Go Organic: Liquid feed your tomatoes will relishBy James Ashford
June 10, 2011
There was a happy sight in my greenhouse at the weekend; the first tomato of the season.
It’s still very green and I’ll probably have to wait a week or two for it to ripen – but it’s a sign that summer is here.
Tomatoes can be productive plants, especially of you have a greenhouse, but they do need feeding if you want to get a really good crop.
General-purpose fertilisers tend to be high in nitrogen which is great for producing lots of green leaves, but you don’t need lots of leaves on your tomato plants. For a good crop you need to boost the potassium levels in the soil.
You can buy organic tomato feed at most good garden centres but you can also make your own. Not only is it a lot cheaper but it also saves on the fuel used to produce and transport the commercial product.
Ordinary garden compost is great for adding bulk to the soil but it tends to be quite low in nutrients. Normally this is a good thing in the organic garden. Plants that are grown in a very rich soil tend to be lush and sappy, ripe for pest and disease. Plants grown more slowly tend to be tougher and better able to withstand attack.
However, greenhouse tomatoes are grown in a relatively small amount of soil and the extra heat means they grow fast. To fuel them you need to provide a really rich growing environment.
Organic growers have developed a liquid feed made from comfrey, which is rich in potassium and ideal for tomatoes.
Comfrey leaves are stuffed into a piece of tubing – a drainpipe is ideal – that is held upright. A heavy weight, narrow enough to slide down the tube, is put on top of the leaves to compress them, and a jam jar or pot is placed at the bottom to catch the liquid as it is pressed out.
This potassium-rich liquid is diluted about 1:20 with water and should be applied to the tomato plants once a week throughout the season.