If you want to garden naturally and ecologically in your raised bed, you should preferably fertilize your plants with horse or cattle manure. You can get both fertilizers cheaply from the nearest farmer or the nearby riding school.
Horse manure is a good fertilizer
Horse manure contains everything plants need
Horse manure in particular is ideal for becoming part of a compost raised bed. However, you should only use the horse droppings - not the straw that comes from the boxes. This also contains urine, which is very pungent and could affect the growth of the plants. Horse manure contains all the important nutrients that your crops need: these are primarily nitrogen, phosphate, magnesium and potassium. In addition, the fertilizer binds the water in the soil (in this case in the raised bed) so that the risk of drying out is reduced. Horse manure should always be brought in as one of the middle layers when (re)placing the raised bed in autumn.
tips
If you want to fertilize your plants directly with horse manure, it is best to use composted manure rather than fresh manure.