This plant is easy to grow from seed and will take around ten weeks at this time of year from sowing to harvesting. They are available in green (sometimes called white) or Purple. The Purple skinned varieties are usually hardier and better suited possibly for sowing now but I have found them to be slightly later in maturing.
Even though we are now in mid August, there is actually time to sow some more vegetables which will harvest prior to the onset of Winter. One vegetable that I think is particularly under utilised is the Kohl rabi, a member of the brassica family which is grown for its white fleshed turnip like swollen stem. The plant is easy to grow from seed and will take around ten weeks at this time of year from sowing to harvesting. They are available in green (sometimes called white) or Purple; because of the beautiful bloom that’s on the skin they always form a very important part of my Chelsea display.
The older varieties of Kohl rabi such as Green and Purple Vienna must not be grown too large as they will be tough and stringy, particularly if more than tennis ball size. However the newer hybrids such as the pale green Korist and the Purple skinned Kolibri can now be grown with good cultivation up to four inches across and still be tender and juicy. The Purple skinned varieties are usually hardier and better suited possibly for sowing now but I have found them to be slightly later in maturing.
To get the very best from each bulb, the top two thirds is the most tender, the nearer you get to the root plate, the tougher they become. To eat, simply peel away the outer skin, dice the flesh and either boil or steam for a few minutes, absolutely delicious on it”s own with some salt and pepper and a knob of butter!
As they are quick growing they don’t need a deep root run, indeed I have grown most of mine to maturity either in shallow raised beds or in pots. If you are going to grow them directly outside, sow a short row in an empty patch which has been raked over in your vegetable plot. Sow the seed shallowly and cover over with the rake compacting the seed well against the soil, moisten well if dry and then transplant to their permanent position when around two inches tall. As with all the brassica family, slugs love them so do take precautions to prevent them annihilating your crop. Also they are vulnerable to the Cabbage root fly and Club root, the latter can be alleviated by growing them above ground using the method below.
They will grow even better indoors and If you carry out the practice, like I do most of the time, of Table top Gardening, it gets a lot easier. The product that I use, which has been invaluable in my quest for Chelsea Gold Medals has been Link-a-Bord. This is basically a cavity walled panel or plank about an inch wide and 6 inches deep, which you can cut to any length and you fix it together to the shape you want with plastic corner pieces. You can go up a number of layers which are then held together with plastic dowels.
I have found that when growing Kohl Rabi or turnips, even lettuces and onions, I can get an excellent crop from just the one single layer sitting on top of my bench in the greenhouse. A metre square growing area is excellent, but even better is to cut the boards to a metre length and 18 inches wide. Two of these are more productive than one at a metre square as each growing plant has better light all around it. I am also convinced that the cavity in the boards have insulation properties which keeps the growing medium at a constant even temperature. Sow the seed inside your greenhouse or polytunnel in a small tray, transplant each seedling into a three inch pot when two inches tall. Fill the Link-a-Bord with Westlands Multipurpose compost which contains added John Innes and Perlite. Plant the pot grown seedlings in the medium at 6 inches apart, and water them on a regular basis. After 4 or 5 weeks give the plants a fortnightly liquid feed of Westland concentrated organic Tomato and Vegetable feed or Phostrogen.