Purple Power Outdoor Grow in England or Ireland

Hello everyone im outdoor growing purple power they are out just over a week now in compost mixed with about 20% perlite and in home made greenhouses (2 liter coke bottles) . Anyone with any info about watering feedin anything at all it would be most helpfully.

You can feed once a week at full strength if the pots are big or twice a week at half strength. Good luck