Your post is a little confusing. Is your patio concrete or aggregate(gravel)? If gravel it would allow the water to drain to the soil and be no problem, if concrete it will surely stain it. The only solution I see is to place a plastic or rubber mat under it, and slightly raise the container so it will drain. The water on the mat will evaporate. Calistoga Al

I had to scroll up to see where i was. Is trex considered organic? Are they still playing that card? What percentage of the factory misc ingredients is actually recycled. What is the long term breakdown? I'm asking because i don't really know. I've not really followed but it seems most are not happy with it and now replacing it? It looks fake. Right behind the plastic tool shed, next to the plastic turtle sand box. And little tykes plastic jungle gym, behind the vinyl siding on the house with a plastic bubbly mailbox. Above ground plastic pool behind a chain-link with plastic strips in green and white with plastic adirondack chairs blown by the wind in a heap stuck in a corner...a storm last year. (an unfortunate driving direction landmark for visitors... just pass the elementary school, pass the 'plastic house', "its for sale!", on the left....) Plastics are difficult to avoid. Recycling is certainly the way to look at things available for free. Not sure if i would support purchasing such a thing. It would give me a bit of a shudder having a plastic or composite man-made material in my garden. If heading for a land-fill i might consider a compost bin. Maybe a flower bed edging somewhere. Base for a potting bench? I do have a compost bin made out of cinder blocks that were piled in the field when i bought the farm. Its the bin i don't really use. Just a place to stack all the big stuff i have no place for. Next to a big rusty vintage manure spreader that gets the really big stuff.

You might put an ad in your local paper or swap shop publication - for the free fill concrete - "break and take" so to speak - you never know who might need some filler for something....never hurts to put your request out there! We have a paper called The Peddler and I have never ceased to be amazed at what I can sell in it. I am no expert like most of the people who are answering you, but it would be a shame to haul in all that soil [I just got finished hauling great soil in for several beds] and have it to not work. The only other suggestion I could make is for someone with a jackhammer to come in and punch lots of holes for drainage in the slab. But that still might not work. Or....make a patio out of the slab and cut some trees.......Were it me, I would put out a "free" ad first - if that didnt work, get bids on taking it out. Then do the bed. My dad taught me something that has always served me well - do it right the first time, then you dont have to redo. After just finishing hauling all that dirt [and more to come for some new beds] I would certainly not want to do that unless I knew the bed would work. Good luck! Where there is a will, theres a way! Judith

River rock of various sizes is attractive. I have used it in several situations, but never on a high traffic surface. If not cemented: Preparation is important. Placed on dirt, stones will gradually sink into the ground. Weeds will then grow into area. So need to prepare with heavy duty landscaping cloth as a minimum. Ideally, compressed sand/crushed granite bed similar to what is used for laying patio stones. Two downsides: 1) stones tend to move around. Smaller stones much more so than larger. But large stone make a difficult walking surface. 2) Leaves and debris tend to get between the stones and can be a pain to get out. More a problem with larger stones. For 6-8" stones, a leaf blower is a necessity if you have leaves, pine needles or other plant debris in the area. Smaller stones easier to keep clean, but more likely to blow around with leaf blower or just move with traffic. If topping cemented surface: Attractive look (very small stones only)--I have it on front steps. Hard to shovel if it snows due to uneven surface. Can clean with pressure washer or leaf blower otherwise.