onion plant bulb?
EDIT: oops duhh.... T5HO are the best. Try to get pink tinted ones. It should say what they are best for...
Most people try for about 3 Watts Per Gallon, but with T5 HO it is less than that, because they are more efficient. 1-2 WPG might be enough, maybe WYLDFYA or some other magic guru might be able to give a better number. If you use low light plants like java fern and anubias then there is no need for additional CO2. They will grow extremely slow but will survive. In general planted tanks are ridiculously expensive... unless you stick with low light - low tech... OR DIY. I am going to sink in $600 into my new setup, including the aquarium... :O
Stay safe and use popular planted tank fishes,(small characin, gourami, small cyprinids, Ram, discus, angel and Ottos) cichlids are indeed dangerous to plants. ALSO don't pick tinfoil barb, or goldfish, and some plecos can be dangerous.