Red light is mainly needed to induce flowering, and the 6500K bulbs have comparable amounts of red to the lower temp tubes, they just have more blue, so more of your electricity is getting to the plants.
I have not tried to grow seeds in straight sand so I don't know how far development will go on just water, but I have dense planted in low nutrient mix (which said it has starter nutrients in it) and had plants stall with very small first leaves. Coir is often rinsed repeatedly to get rid of sodium so chances are good that it doesn't have much in the way of residual nutrients. I would go with a balanced fertilizer rather than the chicken manure, which will be high nitrogen, low P,K.
|