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In the garden we look to make the most of our resources. Nettles and comfrey are there for the taking and everyone says they make great free fertilizer so we thought we would see how easy, how practical and how productive compost tea might be to make and to put on the garden. We mainly used Joy Larkcom’s book “Grow your own vegetables” for advice. And the RHS book “Science and the Garden” has got a lot of the science behind how it all works. Both of the books are available from PLANT gardening library.

Comfrey is a deep-rooted hardy perennial plant that thrives in light shade. It works as a groundcover and the bees love the flowers. It is rich in potash, with useful amounts of nitrogen and phosphate. Nettles grow in any fertile soil. Moths and butterflies are drawn to the nettle patch but people need to take a bit of care! Nettles are a rich source of nitrogen. Although we limited ourselves to just nettles and comfrey we’ve since heard that a couple of garden volunteers have been experimenting with seaweed tea.

We use two methods to extract the goodness. The easier and smellier is to fill a bucket with chopped up leaves, flowers and stems. Try not to get seed heads in the mix. Then fill with water, preferably rainwater. You’ll need some sort of weight to keep the vegetation under the water. Cover to stop any insects getting in and label the buckets with the date and the type of plant. Then wait four weeks for the magic to happen. Strain the remains (we put them on the compost) and the liquid can be stored in a closed container in a dark cool place. We’ve just been putting it on to the garden beds. Advice on applications is a bit hit or miss, so we’ve been diluting it about 1:10 with fresh water and using watering cans to get the tea to the plants.

If the smell is too much for you, you can apparently use an oxygenator from a fish tank to bubble air through the mixture but we haven’t tried that. And of course this is only a small scale trial so if you want to go big you can replace the buckets with a water barrel! One idea I like for a larger scale is to put the vegetation in an old pillow case, that way you don’t have to strain it and the rotting matter does not clog the tap of your barrel.

We’re also trying a water free method, packing chopped leaves and stems of the nettles into a vessel with a tap at the base. Then weighing the material down to press out the juices that should start to form after 10 days. Already it’s clear that this method would be better done on young spring growth, rather than summer but we are starting to get some liquid.

We are doing our experiment in the shade to keep things neat and tidy but decomposition might be faster in the sun.

The comfrey tea is going on the tomatoes and courgettes. It’s good for plants grown for fruit and flowers. The nettle tea is going on the brassicas where we want to encourage leafy growth. It’s important not to use the nettle tea on peas and beans as they fix nitrogen from the air and this is one instance where you can actually have too much of a good thing.

We’ll let you know how we get but if you’ve made compost tea and have any thoughts to share on the best way to make or use it, do get in touch and we can spread the knowledge.


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