I was growing my seedlings under a 1000w light dimmed down to 600w. But it would seem even with the dimmed bulb this is too much light for seedlings. My method for figuring out how much light is too much is the forearm method. I put my forearm palm side up under the light at plant height. If I can feel any discomfort from the light its too much for the plants as well. Well I did not feel much so figured it was fine.. But too much light can hinder them and may be affecting their slow growth. I used a smart phone app that measures light, and seems they were still getting too much. Once they get bigger they can handle and thrive in the full intensity of the 1000w bulb. But for now it would seem I need to swap out my more powerful bulb for a less powerful one.
Keeping the light far away from the plants was not enough, as the light is so bright it was over the “lux limit” for seedlings. Pushing close to 14k LUX was too much. I used a smart phone app to find out how much light was being emitted.
So even with the ballast turned all the way down this was too much light, I could not raise my light any higher. So it was time to swap out the metal halide bulb for a lower wattage MH bulb.
Honestly last time I started my seedlings I think I indeed had the 600w bulb inside. But I was thinking I could dim my 1000W until they were ready, not the case it would seem. Also dimming the light seemed to shift the color spectrum, so maybe they were not getting the correct rays of light.
To remove the bulb I first have to take off the glass panel. This keeps the grow tent cooler and helps air pass through the hood without dumping into the grow tent. I cleaned the glass really good before putting it back.
Handling these bulbs require much care.. They are fragile, and if dropped can burst.. Sending glass everywhere. And if you get any kind of oil on the bulbs it can damage them as well. So handling them requires using a towel or gloves. And wear safety glasses in case you drop it.
I can see why many people just go with LED lighting. Once I burn out my bulbs I will probably upgrade to them.
Might be able to get the hood up a little higher if I ziptie the pulley connectors to the frame of the grow tent.
With the new bulb installed and the glass put back in the hood its time to turn everything back on.
Hopefully my seedlings will grow better. They no longer have the gnat problem they once had. And I am watering them way less, but seems the light may have also been hindering them.
With the 600w bulb installed and not dimmed the light seems much more balanced. Not a shift to blue as it was when I dimmed the 1000w bulb.
Once the plants grow bigger I will swap back to the 1000w to maximize their potential.
Hopefully the ones started yellowing will recover..
And testing with the new light I am pretty close to the limit already. So I will need to get that light a little higher in the tent I think. But at least its about half the intensity as it was before. Much closer to what it should be for seedlings.
