I just purchased 3 large (approx. 16 gal.) high-density resin pots in an attempt to transfer a couple of palms from broken clay pots that weigh a million pounds. My goal is to make these guys a little more easy on my back when weather warrants that I engage in the "shuffle all the plants" game. The pots are larger than the plants need so I will have quit a bit of space that I prefer not to back fill will rock or soil.
Anyhow this brings me to two issues.
1) I once saw someone use old water bottles (w/caps on) to take up space in the bottom of a planter. I am trying to go for something like that, "outside the box". Styrofoam blocks or peanuts? Any ideas?
2) Considering I live in the desert I don't have to worry about freezing temps too often. Do you think that filling the bottom voids of the planter with an alternative material like water bottles (or whatever other suggestions I get) will make the plants more or less vulnerable to damage during cold weather? In other words will I have to shuffle more often...in which case it might worth just using gravel ;-)