Liquid fertilizers provide wonderful nutrition to plants, yet given how often they need to be applied they can be quite expensive. Making your own is easy, takes little time and costs nothing if you use your own plants.
Stinging nettle contains many nutrients including a relatively high amount of potassium and calcium salts, iron, and silicic acid. It also contains nitrogen, manganese and copper.
The minerals in comfrey include zinc, copper, sulphur, magnesium, iron, phosphorus, potassium and calcium. It also contains a good amount of nitrogen.
From the above information you can see that when both herbs are used to make liquid fertilizer your plants will be provided with wonderful food, especially the three main elements: nitrogen, phosphorus, and potassium (NPK).
To make the fertilizer, harvest an equal amount of stinging nettle and comfrey leaves making sure you have enough to fill a bucket or the container you're using. As you can see in the above photo, I used old comfrey leaves that needed removing from my plants, and the stinging nettle plants pulled from the garden near the house.
It hurt to pull the nettle plants out, but I have plenty growing wild and need to avoid young grandchildren and my dog being accidentally stung by them while playing in the yard.
The next step is to fill the container with water, making sure to cover the herb material. Cover the container with some type of lid - I use an old plate that fits neatly over the bucket. Then all you have to do is leave the brew sit for about three weeks.
The mixture will smell dreadful so keep it away from the house. When the time is up, strain the mixture through an old sieve or pantyhose into plastic bottles and store until ready for use.
Apply the liquid fertilizer at the rate of 1 part fertilizer to 6 parts water to your plants every 1 to 2 weeks.