what light are you budding them under? a 1000w hps i'd say a pound or so but its really impossible to even get a good guess my buddy just did 8, about 3 footers with his 1000w hps and got about a pound and a half.but he's done a few sets now, so he's got a little more experience. he also said the 2 right under the light had as much as the 6 others combined thats why i will be running 2 1000w hps very soon..