I want to create a setup to grow 20 plants indoors without sending my costs through the roof in electricity. I am living in Holland, any advice?
Organic bud from a living soil medium is the best smoke, hands down. Check out the organic section. You don't necessarily need 20 plants to get a lot of good bud either.. 60% or more of today's genetics have the potential to grow 5 pound plants. 25% about 10 lb plus. Not sure what that is in kg, but it's a lot. weights will obviously be less based on space restrictions. To increase resin production (for higher thc levels) you need to increase the amount of UVB light in your indoor grow. This can be accomplished with reptile lights, suntan lights, or (inefficiently) with metal halide lamps.
You can use induction lights or led to reduce electricity. I'm not sure if induction lights would be available in Holland... Search around for led grow lights or (even better) induction. I think you can ship some from the US from www.inda-gro.com and www.prosourceworldwide.com.... Start up cost is more than HID, but they last much longer, are more efficient, and cost less to maintain. HID bulbs and ballasts need to be changed out often and create lots of heat that needs to be vented. They use a lot more electricity to produce equal, if not less, light. Reptile lights are pretty efficient and aren't expensive. They come in several compact florescent styles like t5, t8, or regular dome-style. I highly suggest those for higher THC. A water-only soil mix is free of expensive bottle nutrients. It's a trifecta of cheapness! Sorta... Haha. I'm sure you can get your hands on some efficient grow lights one way or another.