Once you've diluted your comfrey tea solution, the best way to apply it is with a regular watering can when dealing with outdoor plants, or a mister or small jug for houseplants. You should take care to only apply the liquid solution to your plant's soil, though, rather than the leaves as it can burn the foliage.
'You can use comfrey tea as a potassium-rich fertilizer to encourage flowers and fruits in a range of plants, such as tomatoes, peppers, cucumbers, squash, berries, and many more,' says Reese. 'Apply the diluted tea directly to the soil around the plants every 2-3 weeks during the growing season.'
The fertilizer can then be used on pretty much all of your plants, although it's important to avoid it on any young or unestablished plants as they can be more sensitive to the concentration of nutrients. 'You should also avoid using it on plants that prefer acidic soil, such as blueberries, cranberries, and rhododendrons,' says Lina. 'This is because comfrey tea has a high pH level and can raise the soil's acidity and harm these plants.'