Home / FAQ’s - http://www.pacificlightconcepts.com/faqs/ Q: What size area does the CX300 cover? A: The CX300 emits 720 PPF. For high light intensity vegetables, flowers, and medicinal herbs, a 3’x3’ to 3.5’x3.5’ flower/bloom footprint is ideal as a standalone fixture and provides 630-865PPFD average for optimal growth rates.
Better to decide on photon density (PPFD) and work back from there. There's such a big efficiency spread in the available options that it's difficult to talk about things any more in terms of wattage.
If your space is 3ft or a meter high I would also consider DIY using many low powered emitters. A good design will take up only a few inches of head space and plants will be able to grow within a couple inches of the light.
i've got a 4x2x5 with 2 300w marshydro led. the girls seem to love it. temps have never been over 77. a previous grow had 4 of those 300w in a 3x3. got a bit warm, but gave good results
If that was my space i would diy or hit someone up with a light that utilizes Stella lenses. Contact @JimmyIndica for tips or a possible unit if he has them available.