The variety of cannabis fertilisers available on the market is breathtaking; watering or via foliar application. It should be noted that these are chemicals, so compatibility must be controlled. In order not to diminish their effectiveness when used, it is better to know which fertilisers cannot be mixed. Therefore, here are some tips to keep in mind when choosing fertilisers for cannabis plants. .
Solubility. Each product has a certain solubility, which is expressed in grams per litre. It indicates the maximum amount of fertiliser that can be dissolved in one litre of water. This value in turn depends on other variables, such as temperature. In general, as the temperature increases, so does the solubility, although sometimes nitrogen fertilisers react by lowering the temperature of the solution.PH. The optimum pH of the final solution is that which maximises the best absorption. In cannabis plants the pH ranges between 5.5 and 7.0, although it will depend on the type of crop and the stage. This is the right range for nutrient assimilation in order to improve the availability of nutrients. If this factor is not under control, there is a risk that fertilisers are not well-absorbed.Dosage. It will depend on the brand and type of product. Each one has a different composition, proportion and efficacy. For this reason, they usually come with cultivation tables showing the ideal doses.EC or electroconductivity is the ability of a liquid to carry electricity. In fact, it depends on the water’s mineral content. In other words, it is a measure of the amount of minerals it contains.Compatibility. Certain phytosanitary products are not able to be mixed with each other, as they are no longer assimilated by the crop and can also clog the watering system.
Fertilisers that cannot be mixed together
One of the fundamental parameters related to compatibility is fertilisers’ solubility, as the interaction between different composants can generate nteraction between different compounds can generate insoluble compounds (precipitatations), as well as causing water stress and nutrient deficiency. Among the most common incompatible interactions are:
Calcium fertilisers with sulphate fertilisers. When they are dissolved in the same tank, calcium and sulphates are released and then combine to form what is known as gypsum, with poor solubility.Phosphate fertilisers with magnesium. Magnesium can form magnesium phosphate precipitations.Calcium fertilisers with phosphate. Causes calcium phosphate precipitations.Ammonium sulphate with potassium chloride or potassium nitrate.Non-chelated micronutrients with phosphate fertilisers in some acidic media. Among the most common are iron and zinc phosphates. Micronutrients can also react with salts in the spraying water, forming poorly soluble compounds, so it is advisable to apply them in a chelated form if there are problems of poor water quality.Calcium has always been more difficult to absorb, because the plant is not able to mobilise it, causing problems and deficiencies. It is a compound that is compatible with few fertilisers. For this reason, it recommended to add chelating elements or cytokinins to facilitate absorption.
All incompatibilities are shown in this detailed table:
On the other hand, it’s important to take into account that in case of using biofertilisers, such as mycorrhizae and trichodermas, it is not advisable to use mineral fertilisers, as these could kill these micro-organisms. Likewise, you should never mix two fertilisers without dilution.
Recommendations when using fertilisers
Before starting to use fertilisers:
Check the label of the components. It indicates the specifications with those phytosanitary products that are incompatible, doses or the application period.Apply the appropriate safety measures.Ensure the proper conservation of the equipment.Follow the mixing order marked by the manufacturer.
Following this recommendations and being aware of which fertilisers cannot be mixed, possible problems in the supply of nutrients to the crop can be avoided. Therefore, it is important to check and follow the specifications of the manufacturer.