The ones you get at the box stores aren't really worth it. Their lumen numbers are really low compared to cfls.

id stick with cfls still at this point.

There are LED specific grow lights on the market that do well in my experience. Though they can be a bit pricey. Two vendors are California Lightworks and Mars Hydro. I have a Calinfornia Lightworks setup I bought last year. It seems to cover a 2.5' x 2.5 area well.

Household led bulbs are not powerful enough. You would need two of 10W led bulbs to match a 23W CFL. CFLs are cheap and produce decent light. The advantage of single bulbs like these is that you can position and angle them more flexibly. If you have lots of plants of various heights then this can become pretty cumbersome too. Not to mention that the plant area starts to look more industrial with many wires and fixtures.

If you want to try Led grow light - a mars hydro 300 for $70 shipped is a good starter light. It consumes about 130W, runs cool but is one of those purple lights. It will be good for about a 3x3 area of regular house plants. I have two of these and they are pretty good. Power consumption wise it is equal to about 5 23W CFLs but puts out more usable light than CFLs. In addition you can hang it 18 to 24 inches above the plant and cover a larger area.

I have UFO led lights. They range from 150 to 270 watts. I have a 12 watt led and it lights more area than my 26 watt cfl. I like not having to replace bulbs.

Betta: you will probably hate my answer but here it goes.

I really doubt that 150W UFO led light is actually consuming 150W. If you measure it it is more likely less than 100W and more like 75W. Most grow lights being sold out there are using false advertisements. They are not all that bad but do not expect the claims they make since in most cases they are just outrageous.

The mars hydro 300 I mentioned in my post above consumes 135W or so but you would think it is a 300W light from the model name. At least some where in their details they clearly state the actual consumption. And they say it is equivalent to a 150W HPS lamp and that is credible.

It is possible that 12w led may look like it is lighting a larger area, but it is not technically feasible that it can produce more light than 26W CFL. Or let me put it another way. A 12w led that can beat a 26W CFL in light output would cost about $50 if you make it yourself. Some bulb designs are meant to spread the light better and some are better at concentrating the light in a smaller area. What our eyes perceives as bright light is no where near what the plants consider bright. If you can look at the light without squinting or blinking then it is not good enough for the plants.

And another bit of false advertisement is the longevity of leds. Technically leds themselves can last a long time depending on their quality. But the associated electronic circuit will fail much earlier than that. A good quality 10w led from Cree will cost at least twice as much as one of those Ecosmart bulbs at HD. But there is a reason for that and that is robustness and reliability.

Watts isn't the only way of measuring light output, An LED produces more lumens than the same wattage of CFL.

Not true. ^

you can't make a blanket statement like that as not all LEDs are created equal. There's more junk being sold than quality LEDs.

Quality will cost you a lot more for LEDs than CFLs currently.

Betta: You are right that watts is not the only way to compare. But for all practical purposes most household leds produce about 10-15% more light (in lumens) compared to a cheap CFL for the same wattage. A good quality flourescent tube can match those household leds pretty well in lumens.

In the same vein, there is a saying in grow light community - lumens are for humans and PAR (photosynthetically active radiation) is for plants. Lumens is a measure of how human eye responds to light. PAR value is what plants care about but you cannot easily find that info. Generally speaking leds have slightly better PAR performance than flourescents for the same lumens. Cutting edge leds (very expensive) can give you 2-3 times the PAR performance for the same wattage.

Human eye is most sensitive to green light. Manufacturers use this info to tweak the lights to make it look brighter to humans. Plants on the other hand are more sensitive to the red and blue portions of the light. This is important to growers that have to balance health/productivity of plants vs cost/efficiency of light. But for most hobby growers lumens are good enough measure of amount of light.

The LEDs I use only use red, blue, and white light. I use high quality LEDs.

Best measurement is PAR DLI. Lumens and lux is okay. You can get by with a cheapo meter and it's not too bad.

I have all of the above including industrial models, they are relatively similar in measurements. You just can't expect much from cheap instruments.

Would you have any good recommendation for good enough but cheap PAR/DLI meter? I see quite a few on amazon but have not been able to select.

I use several UFO-type LED fixtures for supplemental light in the basement garden (which has T8 and T10 fixtures for multishelf plant stands). The LEDs help cover the edges of the shelves and potted plants on the floor between light stands.

I've had them for 2 1/2 seasons now and at $80-90 each they've been a good investment.

I have great success with them. I get big healthy Tomatoes.