Brewing compost tea for cannabis is a great way to feed or supplement your crop of buds for healthier plants and better harvests. If you are unfamiliar with brewing compost tea, in a nut shell, you are taking organic materials that have nutrients like kelp meal, worm castings, alfalfa meal, unsulphated molasses, etc. Then putting them in dechlorinated water via a homemade “tea bag” while adding oxygen to unlock the nutrients & create healthy biological life in a living solution brew that you can water into your roots. Don’t forget the best seeds to use with your brew at Old School Breeders Association.

brewing compost tea for cannabis

8 easy DIY steps

  1. Ensure that the bucket has been scrubbed and sterilized. Adding one part chlorine bleach to ten parts water or the same ratio with bleach makes a good cleaning solution. Make sure that the bucket is thoroughly rinsed with lots of fresh water afterwards.
  2. Add about four US Gallons (3.785 L per Gal.) of water to the bucket. If the water has any chlorine in it, it can seriously harm the growth of the beneficial microbes you want to cultivate for application to your crop. Use R.O. (Reverse Osmosis) treated water, rain water, good quality well water or aerate your tap water with an air pump and airstones for 24 hours prior. Note that aeration will help some types of chlorine added at municipal treatment centers dissipate as a gas.
  3. Drop your airstone(s) into the water and then connect to air pump and switch on to aerate/bubble the water. Allow the water to warm up to at least 65°F or room temperature before proceeding with the next steps.
  4. In your clean cloth “tea bag” add 2-4 cups of earth worm castings or in VEG, Alfalfa Meal. Good quality earth worm castings should appear black and smell very rich and “earthy”. Next add 2-4 TBSP of dried kelp meal and micro-ionized ground rock phosphate to the bag. Tie-off the tea bag with a zap strap, so that all of the material will stay in the bag, and not fall out into the water. Make sure to leave lots of space for the materials in the bag to expand once it gets wet.
  5. Into the room temperature, aerated and de-chlorinated water, add your source of B-Vitamins and Carbohydrates, if they can be readily dissolved. Warm in hot water and whisking can help improve solubility and prevent clumping in the tea brewing solution.
  6. Drop your prepared tea bag into the bucket containing aerated and de-chlorinated water at room temperature.
  7. Ensure that constant and steady temperatures are maintained for the brew over the next 24-48 hours. DO NOT allow the water temperature to drop below 70°F or go above 80°F. A constant and steady temperature throughout the brewing process will result in superior quality teas.
  8. After 24-48 hours, the tea may be diluted and applied. If applying through a drip system or as a foliar spray, strain the raw tea before adding to your final volume of water for application. You may want to experiment with dilution rates, however one part tea to ten parts de-chlorinated fresh, pH adjusted water is a good place to start. When applying, you will not need to add any other fertilizers or additives. This tea does not replace your regular crop feeding program, it enhances it.

Stuff You Will Need for Brewing Compost Tea for Cannabis

  • 5 gallon bucket
  • De-chlorinated water, RO Filtered Water Preferred
  • Earth worm castings or Alfalfa Meal (More in VEG)
  • Dried kelp meal
  • Carbohydrate source (Hydroponic Carb Supplement, Unsulphated Molasses, etc)
  • Microbial Source (Optional, ie hydroponic microbial supplement)
  • Source of B Vitamins
  • Micro-Ionized Ground Rock Phosphate (Optional, More in BLOOM)
  • Aquarium air pump and airstones
  • Old pillow case or un-printed t-shirt and zap strap (to make the “tea bag”)