Can I use one light from seed to harvest?

Im planning on using a 4x4 tent with a 600w MH/HPS light with a dimmable ballast. I’m wondering if I can start a seed using the 600w MH bulb? If I moved it far away, or even if I dimmed it, would it be safe to start my seedlings under?
Also wondering if I can run veg and flower on full 600w (MH/HPS for veg/flower respectively) as Ive read that you should increase watts for flowering. Should I veg with it dimmed to 400 and then up it to 600 when I switch to flowering and change bulbs? Any advice would be appreciated!

Side Note: This forum is by far the friendliest, most knowledgeable, and most helpful group of people I have come across while researching growing. I appreciate you all, and wouldnt be confident starting this adventure without you! Thank you all!


If you have the dual ballast, you’ll want to run the mh bulb for veg and hps bulb for flower. As far as dimming, you can and probably should especially when they’re seedlings. As they begin to grow, gradually increase amount of light. It’s usually referred to as light hardening. If you gradually increase it, you should be able to get them to about full power. 400 watts would probably be suitable as well, it really comes down to the height of your light above the canopy. The higher the light is, the bigger footprint and lower intensity. So you just tinker with dimmer and heights until you get it suitable.


Yes you can man I’ve done same thing with 400ww i did not change anything but hours of light and distance between light and plants :seedling:


Ive got 4 seedlings in my tent w/MH @50% power about 14" away. They’ve been there since putting in pods. After the 4th or 5th set plan to transplant (already in pods inside cups of coir) to forever home & gradually increase light.



Well there you have it. And I agree with the three comments posted.