Artificial Lighting - Getting ready for Chelsea and the Summer Shows
23rd Feb 2005
Since I have had the benefit of being able to use the superb growing facilities at Bangor University to grow my vegetables for Chelsea, I have also been growing, initially, all my leeks and onions for the Summer shows there as well. However I do think that they actually grow on too quickly in the regular 16 hours of artificial lights that they are subjected too. I will therefore bring home both my onion and leeks so that I can look after them a little better in my own growing cabinet.
The leeks are now really romping away and are in need of potting on from their 24 cells per tray into individual 3½" inch pots. The compost this year will vary slightly from my normal use of the Levington professional M3, to Westlands Multipurpose compost with added John Innes and Perlite. What Westlands have actually done is to add a proportion of John Innes N°3 to their regular multipurpose peat based compost in order to give it a little bit more weight. My main reason for doing this is to try and find a compost that has the same capabilities as the one I make up using M3, but easier to get hold of. I very often get phone calls from growers who can not find a garden centre or any distributor that will sell them a couple of bags of the professional range such as F2S, M2 and M3.
The 3" inch pot will not be the plants final pot, they will need to be potted on at least once if not twice again before being planted out in their beds. As an experiment I am going to carry out two types of mixes, one will have nothing added to it, just the Westlands Multi Purpose straight from the bag. The other will be three parts of the above Multi Purpose to one part of Westlands Top Soil, straight from their bag and one part of medium grade Vermiculite. This is where I start to introduce the plants roots to soil and the next potting stages will have an increased ratio of soil to the multipurpose. This will give the compost a good buffer against any problems the plants might suffer from, such as perhaps being too dry or insufficient nutrients etc.
Last year, for the first time, I started to add Nutrimate to my potting mixes and I was really pleased with the results of the plants in their various potting stages. My onions in particular looked tremendous in their pots, the leaves were bolt upright, the colour was a lovely deep green and they just looked a picture of health. As I usually have a large number of plants to pot up, my quantity of compost in one go is quite a lot. I actually use a builders bucket for my measurement and they usually hold, more or less, 15 litres. To complete the above mix the total quantity would be 75 litres, which is about as much as I can turn over properly in my electric concrete mixer without it catching in the bottom.
The ratio recommended by Nutrimate to add to the potting up compost is 1lb, or 16 ounces, to 100 litres of compost. To my 75 litres of compost I will therefore add 10 ounces of Nutrimate. If you are mixing on a smaller scale and perhaps using a smaller measurement, then a builder's bucket full of compost would be mixed using a 3 litre pot as a measurement giving you a total of 15 litres to which you would add 2½ ounces of Nutrimate. If you are having a problem getting hold of Nutrimate you can order it direct by phoning 01772 641 181.
General Tips for both Leeks and Onions
I have always potted up all my leeks and onions in the same way for a number of years now. I generally pot up two sizes bigger than the original, in other words if I pot up from a three inch pot, I will use a 5" pot. The way I do it is to fill a 3" inch pot with the compost and sit it inside the 5" pot on top of sufficient compost to bring both rims nearly level. Centre the pot within the other one and start to fill around it, pushing the compost between the two pots until you are about the same level as the compost inside the 3" inch pot. Lift the 5" pot up and tap it on the bench, remove carefully the 3 inch pot and simply drop the leek or onion root ball into the moulded hole. Tap the pot on the bench once more and water well. I have noticed that the plants really like the more solid compost and simply romp away when given the correct growing environment. Finally use the plastic plant support clips to keep the plants bolt upright and prevent them from leaning over.
If you are using artificial lights I would switch them off totally now and remove any panels or covering that you have if they are growing inside a growing cabinet like mine would be. This is of course the shortest month, within a week we shall be in March, so give the plants plenty of air, open the roof lights wide on nice sunny days. In other words, start to gently harden the plants off for planting out in their beds, under covers, around mid April. If you are planting directly outside I would sooner pot the plants up and wait until early May when the weather should have settled down better and more accommodating towards the young plants.