How to make a comfrey feed

Comfrey has very deep roots, which means it extracts large quantities of nutrients from far below the soil's surface, inaccessible to other plants. These nutrients are stored in its leaves. By harvesting the leaves and letting them break down, you'll have a rich, dark, nutrient-rich plant food to use around the garden. It's especially rich in potassium, making it the ideal feed to promote flowers and fruits in a range of plants, including tomatoes.

Watch Monty Don explain how to make a liquid comfrey feed in his video, below:

Follow our step-by-step guide to making a comfrey feed, below.

You Will Need

• Comfrey leaves
• Large bucket, or tub trug
• Stone
• Stone, to weigh the leaves down
• Plastic bottles, such as old milk bottles
• Watering can

Step 1

Harvest comfrey leaves from the base of established plants. The hairy leaves can irritate the skin, so wear gloves if necessary.

Step 2

Remove flowers and tough stems, then chop up the leaves and pack them tightly into a water-tight container. If possible, choose a container with a lid, as the solution can smell as the leaves break down. Use a brick to weigh down the leaves.

Step 3

Check on the progress every few weeks. The leaves will break down gradually, releasing a smelly brown liquid. Collect any liquid, storing it in a cool, dark place. Top up with fresh leaves.

Step 4

Dilute the collected liquid at a rate of one part comfrey to 10 parts water - the darker it is, the more you'll need to dilute it. Use the solution as a potassium-rich liquid fertiliser to encourage flowers and fruit set.

You can also make a liquid feed using the leaves of bracken, clover, groundsel, nettles, borage, chicory and strawberries.