Giant Vegetable Growing and an up-date on the Leeks
13th Mar 2003
I was invited to have a look at Peter Glazebrook's garden, the giant vegetable grower, just after I had finished judging the North East Derbyshire District Association of the NVS show where Peter had won with a superb dish of Cedrico tomatoes. This proves that not only is he highly successful at growing vegetables to gigantic proportions, he is also equally at home growing them to the highest quality as well.
What did impress me on my visit there was the thinking that goes into growing the large onions that I dwelled on in last weeks issue. In order to try and find out a little more about how the onion develops, the root system in particular, Peter carried out an experiment which would proved to be highly successful. He grows his large onions in a large wooden type greenhouse that allows plenty of ventilation to get at the plants. They are grown in raised beds but as soon as I entered the house I saw one large single onion being grown very differently, just one onion on it's own.
What Peter had done was to utilise a clear plastic sheet that he happened to have lying around, when this was rolled into a cylinder it formed a growing area that was 30 inches in height and 26 inches in diameter. This was positioned on the concrete floor with a small wooden box formed on the bottom to support the side of the plastic. The plastic container was then filled with a John Inns type mixture which Peter made up himself. It took 6 barrowfuls to fill it and the outside of the clear plastic was then wrapped in black and white polythene, in this case with the black side facing outwards. This was to completely darken the growing medium just as if the onion was growing in a raised bed or in ordinary garden soil.
The Reason Why
The purpose of the exercise was to see and record the movements of the onions roots. After only one month they were already visibly touching the side of the plastic when the polythene was removed. By June time the roots were well down the container and the only little bit of feed that they had was towards the back end of the season when they were given some Chempak No8. Peter was so impressed by the results, including the size of the onion that he harvested, that he will grow a few more in the same vain this season. I visited Peter on the 31st August when the picture was taken, the onion was harvested a week or so later and it measured 28½ inches around and weighed 11½ pounds. (picture attached)
There is certainly food for thought here as every year the onion is going to be grown in perfectly clean nutritious compost. Yes it does take a lot of compost to fill the cylinder, but who knows, an even smaller container might suffice quite adequately. For instance I have grown onions for Chelsea up to 18 inches around in nothing more than 8 inches depth of soiless compost with the onions planted only 12 inches apart. If any of you are going to have a go at this sort of growing technique, then I would like to hear how you get on.
My blanch leeks are now in their 3½ pots and are ready for moving on into a 5inch pot or a one litre pot as they are called these days. Up to this stage, owing to a lot of other work requiring my attention at the same time, these were initially potted up into Levington M2 only. When the pot was removed I was pleased to see that there was a strong vigorous root system as white as snow, always a good sign that they have not been attacked by any disease. (picture attached). I have quite deliberately grown these leeks slightly cooler than normal and from this point on they will not be grown under any lights.
As soon as they are potted up they will be taken to my other greenhouse where they will have a minimum air temperature of 55°F. These will now have soil imported into mix, exactly the same as I do for my onions and will be as follows - 4 parts of Levington M3, 3 parts of soil and 1 part of Vermiculite, when making relatively small batches, 1 part for me is a 2 litre pot. Vermiculite is an inert material with no food value at all, this means that the mix is somewhat weaker and I therefore add 20 ml of Chempak potting base to 16 litres of compost. The soil that I use is available in 25 litre bags from Westland Horticulture, it's a specially selected sterilised and graded top soil, the best soil that I have yet used sold in bags.