So hypothetically if I had seeds that germinated, and now I could see the two little cotyledons that popped, how close would I put it from a 400w HPS bulb? Is it too much light?
Hold your hand just above the plants under the light. If your hands get uncomfortable from the heat, so will your plants. That's just a general rule of thumb. I used this and it has worked out perfect. Only have been watering my plants every three to four days since sprout. I have a grow journal going if you want to check it out. Hope this helps. Peace. Please.