The dimension of phosphorus- and potash fertilization depends on the degree of supply of the soil and also on the requirements of the individual vegetable species.
The degree of supply can be taken from the information from the soil analysis. No soil test results available, then the amounts of fertilizer given in the last few years provide an approximate indication of the degree of supply. With correct fertilization, a medium degree of supply can be assumed. Phosphorus and potash are spread to till the soil in autumn or spring. However, no more than 20 g K/m². If the need is higher, then you give the rest along with the nitrogen top dressing. When choosing potash fertilizers, low-chloride or -free fertilizers should be chosen, because many types of vegetables are sensitive to chloride.