Hab sie wohl zu viel drin gehabt. Viel sonne gibts auch nicht zur zeit. Aber ich hab ja platz nach oben...
Pardon my English, but I would just like to note to new growers that cannabis likes a rather airy mixture of soil.
Using normal potting soil is fine, but it does tend to get really packed, which hampers the growth and function of the roots.
Perlite and vermiculite are good fillers to mix with potting soil when potting plants. Say put a third of perlite with the normal mix and the soil will be much more airy and light, cannabis loves that.
These are available in common supermarkets in bags of like 3l, 5l, or 10l here in Finland so I think you'd find them in Germany as well.