Horn meal: when, how and for what use?

Horn meal is an organic fertilizer made from cattle horn and hooves. We clarify when and how you can use horn meal to do something good for your plants.

Nitrogen-rich horn meal can be made from cattle horn and hooves [Photo: scubaluna / Shutterstock.com]

Horn meal is a frequently used and relatively cheap organic fertilizer. But what are its advantages and what are its limits? You will quickly find that horn meal has a special composition, so it should be used with care as a fertilizer for lawns, as a rose fertilizer and tomato fertilizer. We also explain to you whether horn meal can do something against clover in the lawn.

Horn meal: origin, properties, composition

Horn meal is an organic fertilizer with a high nitrogen content. We have summarized the important properties in a table below:

Properties of horn meal

Nitrogen content	10-14%
Phosphorus content	1 – 5%
Potassium content	0 – 1%
Calcium content	≈ 6%
Magnesium content	0%
Sulfur content	0.008%
Organic matter content	85%
Duration of action	6 – 8 weeks
PH value	neutral

It becomes clear that pure horn meal can be used almost exclusively as a nitrogen fertilizer. The content of organic substances is quite high, but unfortunately there are hardly any long-lasting effects on the soil properties to be expected. Because sustainable soil fertilizing effects are prevented by the high nitrogen content in combination with the small grain size. The relatively close C / N ratio (i.e. the ratio of the carbon content to the nitrogen content) and the good accessibility for microorganisms means that around 55% of the nitrogen contained is mineralized in a short time and thus made available for plants. The nitrogen is absorbed and the “packaging” of the nutrients – the carbon compounds – are breathed in as carbon dioxide (CO2) through the nutrition and respiration of the soil organisms. Overall, horn meal is a slowly flowing, i.e. not immediately available nitrogen fertilizer for plant nutrition.

Tip: Even human horn – hair, fingernails and toenails – has almost exactly the properties that are listed in the table above. So they could theoretically also be used as nitrogen fertilizers.

Where does the horn meal come from?

When animals are slaughtered for human consumption, there are naturally a lot of leftovers that are not used in the food industry. The horns and hooves of cattle and pigs, for example, are processed into horn fertilizers in order to make the nutrients they contain usable again. The renewable raw material horn is – just like large quantities of meat – also imported from abroad. Horn fertilizers are differentiated according to their grain size: There are coarse horn shavings (grain size> 5 mm), medium-coarse horn meal (grain size 5 – 1 mm) and finely ground horn meal (grain size <1 mm).

Horn meal is made from horn and claws from slaughtered cattle [Photo: Anton Havelaar / Shutterstock.com]

Tip: If the distribution of ground animal remains in the garden “stinks” – either literally or figuratively – you can use animal-free organic fertilizers to provide your garden with even more sustainable nutrients. Possible products are, for example, the mainly organic and animal-free Plantura organic fertilizers developed by us, which we present to you in this article.

Benefits of horn meal

What are the advantages of horn meal compared to a mineral nitrogen fertilizer or the coarser variant – horn shavings and horn semolina?

Compared to mineral nitrogen fertilizers, there are some clear pluses, because horn meal …

1. … is a renewable raw material
2. … is obtained with much less energy than “artificial fertilizer”
3. … is usually cheaper than “artificial fertilizer”
4. … is only mineralized in the soil, which is why over-fertilization, salt damage and leaching into the groundwater are almost impossible
5. … is gradually mineralized, creating a long-term effect

Compared to long-term mineral fertilizers, however, horn meal also has disadvantages:

• Since its implementation depends on temperature and humidity, a release on warm spring and autumn days can unfortunately lead to leaching. In these situations the soil is warmed up and active, but the plants are not yet able to absorb nutrients or are already unable to absorb them – so the risk of leaching is high.
• The speed of action of long-term mineral fertilizers is significantly higher: As soon as they have been applied, mineralized nitrogen is already present.

Compared to the coarser horn fertilizers, horn meal has only one advantage: Due to its fine grain size, it is converted more quickly so that the nitrogen it contains is available more quickly. The release of mineral ammonium nitrogen begins after just a few days. In return, its fertilizing effect only lasts six to eight weeks. Horn semolina and shavings are implemented more slowly, but longer. The effect of horn semolina lasts for two to four months, that of horn shavings even four to six months. This mode of action can of course also be seen as an advantage.

Although horn meal works faster than horn shavings, you should remedy such an acute deficiency with mineral fertilizers [Photo: Sarah2 / Shutterstock.com]

By the way: Even if a fertilizer has been released, it usually takes several days to weeks before you can observe an effect on the fertilized plants. This depends not only on the type of fertilizer given, but also on the weather, the season, the plant and its other nutrient supply.

Summary advantages and disadvantages of horn meal:

1. Horn meal is much more environmentally friendly and user-friendly than mineral nitrogen fertilizers
2. If used incorrectly, nitrogen can also leach out from horn meal, which pollutes the groundwater
3. Long-term mineral fertilizer works much faster than horn meal
4. Horn meal is mineralized faster than horn meal or horn shavings. However, the quick effect comes at the price of a shorter duration of action

Horn meal in the garden

What is certain is that ground horn can be used in the garden as an organic, relatively fast-acting nitrogen fertilizer. However, the effect can differ from garden soil to garden soil: Since the release of the nitrogen contained is only possible with the help of active soil life, it takes place more quickly in healthy garden soils with a lot of humus than in humus-poor, too dry or too humid locations or those with too little PH value.

When and why should horn meal be used?

Since horn meal only contains nitrogen in large quantities, it only makes sense to use horn meal alone if all other nutritional elements are present in sufficient quantities. If this is not the case, you should use a complete fertilizer or an NPK fertilizer, which are discussed in detail in our special articles linked here. Other organic fertilizers also contain all the necessary nutrients in an environmentally friendly form, as you can find out here.

The bloom of the forsythia heralds the spring and with it the growing season [Photo: taylon / Shutterstock.com]

Since horn meal takes about a week on average to start the release, you should fertilize with foresight. The first fertilization takes place at the beginning of the vegetation period, i.e. as soon as the vegetation wakes up from hibernation. Depending on the altitude and region, the beginning and duration of the vegetation period is different. The German Weather Service names the forsythia ( Forsythia x intermedia ) bloom between March and May as a sign of the beginning growth period. After the first fertilization, you can then re-fertilize about six weeks apart. After the end of September, however, no more fertilization should take place. According to the German Meteorological Service, the end of the growing season is marked by the fall of leaves from the pedunculate oak ( Quercus robur ) and no more nitrogen should be released at this point.

Fertilize the lawn with horn meal

Nitrogen fertilizing lawns with horn meal requires that you start fertilizing in good time. The significantly delayed effect also requires that the first fertilization be carried out early (March to April) and then at regular intervals every six weeks. About 50 grams of fertilizer are applied per square meter – so 5 kilograms of horn meal are sufficient for 100 square meters. Alternatively, you can start with horn meal and continue fertilizing with horn semolina or horn shavings in order to lengthen the fertilization interval. Since a sufficient supply of potassium should be guaranteed in preparation for winter, you can start using a potassium-accentuated autumn lawn fertilizer such as our Plantura organic autumn lawn fertilizer from July. You can read all about preparing your lawn for winter here.

In order to guarantee a sufficient supply of potassium over the winter, you should fertilize the lawn with a potassium-accented autumn lawn fertilizer from July

Fertilize tomatoes with horn flour

Fertilizing tomatoes with horn meal alone is impossible. It can only succeed if you supplement the missing nutrients with other fertilizers. However, since tomatoes have a high nutritional requirement and are also sensitive to nutrient deficiencies, you should always keep a close eye on the supply of your plants. We recommend fertilization in combination with a nutrient-rich ready-made compost at the time of planting. The second application of fertilizer should be done by mid-July. Growing tomatoes with our Plantura organic tomato fertilizer, which is perfectly tailored to the needs of your tomatoes, is more convenient than with several simple fertilizers.

Tip: Fertilizing vegetables with horn meal is sometimes more, sometimes less useful: Long-standing crops such as tomatoes, peppers, aubergines, cucumbers or pumpkins can be supplied with nitrogen with the slow-flowing fertilizer. However, crops that grow quickly and will soon be cleared again, such as lettuce or radishes, are being harvested when the horn meal is fully effective. Here too, predictive fertilization is a must.

Fertilize roses with horn meal

The fertilization of roses with horn meal is suitable to meet the nitrogen requirements of this graceful wood. But other nutrients are also required for the formation of impressive flowers and strong, resistant shoots. A combination of horn meal and compost is ideal: In March, the first dose of 3 liters of compost and 25 grams of horn meal per square meter, followed by a second dose of 25 grams of horn meal per square meter at the beginning of July.

Fertilizing with horn meal and compost can optimally cover the nitrogen requirements of roses [Photo: Muellek Josef / Shutterstock.com]

How do you use horn meal correctly?

The information previously compiled in the text can be found here again summarized in bullet points.

1. Horn meal is an organic nitrogen fertilizer with a long-term effect that is suitable for fertilizing plants. It cannot be used, or only barely, for soil improvement
2. Since the release of nitrogen from horn meal only begins after a few weeks and ends after eight weeks, it is necessary to fertilize and re-fertilize with foresight
3. The sole fertilization of horn meal only makes sense if the treated soil is adequately supplied with all other nutrients
4. Vegetable crops with very short standing times do not benefit much from horn meal fertilization if this is not done long before planting or sowing
5. In general, the first fertilization of the year with horn meal takes place between the beginning of March and the beginning of May. The last fertilization with horn meal should be done in July. In order to ensure a good frost resistance (for all perennial crops), from this point in time at the latest, you must fertilize with rapidly available potassium – for example “patent potash”

Horn meal versus clover?

Although clover is a bee pasture and pretty to look at, it annoys many garden owners in the lawn. The clover ( Trifolium ) is a legume and therefore gets along much better on nitrogen-poor areas than other plants. The reason for this is the symbiosis that legumes enter into with so-called nodule bacteria. These bacteria ( rhizobia ) are able to bind atmospheric nitrogen and convert it into ammonia (NH3). This in turn is converted into usable ammonium (NH4 +) in the plant. Thus, the clover is adapted to a nitrogen-poor subsoil and has a clear advantage over the poorly growing lawn.

Clover in lawns is beneficial for bees, but is generally undesirable [Photo: katiko.dp / Shutterstock.com]

Another characteristic of clover is that it loves both potassium and phosphorus. The following conclusions can be drawn from these considerations:

1. There is an urgent need for nitrogen fertilization
2. You should avoid fertilizing with phosphorus or potassium at first

Since horn meal contains a lot of nitrogen and hardly any potassium or phosphorus, it meets these two requirements perfectly. Fertilizing with horn meal can help with an undersupplied lawn that is filled with clover. After the one-time fertilization with horn meal, you should switch to regular fertilization of your lawn with a lawn fertilizer. For this you can also use an animal-free, mainly organic lawn fertilizer like the one we have developed. The clover only has a chance against inhibited lawn plants. Optimal care is therefore the best precaution to avoid clover.

In addition to nitrogen depletion, too high a pH can also encourage clover to grow. The optimal soil pH value for lawns is 6.0 to 6.5. This area can quickly be exceeded by too frequent liming or an unfavorable subsurface. So it can make sense to test the pH of your soil under the lawn and avoid liming for the next few years. The use of ammonium in nitrogen fertilization can help actively lower the pH, as this leads to acidification of the soil.

Tip: If the clover has already overgrown entire areas and completely displaced the lawn there, you should cut out a large area and remove it. But make sure to also collect pieces of roots and shoots, because the clover can regenerate from these. When sowing new lawn, you should also make sure to use the same seed mixture that was used to plant the lawn.

After fertilizing with horn meal, you should switch to regular fertilization with a full-fledged lawn fertilizer

Summary of horn meal versus clover:

1. The growth of clover is favored when the soil is poor in nitrogen
2. Phosphorus and potassium also promote clover
3. Fertilizing with horn meal provides the lawn with the nitrogen it needs to survive and push back the clover
4. After fertilizing with horn meal, you should switch to regular fertilization with a full-fledged lawn fertilizer
5. Too high a pH can also encourage clover to grow
6. Refraining from liming and covering the nitrogen requirement with ammonium fertilizer can lower the pH value, provided a value above 6.5 has been demonstrated
7. If the clover has already displaced large areas of the lawn, only re-sowing will help

Buy horn meal: where do you get horn meal from?

Horn meal is a simple fertilizer and for this reason it is usually cheaper than complex organic fertilizers. Nevertheless, the price is higher than that of the even cheaper mineral nitrogen fertilizers – ammonium sulfate nitrate or urea fertilizers, for example. There are hardly any qualitative differences between the various providers, so choosing the cheapest product is definitely okay.