I was at Lowes and I saw some CFL's that were 6400k and they were mad cheap like 30watt bulbs like $3.50 gave out like 2000lumens. And saw the 6500k 65watt was around $24 it gave out like 3500lumens . My question is will the 6400k cfl's work well for vegetating or are the 6500k that much better...