Onions are very easy to care for and don't actually need any fertilizer. If you still don't want to do without fertilizing, you should pay attention to the ingredients.© Martins Vanags - Fotolia.com Few plants are really as easy to care for as onions. You plant them and wait for the time to harvest the onions. Especially when it comes to the supply of nutrients, they are absolutely undemanding.
Onions are weak consumers. This means that they only extract very little nutrients from the soil during their growth phase. You can grow onions well on any soil, even on a lean surface, there should be no problems with growing.
However, if you still do not want to do without adding fertilizer, you should note the following:
❶ Use organic fertilizer
The general rule in the garden is to use organic fertilizers such as compost, humus, etc. So you only use the nutrients that are already in the nutrient cycle.
It is therefore sufficient for onions if you work well rotted compost into the soil in spring or autumn.
❷ Fertilizer from the trade
If you have to use a ready-made fertilizer from the trade, then it should contain very little nitrogen. The vegetables don't get nitrogen very well. It is also important to ensure that the finished fertilizer contains primarily potassium and phosphorus. Patent Kahli from Dehner, for example, is ideal.
" Tip: Carrots have a very similar need, so you can grow onions and carrots together in the garden. Since the bulbs are so undemanding and frugal, you can also plant them as a secondary crop after growing a heavy feeder.