Complete fertilizers are fertilizer mixtures that can differ in composition, price and application. Here you get an introduction to the topic.
The complete fertilizer - an omnipotent all-rounder? In this article you will learn what a complete fertilizer is and what its limitations are. We also provide you with a few examples of well-known complete fertilizers, name the advantages and disadvantages and give tips on how to use them. And to protect you from outrageous offers, we're adding a rough price classification.
What are compound fertilizers?
In practice, all fertilizers that contain the three plant nutrients nitrogen (N), phosphorus (P) and potassium (K) are referred to as complete fertilizers. So every NPK fertilizer is automatically a complete fertilizer. A detailed article on the subject of NPK fertilizers can be found here. To find out what a fertilizer contains, look on the packaging for information about the nutrients it contains. The declaration always follows a similar pattern. The plant nutrients - i.e. the chemical compounds in which the nutrient elements are present - are given as a percentage. The declaration, such as with our Plantura organic tomato fertilizer.
4 - 3 - 8 + 2 MgO, means the fertilizer contains 4% nitrogen, 3% phosphorus, 8% potassium and 2% magnesium.
The order in which the elements are listed is always N - P - K - Mg - S. Other ingredients are also specified in the declaration.
If you are not familiar with the terms of nutrients, here is a brief overview of the 14 essential nutrient elements of plants:
The main nutrient elements: N, P and K are among the "macro nutrient elements", i.e. the nutrient elements that plants need in larger quantities. There are also other macronutrient elements.
Nitrogen (N) is involved in building proteins and DNA. It is also an important component of chlorophyll, the green plant pigment. This enables the plant toPhotosynthesis.
Phosphorus (P) is also an important component of proteins and DNA. In addition, it becomes the "energy currency" of all cells in plant cells in the form of a special chemical compound. Phosphorus also promotes the formation of flowers and fruits.
Potassium (K) regulates the water balance of the plant and makes it resistant to frost and drought. By supporting cell wall construction, it promotes stability and resistance to fungal diseases and sucking insects.
Other macronutrients: Magnesium (Mg), Calcium (Ca) and Sulfur (S) are required by plants in slightly lower amounts.
The trace nutrients iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B), molybdenum (Mo), nickel (Ni) and chlorine (Cl) are found in very small amounts Quantities needed.
Tip: Even if the micronutrient elements are required in very small amounts, they are just as essential for plants as the macronutrient elements. However, they may only be given to them in very small doses, otherwise damage to the plants may occur. It applies to all plant nutrients: "The dose makes the poison".
Summary of the definition of complete fertilizer:
- A complete fertilizer contains the three main nutrients nitrogen, phosphorus and potassium
- It can also contain other macronutrients and trace elements
- The declaration is always made in the following order: N - P - K - Mg - S
- The 14 essential nutrients in plants fulfill different tasks in the plant metabolism
- For all plant nutrients, both a deficiency and an excess can damage the plant
What complete fertilizers are there?
Complete fertilizer is not the same as complete fertiliser: Mineral complete fertilizers such as "Blaukorn" differ fundamentally from organic complete fertilizers in terms of their origin and composition.
Mineral fertilizers are available in dissolved form as liquid fertilizer and in solid form as fertilizer s alt. Coated fertilizer s alts are in the form of small globules and their coating gives them special properties such as a long-lasting effect or an on-demand release.
Organic complete fertilizers are composed of various substances of plant and animal origin whose nutrient content is known. They contain the nutrients "packaged" in a natural shell. For onehe althy home garden without unnecessary chemicals, organic complete fertilizers are clearly preferable.
Organic-mineral complete fertilizers are mixtures of fertilizers from both categories. These mixtures should skilfully exploit and combine the special properties of their individual components.
After this brief explanation, we will now introduce you to some well-known complete fertilizers.
Blaukorn by Compo-Expert: 12 - 8 - 16 (+3)
Blaukorn is a well-known complete fertilizer that has been on the market for many years. It is mostly rejected by ecologically oriented gardeners. With no organic matter and ready availability, long-term soil damage and even short-term crop damage are more likely than organic alternatives. Price: 25 kg costs about 30 euros.
Plantura organic universal fertilizer: 6 - 4 - 4 (+0, +2)
We developed our Plantura organic universal fertilizer with great care. Due to the high proportion of organic matter, it promotes soil life and is even free of animal ingredients. In addition to nitrogen, phosphorus and potassium, it also contains sulfur and sodium. The potassium content is quite high for an organic fertilizer, so it lives up to its name "universal fertilizer" very well. Price: 1.5 kg costs about 15 euros.
Manna Special Garden Fertilizer: 7 - 5 - 9 (+Mg, +S)
This combined garden fertilizer has a high potassium content, which makes it a good addition to a purely organic fertilizer. Various nitrogen compounds are included, so the mixture is designed to release nutrients both quickly and effectively. According to the manufacturer, the release depends on the temperature, humidity and activity of soil life. Price: 20 kg costs about 40 euros.
Cuxin DCM liquid fertilizer for indoor plants (mineral liquid fertiliser): 6 - 4 - 7
Cuxin's liquid fertilizer for indoor plants contains quite a lot of nitrogen and potassium. Like all liquid fertilizers, it is intended for regular use over the irrigation water. It makes sense to use an organic fertilizer in addition to this liquid fertilizer, since the liquid fertilizer lacks the long-term effect and does not contain all the macronutrients or trace elements. Price: 800 ml costs between around 14 euros and makes 250 lIrrigation water.
Advantages and disadvantages of complete fertilizers
Anyone who has made it to this point knows at least one thing: complete fertilizers are almost never real all-rounders. Especially if they only meet the minimum requirement to bear this name, i.e. contain N, P and K. Because organic and mineral compound fertilizers differ so much, the advantages and disadvantages are mentioned separately here.
| Advantages | Cons | |
|---|---|---|
| Mineral fertilizers | Fast Casting Speed | Inferior products are often released too quickly; the result can be plant damage, leaching and outgassing of nutrients |
| With coating also long-term effect | Long-term effect not a matter of course, only for an extra charge | |
| High nutrient concentration | Damage to soil structure and life if used alone | |
| Low Price | Harmful to the environment through the extraction of raw materials | |
| Organic Complete Fertilizers | Easy to use with no risk of overfeeding | Some slow release products only |
| Improve soil structure and soil life | Many products with low potassium levels, so that potassium has to be fertilized separately | |
| Natural long-term effect | Slightly more expensive | |
| Use of renewable resources | Sometimes unpleasant odor if animal raw materials were used | |
| Also available as liquid fertilizer | ||
| Also available vegan | ||
| Often contain other important nutrients |
Application of complete fertilizers
Here you will find some general key points for the correct use of complete fertilizers:
- Even if a fertilizer with N, P and K can be called a "complete fertilizer", a supply of just these three nutrients is not enough
- Even if a complete mineral fertilizer contained all 14 nutrients, using it alone would have a negative impact on the fertilized soil
- Compound fertilizers never contain all the nutrients, as there are some that should not be mixed for various reasons
- Many garden soils contain large amounts of macro andtrace sewing elements. If these substances are not replenished, however, they will become depleted in the long run
- You should therefore fertilize organically every year and bring in as much organic matter as possible, for example clippings from beds, lawn clippings or compost
- Never dose mineral fertilizers higher than the application recommendation prescribes in order to avoid plant and soil damage
- Do not fertilize a lot of mineral nitrogen in autumn, as it is very likely to be leached into the groundwater or released into the atmosphere as ammonia or nitrous oxide
Tip: Do not use compound fertilizers in combination with lime, as this leads to the formation of ammonia and water-insoluble phosphate. You should therefore fertilize lime (calcium) separately at intervals of a few months.
We have compiled detailed application recommendations for lawn fertilization or fertilizing fruit trees for you here.