Blaukorn is a purely mineral fertilizer, an artificial fertilizer. There is nothing natural in it. It contains nitrogen (N), phosphate (P) and potash (K) in a water-soluble form and is a so-called NPK fertilizer. It is very good that the nutrients are immediately available. The bad thing is that it contains no organic material, i.e. no material for humus formation and no food for soil organisms. Blue grain and other mineral, so-called complete fertilizers, were the ultimate in our gardens for a long time. The result of this is that the soil is often oversupplied with the nutrients phosphate and potash.

varieties and prices

There are numerous different blue fertilizers on offer. The prices often depend on the brand and, of course, on the packaging size.

Compo Entec classic or expert, Manna Complesal, Beckmann blue fertilizer, Gärtner’s blue fertilizer, Bellandris blue fertilizer and many more. The composition is sometimes quite different. You always have to check whether the product at hand has the right one.

  • 3 kg – ca. 5 buses 7 euros
  • 15 kg – 20 to 30 euros
  • As always, branded products are more expensive than no-name products


  • Anyone who owns an old electric coffee grinder and no longer needs it can finely grind blue grain. Then you can add this powder to the irrigation water. Put a heaping tablespoon in a 10 liter pot. The risk of over-fertilization is somewhat reduced. If you are unsure, start with a little less blue grain powder. This variant is well suited for indoor or container plants.
  • Many professionals recommend watering the soil sufficiently before administering blueseed. Then again afterwards.
  • A new development for blue grain is the so-called Entec blue grain. Usually not much more expensive commercially, but improves the even delivery of nutrients.


The problem is that mineral fertilizers, including blue grain, often lead to over-fertilization of the soil. This is very disadvantageous. If there is too much nitrogen, it is not absorbed by the plants, but enters the groundwater as nitrate. Without any organic addition, soil life and soil structure will be permanently damaged. However, both are of crucial importance for a productive and healthy soil. Soil creatures responsible for keeping the soil healthy feed on organic matter. Together with mineral soil components, they convert it into humus. Humus is important for the soil.

Why is blue grain blue?

That’s an interesting question, but nobody could really answer it for me. I read on a forum that birds cannot recognize blue as a color and therefore do not pick up the grains. That’s probably why slug pellets are blue. I can’t really believe that, because there are also green granules and different colored fertilizer granules.

Benefits of Blue Grain

  • Works very quickly
  • Inexpensive compared to other fertilizers
  • Quick and easy to use
  • High proportion of nutrients in relation to the amount of salt applied

Disadvantages of blue grain

  • Soil is often overfertilized
  • Nitrogen enters the groundwater as nitrate
  • Soil life suffers
  • Soil structure suffers
  • Soil organisms die, which greatly reduces soil fertility.
  • Declining returns over the long term
  • Not suitable for pot plants – over-fertilization occurs quickly
  • Too many mineral salts accumulate in the soil. These can only be broken down poorly or not at all.
  • Plants that require rather poor soil and only minimal fertilizer shoot up. Leaves, flowers and fruit formation, on the other hand, are neglected. This effect becomes very clear with roses.

Blue grain in fruit and vegetable cultivation

Manufacturers and retailers are particularly fond of offering blue grain for vegetables. One should keep in mind that it is a pure chemical product. It is absorbed by the fruits or vegetables and thus ends up on our plates. There are limits on purchased goods, although we can only hope that they are met. But who controls the vegetables from the home garden that have been treated with mineral fertilizers? That’s why blue grain is out of the question for me. After all, you grow fruit and vegetables to be sure that there are no chemicals in them. I don’t care so much about size and looks, but only about health. I don’t need monster tomatoes or giant zucchini. Ultimately, however, everyone has to know for themselves what is important.


Since blue grain is cheaper than many other fertilizers, it is particularly popular on larger areas. There are alternatives, but they are usually more expensive or more labor-intensive. Blaukorn is quick and easy to spread and the fertilizer works quickly. A good alternative would be compost, but spreading over a large area takes time and the effect also takes time. However, compost is a much better solution for soil organisms and the soil as a whole. It contains phosphate, potash and trace elements, as well as lots of organic matter. There is no nitrogen, but there are pure nitrogen fertilizers and those who want to stick with natural materials can use manure, guano or Maltaflor.

Application of blue grain

Before applying blue grain or any other fertilizer in the garden, a soil sample makes sense. It can be determined how the soil is made and whether fertilization is recommended or whether it does more harm than good. Of course, you can’t do this with potted plants, that would go beyond the scope. This is certainly one reason why blue corn is not recommended for small planters.

  • Not recommended for plants in small containers.
  • Even for young plants, the fertilizer is often too harsh.
  • Distribute blueseed evenly around the plants. Note the quantity!!!
  • Work grains into the top layer.
  • Do not apply fertilizer to leaves or directly to the roots.
  • Water thoroughly after fertilizing.

The effect of blue grain

Blue grain contains nitrogen (N), phosphate (P) and potash (K) in a water-soluble form. This allows the plant roots to absorb the fertilizer very quickly. The desired effect is not long in coming. The nitrogen contained is usually already present as nitrate and can therefore be immediately absorbed by the plant and is no longer converted. The effect lasts about two weeks. Beware of over-fertilization. This leads to burns.

The phosphorus in the blue grain fertilizer promotes crumb formation. This in turn improves the air and water balance of the soil. Erosion by wind and weather and the risk of siltation decrease. Phosphorus stabilizes the soil. It also increases the energy of the plants. It is particularly good that the phosphate component forms bridges between the humus particles.

Potassium strengthens the cell tissue and makes the plant more resilient overall. Protection from the cold is particularly important. In addition, the water absorption is improved, which is important for the development of leaves, flowers and fruits.

soil sample

As already mentioned, it makes perfect sense to take a soil sample and have it examined. Here’s a brief explanation for those who don’t know what to do with it. Soil samples have long been common practice in commercial horticulture, because overfertilized soil has many pitfalls. It also makes sense for the home garden, especially if you want to grow fruit and vegetables. After examining the sample, you know what is in your soil.

Soil tests should be carried out every 3 to 5 years and in any case at the beginning of the cultivation, or before. One sample is usually not enough, you take one for each area of ​​use in the garden.

  • Use a spade or shovel to remove at least 10 points from a uniformly used area (vegetable bed, lawn, fruit trees and the like)
  • The best time is in early spring, before the start of the season, or in autumn, when the garden has come to rest.
  • The depth depends on the root depth of the plants.
  • Simply follow the recommendations of the soil analysis laboratory!
  • Place the 10 samples in a bucket and mix. Then remove 500 g and place in a labeled plastic bag.
  • Pack the package, enclose cover letter and order form
  • Send to soil testing laboratory or testing agency.
  • – form with price information

Is Blue Grain Poisonous?

Of course, blue grain must not be consumed, neither by humans nor by animals. Our pets are a particular problem. They are very clean and care for their fur and paws by licking them. This is how blue grain gets into the dog or cat. This is bad. However, not all blue grain is the same. There are quite different products. Some of these are pretty harmless. The nitrate content is reduced in it, which the groundwater will surely gratefully register. Nevertheless, caution is advised. There is still plenty of phosphate in there.

Blue grain is only toxic if large amounts are ingested. But who wants to say how much is too much for their dog or cat? You can often find information about this on the packaging, under safety and application instructions.

  • Blue grain contains large amounts of nitrate. This can lead to massive irritation of the gastrointestinal mucosa. The consequences are vomiting and bloody stools.
  • Nitrate can be converted into nitrite, which in turn means that the hemoglobin in the red blood cells can no longer bind oxygen. A massive lack of oxygen can occur.
  • So, beware of children and pets!!!

Blue grain is a very controversial topic. I don’t want to rate it here because I’ve never used it myself. Personally, I prefer organic fertilizers and find pure mineral fertilizers a bit outdated. Today there are better means, combined for example, from organic and mineral components. But that is my private opinion. What is undeniable is that blue corn works quickly. So if you have a defect, it can be fixed quickly. Criminal is the application without appropriate soil analysis. You never know how much negative you are doing to the floor. This investigation is important. If it is determined that the soil can tolerate the fertilizer, then blue grain is an acceptable solution if dosed correctly. However, I would not use the fertilizer for fruit and vegetables. I’ve read about bluish tomatoes and other vegetables, among other things. So I don’t have to have that.

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