Getting 1-2 lbs off 1 plant indoors is some serious skill and VEG time (extra power bill)- save yourself vegging that extra 2 months and grow 6-9 plants under a light, you will have a much easier time hitting a couple pounds that way.
You can get great yields running higher plant numbers of smaller plants and harvest more often or perpetually. Take lots of clones and keep multiple mothers around. To get yields like that per plant will take a very long veg time.
-Funk
To achieve high yields on a single plant typically requires a longer than usual veg as most others have pointed out. Trellising/screening plants assists with this process by multiplying the number of colas you have. But how you grow the plant is secondary to what type of light you are using.
A lot of growers these days are using white lights because they're the cheapest option available. They can grow plants just fine and give good results, but they were never designed for plants. The spectrum is not weighted properly in the 3 regions of PAR, they contain a lot of wavelengths that are inefficiently absorbed, and due to wide-angle dispersion they tend to waste a lot of energy illuminating your walls rather than making sure that all available light gets to your plants.
Since 2009 our lights have consistently delivered at least double the grams per watt of HID in independent side-by-sides (many of which were done on ICMag and you can view via the link in my signature). We have also done 3-4X the yield per watt of some competing LEDs several times over.
So if your goal is maximum yield (which mine always was) because you have a limited plant count and need to reach a certain volume, what you choose for grow lights is going to have the biggest impact on how much your plant is going to yield.
The spectrum is not weighted properly in the 3 regions of PAR, they contain a lot of wavelengths that are inefficiently absorbed, and due to wide-angle dispersion they tend to waste a lot of energy illuminating your walls rather than making sure that all available light gets to your plants.
"There is considerable misunderstanding over the effect of light quality on plant growth. Many manufacturers claim significantly increased plant growth due to light quality (spectral distribution or the ratio of the colors). A widely used estimate of the effect of light quality on photosynthesis comes from the Yield Photon Flux (YPF) curve, which indicates that orange and red photons between 600 to 630 nm can result in 20 to 30% more photosynthesis than blue or cyan photons between 400 and 540 nm (Figure 3)[3], [4]. When light quality is analyzed based on the YPF curve, HPS lamps are equal to or better than the best LED fixtures because they have a high photon output near 600 nm and a low output of blue, cyan, and green light [5].
The YPF curve, however, was developed from short-term measurements made on single leaves in low light. Over the past 30 years, numerous longer-term studies with whole plants in higher light indicate that light quality has a much smaller effect on plant growth rate than light quantity [6], [7]. Light quality, especially the fraction of blue light, has been shown to alter cell expansion rate, leaf expansion rate[8], plant height and plant shape in several species [9]–[11], but it has only a small direct effect on photosynthesis."