Kohlrabi is one of the weird looking vegetables in the garden but it can be grown rather easily if you follow a few simple guidelines listed below
When to Plant
You can start it indoors if you want a really early crop. Sow the first two weeks in March for a late April transplanting date outdoors. It will require a soil temperature of 21C to germinate and then a much cooler 12.5-15.5C growing on temperature to prevent leggy growth.
With direct sowing, you can put it into the ground from early May until July and it is often recommended that you sow several crops several weeks apart to get tender roots on an ongoing basis.
Where to Plant
In full sun in a soil where water and fertility is well-managed. No drought and no flooding.
How to Plant
Indoors- sow the seed approximately .6 cm deep. Each seed should be transplanted into its own small pot after it has 3 true leaves and grown on until transplanting outdoors.
Outdoors – sow seeds at one every 2-3 cm. When they start to grow and get a little crowded, thin to one plant every 10 cm. Harvest the small roots (eat them) and thin out as the plants get larger to one plant every 30 cm. apart.
Care & Maintenance
This is a very greedy feeder and will really benefit from adding a ton of compost to the soil where you intend to grow it. Feed every two weeks with a compost tea or fish emulsion to keep it growing strong.
It also likes to grow steadily (like cauliflower does) so avoid dry spells if possible by getting out the hose.
Actually, you’ll find if you do stress it, the roots will become woody and you won’t want to eat them. So water and feed this plant for decent edible crops or don’t bother.
Harvest all roots when they are smaller than a baseball (2 to 3 inches diameter) as the larger roots can get woody. And do harvest the roots before fall nights get too frosty; this plant doesn’t like cold temperatures in the fall.
You might see some flea beetles on kohlrabi but they are easily controlled by techniques listed on the organic controls pages.
(all numbers rounded out)
1/4 inch = .6 cm
1/2 inch = 1.3 cm
1 inch = 2.5 cm
6 inch = 15 cm
12 inch = 30 cm
18 inch = 45 cm
36 inch = 91 cm