Fertilizing with sheep wool

In fact – from sheep’s wool can only knit sweaters, but also fertilize plants with it. We took a look at why and how this works.

What makes sheep’s wool so valuable?

Sheep’s wool consists mainly of keratin – a fibrous protein that also makes up our hair. Basically, wool has a similar composition to horn shavings and, as a natural and organic slow-release fertilizer, provides the plants with nitrogen (up to 12%), potassium, sulfur, magnesium and, in small quantities, phosphorus. The pH value of 7 to 8 is in the neutral or slightly basic range.

The keratin is gradually decomposed in the soil. Depending on the weather, it takes at least a year for the wool to “disappear”, i.e. to be converted into plant-available nutrients. Overfertilization is therefore not possible.

In addition to its function as a nutrient supplier, sheep’s wool is also a good water reservoir. Once soil organisms have broken down the water-repellent wool grease (lanolin), the wool absorbs water like a sponge and slowly releases it back into the soil. This swelling effect not only ensures a more even water supply for the plants, but also loosens the soil.

By the way, the use of sheep’s wool as fertilizer is not new. Centuries ago, wool was already buried in the soil by farmers and gardeners.

How do I fertilize with sheep wool?

Sheep wool fertilizers are suitable (with the exception of bog plants) for all plants, whether perennials, woody plants, berry bushes or vegetable plants. Potted plants and houseplants also benefit. Sheep’s wool is particularly suitable for high-yielding plants such as tomatoes or potatoes.

Sheep wool can be shorn directly from the sheep and used in the garden as fertilizer. For this, it does not need to be washed or otherwise processed. The wool is simply roughly shredded by hand and added to the planting hole for new plantings. For existing plantings, the wool is spread around the plant, covered with some soil and watered well.

Meanwhile, there are also sheep wool pellets that are dosed like fertilizer granules, sprinkled either into the planting hole or around the plant and lightly incorporated. This makes the pellets easier to use than unprocessed wool. However, their industrial production is more complex: first the wool is crushed, dried by means of heat and finally pressed into pellets. Sheep wool-based fertilizer pellets often have phosphate or other nutrients added to them to ensure that they always have the same nutrient content.

Where can I get sheep wool?

Shepherds and sheep farmers produce a lot of wool, which is sometimes simply disposed of because of the quantity or low market value. Often, heavily soiled wool is also discarded because it is not suitable for industrial processing – however, this unwashed, perhaps even somewhat mishandled reject wool is the ideal fertilizer. Find out if there is a sheep farmer in your area where you can get the wool cheaply, or perhaps even for free.

Sheep wool pellets are available at garden supply stores or online.