{"id":15104,"date":"2026-03-01T09:47:53","date_gmt":"2026-03-01T08:47:53","guid":{"rendered":"https:\/\/www.substrate-ev.org\/?p=15104"},"modified":"2024-08-20T11:41:21","modified_gmt":"2024-08-20T09:41:21","slug":"fertilise-plants","status":"publish","type":"post","link":"https:\/\/www.substrate-ev.org\/en\/fertilise-plants\/","title":{"rendered":"How to fertilise plants – when, how often and with what?"},"content":{"rendered":"

Plants need nutrients to survive, just like humans and animals. If you never fertilise your plants, you are practically starving them. The consequences are reduced growth, discoloured leaves and susceptibility to pests and diseases. In the long term, plants weakened in this way can die. But fertilising plants is not that difficult!<\/strong><\/p>\n<\/div><\/div><\/div><\/div><\/div>

When do I need to fertilise my plants?<\/h3>\n<\/div>

If the plant has just been repotted or planted in fresh, high-quality potting soil<\/a><\/strong><\/span>, you do not need to fertilise it for around 4-6 weeks. An exception to this are peat-free or heavily peat-reduced potting soils, which often need to be fertilised earlier with a nitrogen-rich fertiliser. If in doubt, always follow the manufacturer’s fertiliser recommendations on the packaging.<\/p>\n

In general, high-quality potting soils are fertilised during production according to their intended use. The nutrient composition of a classic potting soil is therefore different to that of a specialised soil, e.g. for vegetables or citrus plants.<\/p>\n

You can recognise high-quality soil by the RAL quality mark for substrates for plants<\/strong>. A database in which you can search for substrates with the RAL quality mark is linked here: To the product filter<\/a><\/strong><\/span><\/p>\n

However, you should also start fertilising high-quality soil no later than 6 weeks after planting. The nutrients are then as good as used up and the plants will soon grow much more slowly. React before a nutrient deficiency occurs!<\/p>\n<\/div><\/div><\/div><\/div><\/div>

How can I recognise a nutrient deficiency in plants?<\/h3>\n<\/div>

The most important main nutrients for plants are nitrogen (N), phosphorus (P) and potassium (K). Their respective proportions in a fertiliser are usually given in this format: NPK 7-3-6 (example values). The fertiliser in our example therefore contains 7 % total nitrogen, 3 % total phosphate and 6 % total potassium oxide. Other main nutrients are magnesium (Mg), calcium (Ca) and sulphur (S).<\/p>\n

If one of these main nutrients is no longer available to the plant in sufficient quantities, the first symptoms of deficiency soon appear:<\/p>\n<\/div>