Luffas are easy to grow on a trellis. I used to grow luffas when I lived in California and I had so many I would take them to work and give them away. I tried it here in Nebraska, starting them in the ground about April 15. It took them a few weeks to really take off but once it had warmed up they grew like crazy. I had literally dozens of large, still green luffas on the vines when the first frost came, so they didn't get the chance to mature properly. Found out the hard way that luffas require a growing season of about 6-7 months and shorter than that just won't work.