How to Make Aerobic Compost tea
Gardeners already know compost is terrific stuff. But there's something even better than plain old compost, and that's aerobic compost tea. As the name implies, compost tea is made by steeping compost in water. It's used as either a foliar spray or a soil drench, depending on where your plant has problems.
Why go to the extra trouble of brewing, straining, and spraying a tea rather than just working compost into the soil? There are several reasons. First, compost tea makes the benefits of compost go farther. What's more, when sprayed on the leaves, compost tea helps suppress foliar diseases, increases the amount of nutrients available to the plant, and speeds the breakdown of toxins. Using compost tea has even been shown to increase the nutritional quality and improve the flavor of vegetables. If you've been applying compost to your soil only in the traditional way, you're missing out on a whole host of benefits. Some people have been able to stop all use of toxic sprays for blackspot and other diseases.
Supplies you will need
To brew aerobic compost tea, you'll need a pump, some air tubing, a gang valve, and three or four bubblers.
• An aquarium pump large enough to run three or four bubblers or air stones
• Several feet of tubing
• A gang valve
• Three or four bubblers with something to hold the bubblers down
• A stick to stir the mixture
• 8 cups of good quality compost without toxic spray (preferably from your own garden)
• one cup dried Unsulfured molasses (buy this at a feed store or Tractor Supply)
• one half cup of seaweed emulsion or fish emulsion
• Something to strain the tea, like an old pillowcase, tea towel, or a nylon stocking
• 2 5-gallon buckets
To brew aerobic compost tea, you will need a 5-gallon plastic bucket and a few aquarium supplies: a pump large enough to run three bubblers (also called air stones), several feet of air tubing, a gang valve (which distributes the air coming from the pump to the tubes going to the bubblers), and three or four bubblers. You'll also need a stick for stirring the mixture, some unsulfured molasses , some seaweed or fish emulsion, and an old pillowcase, tea towel, or nylon stocking for straining the tea. An extra bucket comes in handy for decanting the tea.
Don't try to make compost tea without the aeration equipment. If the tea is not aerated constantly, the organisms in it will quickly use up the oxygen, and the tea will start to stink and become anaerobic. An anaerobic tea can harm your plants.
Compost tea made using this bucket method needs to brew for two or three days and then be used immediately. Start the tea on Wednesday or Thursday, so it will be ready in time to apply it on the weekend.
Using rainwater is best. If you're on a well, you can use water straight from the spigot. But if you're using city water, run the bubblers in the water for about an hour first, before adding the other ingredients, to blow off any chlorine. Otherwise, the chlorine will kill all those beneficial organisms you've gone to the trouble of raising.
Cut a length of tubing and attach one end to the pump and the other to the gang valve. Cut three more lengths of tubing long enough to reach comfortably from the rim to the bottom of the bucket. Connect each one to a port on the gang valve and push a bubbler into the other end. Weight down the bubblers so they stay at the bottom of the bucket.
Fill the bucket about one eighth full of compost. Don't pack it in; the bubblers need loose compost to aerate properly.
Hang the gang valve on the lip of the bucket and bury the bubblers at the bottom, under the compost. Fill the bucket to within 3 inches of the rim with rainwater or well water, and start the pump.
Add the cup of dried molasses and half cup of seaweed or fish emulsion and stir the mixture with a stick.
Run the pump for about three days, stirring the bucket once a day. You will get bubbles at the top of the bucket, and the bucket may overflow a bit.
After three days, turn off the pump, remove the bubblers and rinse them off with a hose.
Strain the contents of the bucket into another bucket. You can use a large kitchen strainer to remove most of it, then strain through a piece of cloth to leave you with a liquid that can be sprayed on your plants or used as a soil drench.
The compost solids you strained out can be applied around the plants in your garden.
With a garden sprayer, spray your plants like you would with a foliar feed.
Within a week, your plants will be growing better than ever.
If you have questions, contact me. Or, go to this website. http://www.finegardening.com/how-to/articles/brewing-compost-tea.aspx
Please note that there is still some controversy about Aerobic Compost Tea. Further studies must be done to prove it's effectiveness. Stay tuned...
Jerry Haynes, President - Grayson County Master Gardeners