Compost tea has become an increasingly popular organic nutrient solution for growing healthy cannabis plants. Made by steeping quality compost in water, compost teas provide a concentrated dose of beneficial microbes and nutrients that can enhance soil health, plant growth, yield, and terpene development when applied properly.
This complete guide will cover everything you need to know about making and using compost teas for weed, including:
- Benefits of Compost Tea for Cannabis Plants
- Choosing the Right Compost
- Brewing Methods
- Compost Tea Recipes
- How to Apply and Use Compost Tea
- Timing and Frequency
- Troubleshooting Common Issues
- Comparison to Synthetic Fertilizers
Whether you’re new to compost teas or looking to get the most out of them for your weed garden, this guide will help you leverage the power of compost tea to unlock the full potential of your plants.
Benefits of Compost Tea for Cannabis Plants
Compost tea offers a wide range of benefits that can improve the health, vigor, and quality of cannabis plants when applied as a soil drench or foliar spray. Here are some of the top reasons to use compost tea for weed:
- Provides a diversity of beneficial microbes – The steeping process extracts beneficial bacteria, fungi, protozoa, and nematodes from quality compost. These microbes colonize plant roots and surrounding soil, enhancing nutrient absorption and protecting against disease.
- Supplies a broad spectrum of soluble nutrients – In addition to microbes, compost tea contains many soluble macronutrients (NPK) and micronutrients that are immediately available for plant uptake.
- Improves soil structure and nutrient retention– The microbes in compost tea produce compounds that improve soil aggregation and water retention. Healthier soil holds onto nutrients better.
- Enhances terpene and cannabinoid production – Added microbes and nutrients boost plant metabolism and energy, which can increase terpene and resin gland production.
- Fosters vigorous root growth – Microbe-rich compost tea stimulates root branching and colonization, supporting faster growth and bigger yields.
- Protects against pests and diseases – Beneficial microbes form symbiotic relationships with plant roots that prevent pathogens like fungi, bacteria, and nematodes from infecting the plant.
The bottom line is that regularly applying compost tea gives your cannabis plants and soil an extra nutritional boost that translates into visible improvements in growth, yield, potency, and aroma. Now let’s look at choosing the right compost.
Choosing the Right Compost
Not all compost is created equal when it comes to brewing compost tea. The starting compost is arguably the most important factor in producing a high-quality tea. Here’s what to look for:
- A diverse mix of feedstocks – The compost should contain a variety of materials like plant trimmings, vegetable waste, manure, and other amendments. Diversity promotes more microbial life.
- Well-aged – Give compost at least 6 months to fully mature and stabilize. Fresher compost can overly oxygenate the tea.
- No pesticide residues – Ensure the compost is made from organic waste to avoid chemical contamination.
- High fungal content – Visible mycelium strands indicate healthy fungal populations that benefit cannabis.
- Earthy aroma – Mature compost has an earthy, humus-like smell, not an ammonia odor.
- Fine texture – Compost used for tea should have a crumbly texture and break down easily in water.
- pH 6.5-8 – Test that the compost pH is slightly acidic to neutral to brew a balanced microbial tea.
Quality compost contains a robust community of microorganisms and a complete nutritional profile. This diversity and abundance gets extracted into the finished tea. Using mediocre compost produces mediocre results. Investing in high-grade organic compost pays dividends in the vitality of your plants.
Brewing Methods
Creating compost tea is a simple process, but some methods produce better results than others. There are two main ways to brew compost tea:
Passively Aerated Tea
This involves steeping compost in water for 1-2 weeks with occasional stirring as the only aeration. Without added oxygen, this technique extracts some microbes and nutrients but the diversity and concentration are lower.
Process:
- Add compost to dechlorinated water at a ratio of about 1:10.
- Stir or agitate the mixture daily and keep it in the dark.
- After 7-14 days, filter the finished tea through a fine mesh screen, cheesecloth, or burlap.
- Use the tea within a few hours of filtering.
The lack of consistent aeration limits microbial multiplication, so passively aerated tea has fewer benefits than actively aerated methods. But it’s simple and requires no special equipment.
Actively Aerated Tea
Actively aerating the tea solution dramatically enhances microbial growth and extraction. This is achieved by continuously bubbling air through the mixture using an aquarium pump and air stone.
Process:
- Add compost to non-chlorinated water at a 1:10 ratio in a bucket or tub.
- Use an air pump to oxygenate the tea for 24-36 hours. Keep temperature around 70°F.
- Screen the finished tea through a fine filter to remove large particles before applying.
- Use the tea quickly within a few hours for maximum potency.
Actively aerated tea supports 100-1000 times higher microbial populations and concentration of nutrients compared to passive methods. The extra oxygen fuels microbial blooms that produce more plant-beneficial compounds. The increased microbial density also improves soil colonization after application.
Compost Tea Recipes
When brewing actively aerated compost tea, additional amendments can be added to enrich the diversity of microbes and nutrients in the finished product:
Basic Aerated Compost Tea
- 5 gallons dechlorinated water
- 1 cup quality compost
- 1 tsp unsulfured blackstrap molasses
- Air stone and pump for 24-36 hours
Flowering Enhancer Tea
- 5 gallons dechlorinated water
- 1 cup compost
- 1 tsp molasses
- 1 tbsp kelp meal
- 1 tbsp langbeinite
- 1 tsp humic acid
- Aerate for 24-36 hours
Root Growth Tea
- 5 gallons dechlorinated water
- 1 cup compost
- 1 tsp molasses
- 1 tbsp fish hydrolysate
- 1 tbsp humic acid
- Aerate for 24-36 hours
Pest/Disease Prevention Tea
- 5 gallons dechlorinated water
- 1 cup compost
- 1 tsp molasses
- 1 tsp neem meal
- 1 tbsp garlic powder
- 1 tbsp horsetail herb
- Aerate for 24-36 hours
These amendments provide complementary nutrients and compounds that amplify the benefits of the base compost tea. Molasses feeds microbes, kelp supplies micronutrients, fish hydrolysate adds amino acids, and so on. Get creative with different additives like alfalfa, rock dust, insect frass, etc.
How to Apply and Use Compost Tea
Compost teas can be applied directly to soil as a drench or sprayed onto plant leaves and stems. Here are some tips for maximizing results:
- As a soil drench – Water plants thoroughly, then apply 1-2 cups of finished tea directly to the root zone. This inoculates soil biology.
- As a foliar spray – Mist diluted tea onto leaves until just before runoff. Spray in evenings to avoid leaf burn. Boosts nutrient absorption.
- Target the root zone – Focus applications around stem and root areas, not just on top of soil. Direct contact benefits microbes.
- Avoid hot sun – Don’t apply teas in direct sun or hot weather which can scorch leaves if liquid dries quickly.
- Use within 6 hours – Fresh tea is up to 90% more effective than storing for later use. Microbes start dying off rapidly.
- Rinse tools after use – Clean any pumps, tubing, and sprayers thoroughly after applying tea to prevent slime buildup.
Compost tea works best when integrated as part of an overall organic soil-building program using compost, cover crops, mulch, and other techniques to enhance microbial activity in the root zone.
Timing and Frequency
Compost tea can be applied at any stage of growth, but the timing and frequency depends on your purpose:
- Seedlings – Drench weekly to improve rooting and prevent damping off disease.
- Vegetative stage – Foliar spray or soil drench every 2-3 weeks to encourage vigorous growth.
- Transition to flower – Drench at day 1 of flower to stimulate root mass and flowering sites.
- Flowering – Foliar spray every 2-3 weeks up to mid-flower to increase bud density.
- Ripening – Avoid late flowering/ripening as excess N can delay maturity.
- Any sign of stress – Compost tea can perk up stressed plants and help recover from environmental shocks.
Listen to your plants and adjust your compost tea regimen based on how they respond. Healthy plants with robust white roots probably don’t need excessive amounts of compost tea.
Troubleshooting Common Issues
Despite the benefits, compost tea can occasionally cause some issues if not used properly:
- Leaf burn – Concentrated or hot tea and spraying in direct sunlight can scorch leaves. Dilute tea and spray in evenings.
- Bad smells – Foul odor means the tea went anaerobic. Stick to actively aerated methods only.
- Mold/fungus gnats – Letting tea stagnate for too long can breed problematic molds and pests. Use tea quickly.
- Algae growth – Excessive nutrients and sunlight exposure creates algal blooms. Brew tea in the dark.
- Plugged irrigation – Chunky tea can clog irrigation systems. Use finer filters and flush lines after application.
- Not helping – Tea was either brewed incorrectly, old compost was used, or expectations were unrealistic about benefits.
Most issues can be prevented through proper brewing, fresh tea, strategic applications, and maintaining realistic expectations. Correct any problems in your compost tea process and give it another try.
Comparison to Synthetic Fertilizers
Conventional cannabis cultivation relies heavily on synthetic fertilizers to provide NPK nutrients. However, compost teas offer some key advantages:
- Broad spectrum nutrition – Compost tea contains a full array of micro and macronutrients, not just NPK.
- Improves soil health – Synthetics do nothing to enhance soil biology and structure like compost tea does.
- ** Higher terpene content** – Studies show compost tea increases terpenes and resin production more than chemical fertilizers.
- No salt buildup – Overusing synthetics causes excessive salt accumulation which compost tea helps mitigate.
- Sustainable – Tea relies on locally renewable resources versus synthetics made from finite raw materials.
- No toxicity – Synthetic overdoses burn roots and leaves, whereas compost tea has a much wider safe margin for error.
The drawback is that compost tea provides lower overall concentrations of NPK than most chemical fertilizers, so plants with a high nutritional demand struggle with organics alone. Utilizing both synthetic and organic inputs strategically based on stage of growth is an effective approach.
Conclusion
While making excellent compost tea requires some trial and error, the tangible benefits for your cannabis garden make it worth the effort. Follow the guidelines in this guide and you’ll be rewarded with healthier, more vigorous plants, bigger yields, and premium flower quality using this powerful organic elixir. Raising a thriving weed crop naturally with compost tea will bring you greater pride and satisfaction as a grower.