For Heaven's Sake BE CAREFUL with Spanish moss. I grew up with the stuff in Florida. If you get it off the trees it will probably be full of chiggers!!!!! itchy, itchy, itchy. If you use it--just use the sterilized kind, don't be tempted to bring a bunch back from your vacation in Florida!!! By the way, if anyone needs a really good water retaining mulch (especially if the pot is too full and regular mulch keeps washing out) use your old liners from hanging baskets. They probably ought to be put in boiling water first to kill any "uggies" in 'em but boy does this material hold the water in--I find it very useful. Betsy

One Caution---I used pretty river rocks, glass marbles and all sorts of things like that when I first started my containers. Worked well.....BUT! Turned out I needed to MOVE those containers places. Gee--as soon as you put them on the dolly and tip them up--surprise the rocks/marbles etc. fall out all over the yard. DH was throwing them up with the lawnmower all over the place. Injury was possible, but ears suffered more with the LANGUAGE! I had to give up and go to cedar mulch and there are colored pieces of glass and river rocks all over the yard now no matter how much I pick up. (I really went for it that first year and besides I think they breed). If you have to tilt a container to move it or for other reasons--take the rocks off first or just don't use 'em. Betsy

The source of my beliefs is research, practical experience, and observation. The application is borrowed from the science of geology, but physical laws of adhesion, cohesion, and gravity combine in container soils to govern its variable effect. The primary influence is the particulate size of container soils. You can prove its (PWT) existence in myriad ways. Hold a saturated sponge with its largest (in area) surface horizontal until it stops draining. Turn the sponge so it's smallest surface is horizontal, and more perched water will drain as the height of the PWT equalizes in a lesser volume of sponge. Grasping the sponge by a corner after it has again stopped draining, so one corner is down, further reduces the volume of sponge occupied by perched water and even more water will drain. Finally, with a corner down and no draining occurring, touch the corner with a toothpick held vertically (a wick) and even more water will drain. Or: Hold a toothpick to the drain hole of a container of saturated soil that has just stopped draining & watch its wicking effect drain more water that had obviously perched in the container. If you care for more details of how it all works, follow the link provided. Al Here is a link that might be useful: More information

18 gallons is about 2.5 cu ft. Ground up forest products (trees) is considerably different than conifer bark of the same size, and 'rich/dark' more often than not offers problems, rather than benefits when it comes to container media. While I'd stop short of saying it probably won't work well, I'll say that the odds are probably not good, but then you never know until you try. I would suggest getting some of this mulch and trying it in a soil you think might be appropriate for containers (soon) so you have an idea if it will work next year. If it doesn't appear as though it's going to work, you could leisurely inquire about other soil ingredients over the winter. What would you be using the granite sand/decomposed granite for? - for nutrients or as part of a soil's structure? Al