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 September. 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
Sow in March to May
Kohlrabi likes rich soil, so before planting out we add blood and bone, fresh compost, pelletised chicken manure to the garden bed.
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.
The more sun the better
After the initial feed of blood and bone, we liquid feed weekly. As the weather cools off we feed fortnightly. Once the bulb is starting to appear we stop feeding.
70 -90 days
Will tolerate mild frosts
- Caterpillar – To control:
- Pick caterpillars off by hand, inspect leaves regularly for eggs and squish the eggs. For army worm, check on plants at night
- A bacteria called Bacillus thuringiensis also known as dipel, available from your local garden supplier
- Soap spray – this doesn’t kill caterpillars but I have found it stops the moths and butterflies from laying its eggs on the leaves
- White fly – To control:
- White oil
- Soap Spray
- Spray with water – you will need to do this for several days in row as they hate being disturbed
- Vacuum cleaner – use you vacuum cleaner on a low setting and suck them up. Remove them from your vacuum cleaner and place in a black bag in the sun
- Aphids – To control:
- White Oil
- Soap Spray
- Spray with water
- Slugs and Snail – To control
- Go out a night with a torch and remove slugs and snails. We try to do this weekly
- Beer/yeast trap
- Place a piece of board on the ground; slugs love to live under this. Remove slugs from the board and kill
- Place a black pot upside down in the garden in a cool moist spot. During the day snail and slug will go to this pot. Remove any snails from the pot.
- Root Knot Nematodes – this causes stunted growth and poor plant health, unfortunately if you have root knot nematodes there isn’t much you can do for crop, but you can help prevent it for the future by:
- Encouraging soil life, building a healthy soil will enable the beneficial nematodes to attack the pest nematodes. Here are 6 ways to boost your soil quality
- Sow mustard as green manure
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
- for chips