How to Make Compost Tea
Compost tea is a water extract made from mature, finished compost, and it is best treated as a modest soil amendment rather than a replacement for fertilizer or disease control. For the lowest-risk home approach, make a simple non-aerated extract, use clean equipment and finished compost, and apply it to soil promptly.
Start only with fully finished compost that smells earthy, is dark and crumbly, and contains no recognizable fresh food scraps or manure. Do not use immature compost, material from a bin that has gone anaerobic, or compost of uncertain origin. Clean the bucket, stirring tool, and any strainer before use.
Place finished compost in clean water and stir thoroughly to make an extract. Let larger particles settle briefly, then strain if needed so solids do not clog application equipment. Do not add sugar, molasses, manure, or other nutrient-rich ingredients, because these can encourage unwanted microbial growth.
Use the extract soon after preparation rather than storing it. Apply it to the soil around established plants or to garden beds before planting, using a watering can or other clean soil-application method. Avoid using it as a substitute for regular irrigation, and avoid relying on it to correct a nutrient deficiency.
Do not make claims that compost tea will prevent or cure plant diseases. Research results on brewed compost teas are inconsistent, and home preparation methods are difficult to standardize. Good garden sanitation, appropriate spacing, resistant varieties, sound watering practices, and diagnosis through Cooperative Extension remain more dependable disease-management tools.
If your garden needs nutrients, begin with a soil test and use compost, amendments, and fertilizer according to the results and crop needs. A compost extract contains unpredictable and generally low nutrient concentrations. It should not replace a fertility program for vegetables, fruit trees, or other productive crops.
Keep preparation and application simple. Wear gloves when handling compost, wash hands and tools afterward, and keep the mixture away from harvested produce and indoor food-preparation areas. If you use any commercial input or plant-protection product in the garden, follow its label and local Cooperative Extension guidance.
Frequently asked questions
What compost should I use for compost tea?
Use only mature, finished compost that is dark, crumbly, and earthy smelling, made from known materials.
Should I add molasses or sugar to compost tea?
No. Added sugars can encourage unwanted microbial growth and are unnecessary for a simple compost extract.
Can compost tea replace fertilizer?
No. Its nutrient content is variable and usually low. Use soil-test results to guide fertility decisions.
General guidance for US home gardens. Conditions vary by region and season; check with your local Cooperative Extension office for site-specific advice. Page updated Aug 4, 2026.