

Kohlrabi is generally considered non-toxic to cats and dogs in small amounts, but it belongs to the brassica family, which can cause digestive upset such as gas or loose stools if eaten in quantity. It is always a good idea to keep curious pets out of the vegetable garden regardless, since repeated snacking on any plant material can cause problems. If your pet eats a large amount of kohlrabi and shows signs of distress, contact your veterinarian.

The swollen stem bulb is the most commonly eaten part, and it can be sliced raw into salads, roasted, steamed, or used like turnip in soups and stews. The leaves are also fully edible and can be used much like kale or collard greens, sauteed or added to soups. Younger leaves tend to be more tender and mild, while older leaves can be a bit tougher and more assertive in flavor.

Kohlrabi is a cool season vegetable and does not perform well when temperatures consistently exceed 80 degrees Fahrenheit. Heat causes the plant to bolt, meaning it sends up a flower stalk rather than forming a usable bulb, and it can make the existing bulb woody and bitter. In warm climates, the most successful approach is a very early spring planting or a fall crop timed so the bulk of growth happens in cooler weather.