Blue grain is a popular fertilizer among amateur gardeners. It quickly provides plants with important nutrients. In the long term, however, it harms the soil and biodiversity.
What is blue grain?
Blue grain is an artificially produced fertilizer. It contains a mixture of nutrients that almost every plant needs: Nitrate, phosphate and potassium. This mixture makes blue grain a complex fertilizer.
Other names of blue grain are derived from the nutrients it contains: You can find it in stores as Nitrophoska or NPK fertilizer, in liquid form or as granules. Since the granules are often colored blue, the fertilizer is called blue grain.
How does blue grain work?
Blue grain is a mineral fertilizer. The nutrients are water soluble and immediately available. The plant can absorb them directly through its roots. Fertilizing is simple and effective:
- Nitrate contains nitrogen. Plants need the nutrient to form proteins and grow.
- Phosphorus is an important building element of DNA. Plants need it to grow.
- Potassium is important for photosynthesis and regulates the water balance of the cells.
- Many blue grain fertilizers also contain magnesium, which further strengthens the plant. This is often indicated on the packaging as 12/12/17 + 2. This means that the blue grain contains 12 percent each of nitrate and phosphorus, 17 percent potassium and 2 percent additional magnesium.
With blue grain, you can supply plants with important nutrients in the short term. In the long term, however, the artificial fertilizer has negative effects on the environment.
Blue grain: effects on the environment
NKP fertilizers contain highly concentrated nutrients. Above a certain amount, plants can no longer absorb these nutrients. They accumulate in the soil and oversaturate it. This affects plants and the environment:
- Overfertilized plants often shoot up, while flowers, leaves and fruits do not grow properly.
- Many wild plants can only survive in nutrient-poor soil. If too many nutrients are available, they are crowded out by other species. As a result, biodiversity suffers.
- Nutrients from overfertilized soils enter the groundwater. Nitrate in particular pollutes the nutrient cycle. It ends up in rivers, lakes and the oceans. The result is eutrophication of water bodies.
- Some NKP fertilizers advertise a lower phosphate content. They are somewhat more compatible for the environment – but they are not really environmentally friendly. The European Federal Environmental Agency reports that a lot of energy is needed to produce artificial fertilizers. This consumes a lot of resources and produces harmful emissions.
Artificial fertilizer also contains no organic material. However, organic material is important for the soil to remain fertile in the long term.
Caution: In large quantities, blue grain is toxic. Be sure to follow the directions on the packaging. Do not use it in places where children or animals are present.
Alternatives to blue grain
Blue grain and other chemical fertilizers have a targeted, short-term effect. But to keep your plants healthy in the long term, they need healthy soil. Chemical fertilizers do not help – they do not contain food for microorganisms in the soil. These microorganisms are important for good soil. They produce humus, which contains nutrients and loosens the soil structure.
Therefore, it is best to use organic fertilizers. These usually consist of plant waste products such as compost. The soil organisms decompose the organic fertilizer, providing for themselves and at the same time releasing nutrients for the plants. Unlike chemical fertilizers, organic fertilizers have a long-term effect and contribute to a healthy soil.