Hi Kathy, I'm a newbie myself, but I have a guess. If you used concrete instead of cement, your mixture was too weak to hold together. Concrete is cement mixed with other stuff. The usual "recipe" for concrete is 1 part cement to 2 parts sand and 3 parts aggregate. So when you buy concrete in the bag, the cement is already diluted 5 to 1 because it's meant to be ready to use by just adding water. Adding peat and perlite to that dilutes it even more. Since the cement is what holds everything together, that means your pieces will very lack the strength they need to last. If you buy straight Portland cement instead of concrete, you can control the proportions of your mix to keep its strength. I've been using roughly one part cement to one part each of sand, perlite, vermiculite, and peat. I haven't been at it long enough to overwinter anything yet, but so far everything's nice and strong. Hope that helps! LadyLong

NO Dirt for Tillies, they will rot. how big are those pots? Do they have drainage holes? if so just put enough gravel to set the plants in place or use a cork to attach the plant to.. The only reason for roots on Tillandsia's are to hold in place doesn't take in nourishment or water they are only used for support..basically you can use anything that doesn't hold water. cliff

Image by: fuzzy Hypertufa covered plastic pot Plastic Pot Recycling - Hypertufa-Covered Pot Member fuzzy also revamped a large (gallon size) black plastic pot: Cover the outside of the pot with chickenwire, crimp it around the rim about 2" down and around the bottom about the same amount. Next, I turn it upside down and pack hypertufa (leaving the center drainage hole) all over the bottom and sides. A day later, flip it over and cover the rim and the 2" on the inside. A day after that, use some chickenwire scraps to rough up the outside. Now that the inside is invisible (because it's filled with dirt), you'd never know it's a black nursery pot... For more information and hypertufa "recipes" be sure to check out the Garden Web Hypertufa forum

1. It should not. You do not mention what material you deck is made from. Leach extra long if there is a concern. 2. Not sure what you mean by chemistry factor ? Is this in reference to question 1? or are you asking if they will grow together, You really can plant most anything in hypertufa - it does not have to be sedum. I have large containers with Japanese maples and conifers. Another with small Hostas. Check out the container forum - Als' Gritty Mix ( potting mix) BTW - if it is below 50F in your garage in Alaska you hypertufa will not properly cure. 3. should not. I have neve notice any impact to my grass, but if there is a concern, just move the process to the driveway.