If you’re looking for a low-maintenance plant that works harder than just about anything else in your garden, let me introduce you to comfrey.

This unassuming herb is a permaculture superstar that feeds your soil, makes incredible fertilizer, and even has medicinal properties.

Comfrey (Symphytum officinale) is like having a nutrient mining operation right in your backyard. Those deep roots can reach down several feet, pulling up minerals and nutrients from layers of soil your other plants can’t access.

When the leaves drop or you cut them back, all those nutrients become available to shallow-rooted plants nearby. That’s why you’ll often see comfrey planted around fruit trees, it’s basically a living fertilizer factory.

Getting started

What it needs:

• Partial to full sun
• Moist soil with good drainage
• Hardy in zones 3-9, so it survives nearly everywhere
• Member of the borage family, native to Europe

A word of warning: Comfrey spreads prolifically. Choose your planting spot carefully because it’s committed to staying there. Even small root pieces can regenerate into new plants, making it nearly impossible to remove once established.

When we collect seeds, we place the flowers and seeds into a mesh bag to prevent it from spreading.

Planting and care

The beauty of comfrey is that once it’s in the ground, it pretty much takes care of itself. Plant root cuttings or crowns in spring, water them in, and watch them take off. The plant will die back in winter and return vigorously each spring.

You can harvest leaves multiple times per year, typically 2-4 cuttings depending on your climate. Cut them when they’re still green and fresh, leaving a few inches of growth so the plant can regenerate quickly.

Making comfrey liquid fertilizer

Here’s where comfrey really shines. That liquid fertilizer you can buy at the garden center? You can make something just as good (arguably better) with comfrey leaves and a bucket.

What You’ll Need:

• A bucket with a lid (5-gallon works well)
• Fresh comfrey leaves
• Water
• Patience

The Process:

1. Harvest leaves: Cut comfrey leaves on a dry day. You’ll want enough to fill your bucket about halfway when loosely packed.
2. Fill the bucket: Stuff the leaves into your bucket. Don’t pack them too tightly—you want water to circulate.
3. Add water: Fill the bucket with water until the leaves are completely submerged. You may need to weigh them down with a rock or brick since they’ll want to float.
4. Cover and wait: Put the lid on (trust me, you want a lid) and place the bucket somewhere out of the way. A corner of the garden works perfectly.
5. Let It ferment: Wait 3-4 weeks. The leaves will break down into a dark, nutrient-rich liquid. Fair warning: this stuff smells pretty terrible, which is why we emphasized that lid.
6. Strain and use: After 3-4 weeks, strain out the leaf sludge (which goes into your compost) and keep the liquid. This is your concentrated fertilizer.

How to use your comfrey tea:

Dilute the concentrate about 10:1 or 15:1 with water, it should look like weak tea. Use it to:

• Water vegetable plants every couple of weeks
• Give fruiting plants (tomatoes, peppers, cucumbers) a boost
• Revive plants that look nutrient deficient

The fertilizer is particularly high in potassium, making it excellent for flowering and fruiting plants.

Beyond the garden

While we’re focused on growing here, it’s worth noting that comfrey leaves have been used traditionally for skin issues like burns, scrapes, and bruises when applied externally as a salve.

The roots have similar properties for sprains and strains. However, internal consumption isn’t recommended due to pyrrolizidine alkaloids that may be harmful to the liver.

Comfrey is one of those plants that gives far more than it takes. Plant it once, and it’ll feed your garden for decades. Yes, it spreads aggressively, and yes, the fertilizer smells like something died in your bucket.

But when you see how your plants respond to regular feeds of comfrey tea, you’ll understand why permaculture enthusiasts won’t shut up about this plant.

Give comfrey a permanent spot in your garden, and it’ll repay you with fertility, abundance, and more free fertilizer than you know what to do with.