Organic Fertilizer: Definition & Benefits

Organic fertilizers promise a thriving garden with a clear conscience. We take a closer look at the pros and cons of organic fertilization.

Organic fertilizers often give off an unpleasant smell, but they are still on everyone's lips. The ominous brown mixes seem to be a boon to garden fertility and nature's he alth. In this article we would like to give you a definition of organic fertilizers and give you details about their properties, how these fertilizers work and what advantages and disadvantages they have. Then we will introduce some types of organic fertilizers and explain how to make organic fertilizer yourself.

Definition: what is organic fertilizer?

Organic fertilizers are those that contain nutrients in organically bound form. The raw materials used in them can be of animal or vegetable origin. Unlike mineral fertilisers, the plant nutrients are not in the form of s alt, which quickly dissolves in soil water, but are packed in natural structures. In order for plants to be able to use them, these structures must first be broken down. Soil organisms take over this task and mineralize the components of the fertilizer. That means they break them down into their individual molecular and atomic parts. The contained plant nutrients, which were previously "built in", are released again in this way. They get into the soil solution like the s alt in a mineral fertilizer and can be taken up again by plants to form new organic structures.

Tip: Depending on the soil conditions, another process occurs in addition to mineralization: humification. This creates hummus. Because this can also be mineralized again if the soil life is very active, the processes of mineralization and humification constantly work against each other. If the conditions remain the same, an equilibrium will be established which will increase the humus content of your soilDefinitely.

Summary: What is Organic Fertilizer?

• The nutrients in organic fertilizers are bound in organic structures
• In order to make the nutrients usable, these structures must first be broken down by microorganisms
• After decomposition, the nutrients contained can be absorbed by the plants like those from mineral fertilizers

Organic Fertilizer: Extraction and Manufacturing

Raw materials for organic fertilizers can be various plant or animal substances. The range of nutrients and their concentration are usually decisive for the selection. Basically, all plants need the same 14 essential nutrients. Conversely, any fertilizer made from plants must contain all of these nutrients. Animals also need these elements - and a few more - or at least get them from their food. Therefore, their components and legacies are also suitable for fertilization. Ultimately, which raw materials are actually used is often a question of concentration: if a raw material only contains small amounts of a desired nutrient element, it is of course less suitable for fertilization - if fertilization is only defined as the supply of nutrients - than if it contains a large amount includes.

Tip: A fertilizer made from raw materials with a low nutrient content can also be a "good fertilizer". Namely insofar as such a fertilizer contributes to the formation of humus and thus to the improvement of soil properties. These are just as important for plant growth and have a significant impact on how effectively nutrients and water can be stored and used by plants. Since organic fertilizers fertilize the plants through the supply of nutrients and also the soil through the input of organic material, one speaks of plant and soil fertilizers.

Organic fertilizer raw materials supply to a greater extent:

• Animal production through excrement, bone, blood and horn products
• The food industry through unused by-products such as skins, residues from alcohol fermentation and many other areas
• Waste management through recycling of organic household waste and green waste
• In the case of agriculture, in some cases, waste water management through sewage sludge

Manufacturing of fertilizers includesthe crushing and drying and, depending on the origin, the mixing of different raw materials from different origins. The goal is to always achieve a consistent composition and nutrient content. Pelletized fertilizers are then pressed into shape with a binder of natural origin. To produce liquid fertilisers, the fertilizer is very carefully crushed and then dissolved in water. This is strained last to get the liquid fertilizer.

Summary: Extraction and Production of Organic Fertilizers

• Organic fertilizers can be made from animal or vegetable raw materials
• The raw materials chosen for plant fertilizers contain high concentrations of organically bound nutrients

Effect and nutrient content of organic fertilizers

In general, an organic fertilizer acts both as a plant fertilizer - i.e. by adding nutrients - and as a soil fertilizer - by improving the soil properties. The higher the nitrogen content and the lower the content of persistent substances, the greater the plant fertilizing effect. For example, all lignified parts of plants and those containing fats or tannins are difficult to degrade.

Humus reproduction high	Humus reproduction medium	humus reproduction low
Low Nitrogen Fertilizer ("Soil Fertilizer")		Fertilisers with high nitrogen content ("plant fertilizers")
Woody Materials, Rice Husks, Coconut Shells	Leaves of deciduous trees, bark compost	Slurry and liquid manure
Bark chaff, conifer needles, sawdust, straw	Green manure	Chicken droppings, biogas manure
Compost from nutrient-poor material as mentioned above	Mixed material compost, mixtures of nitrogen-poor and nitrogen-rich material	Compost from nutrient-rich material such as garden vegetable leftovers, lawn clippings and kitchen scraps
Nutrient input low	Nutrient input medium	Nutrient input high

The effect of the organic fertilizer depends on its respective composition. Other factors also have a significant influence on the effect of a fertilizer, such as soil temperature and moisture and the pH value. We would like to explain the sub-steps of the two processes to you here only in note form. For more complete information on humus farming seeour special article.

Humification

1. Mechanical crushing and mixing with the soil by larger soil organisms such as earthworms
2. Delayed degradation of organic matter
3. Enrichment of more and less heavily decomposed parts of material
4. Release of ingredients from degraded structures to a small extent
5. Chemical reactions (oxidations) and cleavage by enzymes from soil organisms convert raw materials in such a way that they can combine into new structures
6. This is how dark brown to black organic compounds called humic substances are formed
7. The sum of the humic substances forms the soil humus

Mineralization

1. Mechanical crushing and mixing with the mineral soil by larger soil organisms such as earthworms
2. Degradation by microorganisms such as bacteria and fungi
3. Breaking down of the organic compounds into the molecular building blocks by enzymes of the microorganisms. Release and further conversion of nitrogen, phosphate, sulphur, potassium, calcium, magnesium and other plant nutrients, which can then be taken up by plants
4. Microorganisms use the building blocks released in this way to build their own body structures, nitrogen is used as a source of energy. At the end of their lifespan, they too fall prey to the degradation and conversion processes

Summary: How Does Organic Fertilizer Work?

• Organic fertilizers are always both plant and soil fertilizers
• Plant fertilizers ensure increased nutrient input, soil fertilizers improve soil properties
• The more nutrients and the less difficult-to-decompose material an organic fertilizer contains, the more likely it is a plant fertilizer and provides plant nutrients through mineralization
• The fewer nutrients and the more hard-to-decompose material an organic fertilizer contains, the more likely it is a soil fertilizer and increases the humus content of the soil through humification
• Whether humified or mineralized depends on various factors. In both cases, soil organisms are significantly involved

Organic Fertilizer: Pros and Cons

Like mineral fertilizers, organic fertilizers have their good and bad sides. We have summarized these advantages and disadvantages for you in bullet points.

Benefitsof organic fertilizers

• Replenishment of all important plant nutrients
• Improvement of soil properties (nutrient retention capacity, water capacity, root penetration, soil structure, promotion of soil organisms) by promoting humus formation
• Due to slow implementation, there is little or no risk of over-fertilization or leaching; therefore very safe and easy to use

• Natural long-term effect, conversion dependent on temperature and humidity largely prevents release from taking place if there is no plant growth
• Production requires less energy and is therefore more ecologically justifiable, since renewable raw materials are used instead of fossil deposits
• Can also be used as liquid fertilizer
• Also vegan, i.e. animal-free available

Disadvantages of organic fertilizers

• Nutrient concentration lower than in mineral fertilizers
• Potassium content too low in some products; in this case it must be supplemented with minerals
• Slow implementation enables short-term or timely fertilization only to a small extent and with only a few products (e.g. animal meal and organic liquid fertilizers with faster implementation)
• Release depending on the weather varies: Cold soils in spring can experience a lack of nutrients, in autumn due to still warm and rainy soil, nitrogen in particular can be washed out
• Prices are often slightly higher than those of mineral fertilizers

Tip: How important is it for you as a user to improve soil properties and form humus? A humus-rich soil offers the optimal growth conditions for most garden plants. It needs to be watered less often because it can store a lot of water. Due to the elasticity of the humus crumbs, it always remains loose and allows the roots to penetrate deeply. The soil can also store many nutrients and the supply is always even. And these are just a few of the benefits you can enjoy from a humus-rich garden soil. Here you will find our special article on the subject of hummus with further information.

Organic Fertilizer vs Mineral Fertilizer

A direct comparison of organic and mineral fertilizer makes the differences even clearer.

Fertilizer property	Organic Fertilizer	Mineral Fertilizer
Casting Speed	Slow to medium	Fast
Nutrient Release	Slow Flow	Focused
Nutrient Content	Low to High	Medium to High
Promotion of soil life	Yes	No
Promotion of humus formation	Strong	Little to none
Preservation/improvement of the soil structure	Yes	No
Application Security	High	Low
washout drive	Low	High
Influencing the pH value	No	Depending on the fertilizer used
Release weather dependent	Yes	No
Price	Higher	Minor

Tip: Mineral fertilizers can affect the pH of the soil. For example, ammonium nitrogen leads to a reduction in pH, while nitrate nitrogen leads to an increase in pH. Complete fertilizers and other mixtures are composed in such a way that there is no significant change in the pH value. This danger only exists when fertilizing individual nutrients.

Summary: Organic vs Mineral Fertilizer

• Organic fertilizers have a slower rate of action and release than mineral fertilizers
• Organic fertilizers promote soil life and humus formation, which improves soil structure

Organic mineral fertilizer

Organo-mineral fertilizers are fertilizers that contain components of both types of fertilizer. They therefore represent a compromise that is also reflected in their properties: their speed of action and the concentration of nutrients they contain can be quite high, and the release occurs both in the short and long term. They promote soil life, but contribute significantly less to the formation of humus than purely organic fertilizers. Since they contain mineral components, leaching and over-fertilization can occur. However, the levels of mineral nutrients are lower, so the damage is limited. The price of organo-mineral fertilizers can be in the medium to very high range and is often dependent on themanufacturer and the area of application.

Summary: Organic Mineral Fertilizer

• Organic mineral fertilizers contain both organic and mineral ingredients
• The combination of opposing properties results in a fertilizer with a few advantages and few disadvantages in terms of humus formation, speed and duration of action or the risk of leaching

Buy Organic Fertilizer: Examples

Organic fertilizers have found their way into all areas and are enjoying increasing popularity. Here we provide you with some examples of organic fertilizers in the most important areas of application.

Organic Lawn Fertilizer

Organic lawn fertilizers such as our primarily organic Plantura organic lawn fertilizer have the advantage that their slow release enables even growth. In principle, however, the potassium requirement of lawns in summer is lower than in autumn and winter. Autumn fertilization is therefore carried out with an increased potassium content, which can be found, for example, in our special Plantura organic autumn lawn fertilizer. This is of purely vegetable origin and is therefore also suitable for users who find the smell of animal meal and animal excrement unpleasant. You can find out more about our Plantura organic fertilizers here.

Organic Slow Release Fertilizer

Organic fertilizers have a natural long-term effect. They are particularly user-friendly if they also provide nutrients for plants quickly after application. Horn shavings are used in many places: they mainly contain nitrogen and are often offered quite cheaply by various manufacturers. However, since these products hardly contain any other nutrients, they should also be fertilized to avoid malnutrition in the plants.

Organic Complete Fertilizer

To bear this designation, a complete fertilizer must contain at least the three main nutrients nitrogen, phosphorus and potassium. Organic fertilizers usually also contain many other nutrients, but only in smaller or very small amounts. Our Plantura universal fertilizer is also a primarily organic complete fertilizer, which is even animal-free and therefore very environmentally friendly. The same applies to our Plantura organic flower fertilizer, for balcony and summer flowers as well as richly flowering onesPerennial beds supplied with nutrients in a long-term and environmentally friendly way.

Organic Liquid Fertilizer

Liquid fertilizers have the advantage that they work particularly quickly. This also applies to organic liquid fertilizers, but unfortunately these cannot always be used as foliar fertilizers. Therefore, carefully follow the instructions for use on the packaging. Compared to an organic solid fertilizer, the proportion of organic matter in liquid fertilizers is of course marginal.

Organic Phosphorus Fertilizer

If one speaks of organic phosphorus fertilizer, the so-called guano is usually meant. The high levels of phosphorus and nitrogen in the limestone rocks of South American coasts altered by seabird excretions were discovered in the 19th century. As a result, this mixture of faeces and lime was increasingly used as a nitrogen and phosphorus fertilizer in agriculture. Pure guano fertilizer contains nitrogen, phosphorus and potassium in a ratio of about 3:5:1. However, since this ratio is not optimal for plants, it is usually offered in mixtures with other organic fertilizers.

Bat guano is made in a similar way to seabird guano. This is mined in caves inhabited by bats in Spain, Italy and America. This bat guano fertilizer contains nitrogen, phosphorus and potassium in a ratio of 4:8:1 and is therefore hardly suitable for supplying plants on its own. In addition, bat guano harvesting is very controversial due to the disturbance of bat habitats.

Organic fertilizer in agriculture

Organic fertilizers used in agriculture are generally those that fall into the “manure” category. What is meant by this is that they are products of livestock farming and occur in the operation of fattening stables. Sewage sludge from the wastewater industry can also be used in some crops. A particularly valuable fertilizer is stable manure, which is a combination of liquid and solid excrement and bedding material such as straw. The urine excreted by farm animals, which contains almost only nitrogen and potassium, is called liquid manure. Manure, on the other hand, is the mixture of faeces and urine and thus forms a kind of "middle ground" between stable manure and liquid manure. The nutrient content can vary greatly depending on the species.

By the way: These are the big problems of nitrate pollution of groundwaterResult of livestock farming, which is practiced too intensively, especially in Lower Saxony. Because while fields and fields do not need fertilization in the cold season, the cattle naturally continue to produce faeces and urine. If this is applied without the nitrogen it contains being able to be absorbed by plants, nitrate is washed out into the groundwater. With the new Fertilizer Ordinance, which came into force in 2022, prohibition periods are now in place to protect the groundwater in winter.

Make organic fertilizer yourself

If you run a compost heap with nutrient-rich material such as vegetable scraps, lawn clippings or pet bedding, you will have a potent fertilizer in at least two years. However, the production is very time-consuming and the large volume of the end product sometimes interferes with use. Therefore, below you will find two simple recipes to make organic fertilizer yourself.

Organic Fertilizer from Straw

The composting of straw turns the material that is difficult to decompose in combination with a very nutrient-rich fertilizer into a valuable mixture that forms humus and provides nutrients.

How to successfully compost straw:

1. Spread a 20 cm layer of straw on a compost heap or in a box in a shady place (e.g. barn, shed or garage)
2. Wet the straw until completely soaked
3. Sprinkle or water the straw with a nitrogen-rich fertilizer. This can also contain only nitrogen
4. Stack several 20 cm thick layers of straw, which you also moisten and fertilize
5. Mix the layers once a month from now on
6. After a few months, the straw will have rotted away, a whitish coating may have formed. You can now use it to fertilize soil and plants

Manure manure

A large tub or mason's bucket, fine-mesh potato netting, some manure, ash, and rainwater can be used to make an effective liquid fertilizer that contains all three key nutrients.

1. Use well-rotted manure. It should be dry, crumbly and no longer smell bad
2. Mix wood ash into the manure to add the potassium content of the later liquid fertilizerincrease
3. Stuff the mixture into the potato web. This is firmly knotted and hung in the container with rainwater. A whole potato net is enough for a ton with a capacity of 200 liters
4. Wait a few weeks, stirring occasionally. If the liquid inside the barrel clears, the production is successful
5. Only use the liquid fertilizer diluted. The finished fertilizer mix should be about the color of faint black tea

We have compiled more information about our Plantura fertilizers here for you.