Kohlrabi (Brassica oleracea gongylodes)belongs to the brassica family but produces a turnip-like bulb on its stem. Both the bulb and leaves are edible and it makes a great substitute for potatoes. We grow kohlrabi in Western Australia in the cooler months and start harvesting the bulbs around August. It can be grown throughout the warmer months however I find there are too many pests to combat with to make it worthwhile.
Best Months to Grow Kohlrabi in Perth
We find kohlrabi grows best in the cooler months, sow we like to sow our seeds in March and we are harvesting the last plants in September.
Soil Preparation for Growing Kohlrabi
Kohlrabi likes rich soil, so before planting out we add blood and bone, fresh compost, manure, organic slow release fertilser and a good layer of mulch.
Planting Methods for Kolhrabi
We prefer to sow the seeds into seed trays as we can sow them when the weather is still warmer (early march) and don’t need to be worried about plants bolting. It also allows us to continue using the garden bed space to grow until the plants are established. We have previously directly sown with great results.
Kohlrabi Plant Spacing
We like to plant our kohlrabi between 30-40cm apart. We used to plant them 20cm apart as recommend by most out there, but found the bulbs didn’t produce as well and with the larger spacing we found less pest damage.
Best Position for Kohlrabi
Kohlrabi grow best in full sun but can handle part shade.
Caring for Kohlrabi
After the initial garden bed feed, there isn’t much to do other than monitor for pest and diseases.
Kohlrabi Harvest Time
The harvest time for kohlrabi is 60-75 days.
Kohlrabi Frost Tolerances
Kohlrabi will tolerate mild frosts
Common Problems with Kohlrabi
We have found kohlrabi to fairly pest and disease free vegetable to grow. Other than the odd slug, snail or caterpillar which are normally just eating the leaves, not creating any problems. In 2022 we came across a new problems which was rats, which seem to love kohlrabi. We just control by trapping them.
Here are some other common problems you may come across but we have not yet.
Aphids are a sap sucking insect which are found on the underside of leaves or new shoots. The easiest method to control them is to squash them with your finger or use a high pressure jet to wash them off. If they persist you can spray them with a horticulture oil.
Stems haven’t swollen
Usually this is because the plant have taken to long to grow or the plants have become stressed.
Plants have bolted
This is when a plant goes prematurely to seed. This is caused when the plant becomes stress, normally from heat.
In the Kitchen
Both leaves and bulbs are edible. To prepare the bulb for eating the outside layer need to peel off revealing the white soft flesh. We also preserve are kohlrabi by blanching large cubes in hot water for about 3 minutes, then freezing it.
Some of the ways to use kohlrabi are steam the leaves, use the bulb or leaves in salad, use the peel, root and leaves to make a stock, roast the bulbs our favourite, in stews or soups and for chips