I am a first timer grower, so please help me. I just purchased a 150 Watt greenhouse HPS white grow light. I’m planning on using it in a closet 8ft tall, 5ft wide n 2ft depth. I’m only planning on growing 3/4 plants. Did I purchase the right light n watts bulb? Will this be enough to use for my entire grow? I have a feeling I purchased the wrong light. 
Also, Will a higher watt bulb work or do I need to buy a whole new setup? I bought ILGM self flowering AK-47, do I need to prune and trim them? I think I read in someone’s post not too.
Thanks in advance for your help, your only a first timer once.
I can answer the autoflower question! Don’t prune them 
About the most you will want to do is some low stress training like tying branches down. This is due to their shortened vegetation cycle, they won’t have time to recover from snipping. As for the light, someone else should have a better idea on that. I run a 600w high intensity light in my 4x4x8ft grow tent and it has been working great. What I can say is that if you need a bigger light you will more than likely need to get an all new ballast and bulb. Mine is dimmable, but only between 600w and 400w. You can run a 600w bulb at 400w but I have read that it isn’t ideal.
Thank you. I am returning my light for a 600w adjustable hps light. Any other tips for a newbie are always greatly appreciated.
JTheH, is right and I agree. But you didn’t say what stage your plants are in. It makes a big different. I have a complete write up that MacGyver wrote on lights.
I would be more than happy to send it over to ya and you can copy and paste it for future reference
Very informative.
B Safe
Will
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Yes, about 50 watts per square foot is the horticultural industry standard for HID lighting. At 5 feet wide and 2 feet deep, you have 10 square feet, and so you’ll need about 500 watts. However, I’m pretty sure a 400 watt HPS would do just fine in that size area.
~MacG
Yes please send that to me. I have been away so I just started germinating my seeds yesterday. Does it also cover HPS n MH which to use first. I have both 600watt. I thought I use the HPS first for vegatative n MH for flowering
You should sit back and read forum posts, so many answers to questions you don’t have yet.
If you like growing, you might like reading about it. If it doesn’t kill you, it will only make you smarter.
I think you have it backwards, generally you use blue-er light for veg, which would be the MH, and then redder light for flower which would be the HPS.
~MacG