How to Make Compost Tea
There are almost as many ways to make compost tea as there are people making it. There is a growing number of people that are taking the art of making compost teas to an entirely new extreme. Let’s have a look at some different methods, brewers and ingredients people use in their compost teas.
Homemade compost or fresh vermicompost are ideal for making teas. Sometimes one might get caught without a supply on hand though. Purchased Compost will work to make a compost tea but it may be microbially inferior to our own compost.
Many people seek to add trace minerals to their teas for a power packed boost of microbes, nutrients and trace minerals. Some additions people like to add are:
- Kelp Meal -adds trace minerals
- Hydrolyzed Fish Fertilizer -stimulates growth of fungal hyphae
- Unsulphured Blackstrap Molasses – quickly grows bacteria. Adds trace minerals. Should be used only with caution, can grow microbes so quickly your tea may run out of oxygen.
- Alfalfa Leaf Powder – adds nitrogen and nitrogen cycling microbes.
- Purchased Compost Tea Catalyst – claims to feed and inoculate tea microbes
- Organic Liquid Humic Acid stimulates growth of fungi.
- Non-GMO Organic Whole Oats – promotes growth of fungi
There are dozens of compost/vermicompost tea recipes online. Regardless the recipe you choose the results will be dependent on the quality of the compost used. Please remember that nature is very forgiving and if your tea isn’t perfect it very unlikely to be damaging, it just may not be as good as it could be.
I’ll give here two recipes I’ve used with good results.
Recipe 1 (Lawns and green growth)
About 50 gallons (190 L) of water
4 gallons (16L) compost or worm casting
1 gallon (4 L) rolled or whole oats
2 cups (500 mL) alfalfa leaf (this will cause a lot of foam-may cause brewer to overflow)
2 cups (500 mL) of forest soil and/or 1/4 cup (60 mL) liquid humic acid.
Bubble water in your brewer for 12 hours to remove chlorine and maximize dissolved oxygen. Add liquid ingredients to the water 15 minutes before adding the dry ingredients in a Large Compost Tea Brewing Bag Hang the bag from the side of your brewer or follow the instructions for your brewer.
If you’re monitoring your tea with a microscope begin taking samples every 4 hours beginning at 24 hours. 36 hours of brewing is about where the magical maximum microbe density occurs. If you’re not using a microscope begin applying your tea between 32 and36 hours after beginning to brew.
About 50 gallons (190 L) of water
4 gallons (16 L) compost or casting
1/4 cup (60 mL) hydrolized fish fertilizer
1/2 cup (125 mL) kelp meal
2 cups (500 mL) forest soil
1 cup (250 mL) rolled or whole oats
Bubble water in your brewer for 12 hours to remove chlorine and maximize dissolved oxygen. Add liquid ingredients to the water 15 minutes before adding the dry ingredients in a Large Compost Tea Brewing Bag Hang the bag from the side of your brewer or follow the instructions for your brewer. Follow above brewing instructions.
Compost tea brewers can range from simple and cheap to complex and thousands of dollars.
This 5 Gallon Bucket Aerator is a good choice for those on a budget that only need smaller batches of tea. The above would still require you to buy a pump, tubing and bag separately or it also comes as a Kit with Brew Bag, Air Pump & Tubing (571GPH Air Pump) so you’re ready to brew asap.
This 10 Gallons Brewer uses a permeable membrane to provide small even sized bubbles and claims to provide better aeration. It does however come with a larger price tag as well. This one might be appropriate for the medical cannabis grower. See it in action below:
The 50 Gallon Compost Tea Kit known as a Bubble Snake is a budget friendly option for much larger batches of tea.
Using Your Tea
Regardless the method used compost or worm casting tea should really be applied on top of organic matter. For a lawn use a mulching blade to leave clippings on the lawn before applying your tea. In fall mulch some leaves right on the grass as well.
For a veggie garden add a heavy layer of mulch (leaves, straw, wood chips etc) then spray both foliage and mulch thoroughly. The microbes we are growing by making tea need organic matter to feed on. The goal is to create humus by decomposing our layers of mulch, grass clippings, leaves etc. Humus is nature’s ideal plant food. Using a quality compost tea in conjunction with organic matter will give you the best results possible.
The author has an affiliate relationship and/or another business connection to the providers of the products, that are contained within this article and may be compensated when you buy from a provider.