Transperation is increased with low humidity, air flow over the stoma (disperses water, kind of like us peeing but more holes), heat and silver excites electrons which helps as well. Magnitite ore was first seen used in Roman aquaducts as lower polarity promotes health of animals and plants alike. As far as the bulb goes a Metal Halide or Multivapor would be best, (same thing pretty much). Do you have a meter?