First application
Nitrogen, phosphate and potash fertilizers before planting
The basic supply of nitrogen differs by the type of planting. With direct sowing, the rule is to apply 60kg N/ha before sowing. When planting outdoors, application should be set higher at 100kg N/ha as the plant's immediate nitrogen requirement is already significantly higher at this stage. For early planting under fleece, basic fertilization of 150-60kg N/ha is usual.
In well supplied soils 60-90kg P2O5 /ha are applied, depending on the yield level. Compared to other crops, cabbage require relatively little phosphate amounts. In addition, potash fertilization varies strongly between 230-350 K2O /ha due to large yield differences and is likewise split at high amounts into 2 applications.
It is best to use NPK-fertilizer at first application. The current sulphur requirement would be met at the same time.
Second (and third) application
When N-fertilization is based on Nmin results, the correct time for sampling is in the 6-8 leaf stage (after singulation) at a depth of 0-60cm. The amount of nitrogen still missing (nominal value - basic fertilization - N min ) is applied in 2 steps when the total requirement is more than 100 kg N/ha. Stocks have to be dry when this is done. Special attention should be paid to the use of nitrogen in the form of cyanamid, which should not be applied either shortly before or after application of herbicides. The best time for the two top dressings is shortly after separation and about 3 weeks later.
Supplementing boron with liquid fertilization
As a rule, 200g boron/ha are applied in liquid form with a high amount of water, avoiding any application on very hot days. Whenever leaf-stem cross-cracks indicate a deficiency, the application should be repeated after 1-2 weeks. Dryness and/or by pH values above 7 increase the risk of deficiency.
