Like all living things, plants need food to grow and to gain energy for their metabolism. They absorb three of the most important nutrients, namely carbon, hydrogen and oxygen, as gases from the air or as components of water from the soil. But they also need a whole range of other nutrients that we have to supply them with.
Sufficient nutrients in the soil are the be-all and end-all for a high crop yield
The most important rules when fertilizing
Almost all plant nutrients are in the soil, but by harvesting and removing the plant remains, the gardener also removes the nutrients bound in it, so that the soil reserves are gradually emptied. The purpose of fertilization is therefore to replenish the soil reserves in a targeted manner.
Adapt fertilization to the plant species
Basically, garden plants (and thus also vegetable plants) are divided into heavy feeders, medium feeders and weak feeders. This distinction tells you how many nutrients a plant needs. Preferably use organic or organo-mineral complete fertilizers, which you prepare for heavy consumers according to the manufacturer's dosage, for medium consumers in half the dose and for weak consumers in a quarter of the dose. Avoid over-fertilizing the soil, because on the one hand phosphates and co. accumulate in the soil - and on the other hand over-fertilization as well as malnutrition can lead to growth disorders and an increased susceptibility to diseases and pest infestation. In addition, typical over-fertilization diseases can occur, which ultimately reduce the yield.
Which vegetables need how much fertilizer?
The table below shows which vegetables require a lot of fertilizer and which need little. If you fertilize your garden with compost, the additionally used complete fertilizer for heavy and medium consumers should be reduced by half. In this case, weak eaters no longer get any complete fertilizer at all. If you regularly apply two to three liters of compost per square meter in spring, you can do without the complete fertilizer altogether and instead apply up to 150 grams of horn shavings (€32.93) per square meter for heavy consumers and up to 100 grams for medium consumers.
| heavy feeder | medium eater | weak feeder |
|---|---|---|
| cucumber | Chicory | bush bean |
| potato | Chinese cabbage | pea |
| cabbage | strawberry | Lamb's lettuce |
| pumpkin | fennel | herbs |
| paprika | carrots | cress |
| rhubarb | garlic | purslane |
| celery | Kohlrabi | radish |
| tomato | chard | turnip |
| zucchini | parsnip | |
| sweetcorn | Parsely | |
| leek | ||
| radish | ||
| Beetroot | ||
| salads | ||
| spinach |
Lime the vegetable garden properly
Very few gardeners know the exact pH value of their garden soil. However, the soil should be limed occasionally, and this is done with regular compost use according to this scheme: Spread a slow-acting lime fertilizer (€9.70) every two to three years in early autumn according to the manufacturer's dosage instructions. If in doubt, the dosage should be slightly lower.
Have your garden soil examined
Basically, it is a good idea to have the soil examined by a specialist laboratory about every four years and then get tips for soil-specific fertilization. A soil test is due at the latest when the vegetable plants often show growth disturbances or lightening of the leaves or even crop failures occur with incomprehensible causes.
tips
Homemade manure from nettles and comfrey are tried and tested organic liquid fertilizers that provide the plants with nitrogen and potash quite quickly. Both also contain other nutrients and plant-strengthening compounds such as the silicic acid from the stinging nettle.