Left to macerate in rainwater, comfrey leaves collapse into slime and the liquid turns blackish: that is the sign the tea is ready. Rich in potassium, calcium and nitrogen drawn up by a root that dives a metre underground, it feeds growth and bloom, and repels parasites when diluted further.
This liquid manure also works as a parasite repellent and compost activator.
Thanks to its high organic matter content, especially potassium, calcium and nitrogen, comfrey tea is an effective growth and blooming enhancer.
Comfrey is a taproot plant. Its main root dives deep underground, where it finds nutrients that aren’t as available in the topsoil. Indeed, sometimes it reaches depths of 2-3 feet (1 meter). Only trees have a similar reach.
This unique characteristic explains why it’s more effective as a fertilizer than other weed fertilizers.
Comfrey tea at a glance: which dilution for which job
The same batch of fermented comfrey tea does several jobs in the garden, the difference being how much you dilute it before spraying. Here is what the brew is used for, and how strong each mix needs to be.
Comfrey tea at a glance: which dilution for which job
Use
Dilution
When to apply
What it does
Fertiliser
10% tea to 90% water
Throughout the growth and flowering phase
Enhances growth and blooming
Parasite repellent
5% tea to 95% water
Throughout the growth and flowering phase
Keeps parasites off the foliage
Compost activator
—
—
Gets the compost heap working
Fermented stinging nettle tea (alternative)
—
—
Chosen when higher nitrogen levels are wanted
One maceration therefore covers feeding, pest deterrence and the compost heap.
Recipe for 10 quarts (10 liters) of comfrey tea
Ready when the liquid has turned blackish
Harvest 35 oz (1 kg) fresh leaves.
Macerate in 10 quarts (9 liters) rainwater (softer) for 1 to 2 weeks.
Avoid using metallic containers for maceration.
Mix regularly.
Fermented comfrey tea is ready when the liquid turns blackish and leaves turned into slime at the bottom of the container.
Filter to remove any residues and produce a perfectly clear liquid.
Using fermented comfrey tea
Fermented comfrey tea can be used during the entire vegetation and blooming phase of plants and vegetables.
Fresh leaves macerate in rainwater for one to two weeks
It is used like any other fertilizer with a mixing ratio of 10% fermented comfrey tea to 90% water.
If my hand sprayer contains 9 quarts (9 liters) water, I’ll add 1 quart (1 liter) fermented tea and have a great plant fertilizer.
It is used like any other parasite repellent with a mixing ratio of 5% fermented comfrey tea to 95% water.
If my sprayer contains 9.5 quarts (9.5 liters) water, I’ll add ½ quart (½ liter) fermented tea.
Images: depositphotos: Martina Unbehauen; own work: Rosalyn & Gaspard Lorthiois; Pixabay: Nancy Buron
Written by Gaspard Lorthiois | Loves helping out, especially when it comes to growing things. Worked in herbal medicine, runs a farm, and dabbles in tech. Master's degree and engineer.
