I have bought these packages as well from Walmart and Petco and they seem to work under pretty much any lighting. I had some sprout in a less than 1 wpg. And I seen that David mentioned that he just bought a new package after some didn't sprout, well I bought one pkg and none sprouted and there was about 5 bulbs in it and I sent them in as non sprouters and they sent me over 10 bulbs back and most had already started sprouting in the bag. Well worth sending them back.
