Hell yea, 1watters will work. Check out the "7 Plants Under Astir" thread, or whatever it is called. That's all 1W diodes.
Make sure you get a good price on them, though, and try to find the largest chips you can. Do some research and then research some more. I bought 40mil Whites, 38mil Blues, 38mil Reds, etc. It's a hodgepodge of cheap Chinese stuff found on eBay. I'm only in veg right now, so take what I say with a pretty huge grain of salt, but my plant seems to really like them. I've got a couple multichip LED's in there over that plants and I really don't have to get the supplemental panels that I made with 1W chips very close at all before some of the side leaves start looking at those instead of the overhead spotlight.
Random note: What about straight up Pink LED's? Call me crazy , but check this webpage out.
http://ledmuseum.candlepower.us/ledpink.htm
Like, wtf?! Some of those look REALLY good...