Fertilizers are used in agriculture and forestry as well as in horticulture and in your own private garden to supply plants with important nutrients such as nitrogen, phosphorus and potassium. In addition to heat, light, air and water, these play an important role in the growth phase of plants. Especially in spring and summer, people like to use powerful mineral fertilizers, as they are often inexpensive and easy to use. But which fertilizer is really considered ecological and sustainable and is the best for healthy plants?
Mineral vs. organic fertilizer
Mineral fertilizers are usually produced industrially and energy-intensively, are obtained from fossil minerals and are available as salt. It is often referred to as “artificial fertilizer” because various chemical processes are used in its production. The nutrients in mineral fertilizers are already dissolved and are therefore quickly and directly available to plants. However, the plant also uses up the nutrients very quickly. If agricultural fields are fertilized too heavily with nitrogen fertilizers, this damages the climate in the long term and also pollutes the soil and water. Over-fertilization produces nitrous oxide, which is 300 times more potent than carbon dioxide and contributes significantly to the greenhouse effect.
Organic fertilizer contains raw materials of animal or plant origin and is available for sale as liquid fertilizer or in pellet form. Well-known plant-based raw materials are organic waste and green waste, while animal-based raw materials include excrement, bone products such as horn shavings, shells and sewage sludge. In contrast to mineral fertilizers, organic fertilizers are not in the form of salt, but in the form of grown structures. These structures must first be decomposed by soil organisms so that the plants can use the fertilizer at all. In principle, organic fertilizer acts as a plant fertilizer as well as a soil fertilizer – and can therefore also improve soil properties. Organic fertilizers have the advantage of supplying the soil and plants with the necessary nutrients and promoting humus formation. Compared to mineral fertilizers, there is less risk of over-fertilization or leaching with organic fertilizers.
In general, the effect of a fertilizer always depends on its composition. The soil temperature, soil moisture and pH value also influence how the fertilizer works. When it comes to fertilizer, you should always pay attention to the specific nutritional requirements of your plants and the dosage. Because too much can also lead to over-fertilization and thus harm your plant.
Sustainable fertilization - the best fertilizers
Algae are a rather unknown but nutrient-rich organic fertilizer. These can play an important role in plant growth. When you clean your garden pond, you can use any remaining algae for this purpose.
Nettle slurry, on the other hand, is much better known among many gardeners. The rather strong-smelling liquid manure is often used both as a fertilizer and for pest control. You can find detailed instructions for making the liquid manure here.
An equally excellent fertilizer is eggshells containing lime, which are particularly suitable for flower or herb beds.
An unusual miracle cure from the kitchen is vegetable water, which, as nutrient-rich cooking water, is very suitable as a fertilizer. Broccoli, cabbage or asparagus water in particular can be used wonderfully as a liquid fertilizer.
Wood ash from the fireplace is particularly effective for tomatoes, celery and potatoes. However, you can find out exactly what you should look out for here.
Horn shavings are a pure nitrogen fertilizer. These consist largely of animal protein and are appreciated by many organic gardeners.
If you want to pay attention to sustainability and use existing resources, you can use coffee grounds as fertilizer. Mushroom growers have also sworn by this fertilizer, which is available in infinite quantities in large cities, for years as it creates a valuable breeding ground for mushrooms.
Good old compost is also well known and universally popular. If you have a garden, you can make it yourself from grass cuttings, leaves and vegetable waste from the kitchen. Humus-rich compost ensures good plant growth in the garden and also promotes soil life.
Not only coffee, but also tea and beer contain important natural nutrients for your plants. Used in moderation, old tea bags or a few sips of beer can help to grow plants and improve the soil.
For people without a garden but with enough space in their home, the worm bin is a practical, convenient and odorless alternative to the compost heap.