Comfrey tea is a traditional garden fertilizer made by steeping comfrey leaves in water. Because comfrey leaves are rich in potassium, nitrogen, calcium, and trace minerals, the resulting tea provides a gentle but effective boost for plants, especially heavy feeders and flowering crops.
This tea is best used as a soil drench rather than a foliar spray. It feeds soil life first, which then supports healthier plant growth over time.
Why are comfrey leaves so nutrient-rich?
That’s because comfrey has a deep root system that takes in minerals from the lower soil layers that most garden plants can’t reach. After those nutrients are stored in the leaves, the leaves can become an excellent source of nutrients to distribute to your other plants with shallower root systems.
What You Will Need
You will need fresh comfrey leaves, a large bucket or container, water, and a loose fitting lid or cover. Rainwater is ideal if available, but tap water that has sat out for several hours also works well.
Making the Tea
Harvest mature comfrey leaves, leaving the crown of the plant intact so it can regrow.
Fill your container about halfway with loosely packed leaves. There is no need to chop them, though cutting them into smaller pieces will speed up the process.
Pour water over the leaves until they are fully submerged. Place a loose lid or cover on the container to keep insects out while allowing gases to escape.
Set the container outside, preferably away from living spaces, as the smell can become strong as the leaves break down.
Allow the mixture to steep for one to three weeks. During this time, the leaves will soften and decompose, and the liquid will darken.
Stir occasionally if desired, though it is not required.
Straining and Diluting
Once the tea is ready, strain off the liquid and compost the remaining plant material. The tea should be diluted before use, typically at a ratio of about one part comfrey tea to ten parts water. This helps prevent overfeeding and makes the nutrients more accessible to plants.
How to Use Comfrey Tea
Apply the diluted tea directly to the soil around plants, focusing on the root zone. It is especially beneficial for tomatoes, peppers, squash, cucumbers, potatoes, berries, fruit trees, and flowering plants.
Comfrey tea can be used every two to four weeks during the growing season. Avoid applying it to very young seedlings or stressed plants.
A Note on Safety and Smell
Comfrey tea is intended for garden use only and should not be consumed. The fermentation process produces a strong odor, which is normal. Keeping the container covered and placing it downwind can help manage the smell.