After doing a great deal of research, we used pea gravel in our last play area. Here's why . . . Mulch decomposses and molds and requires refilling/refreshing 1-2x/yr. Sand is frequented as a litterbox by animals and will end up being tracked inside by those playing in it. Rubber Mulches - We weren't convinced on the safety aspect of our children playing in what is basically recycled tires (although we liked the eco-friendly aspect). In the end we chose pea gravel because it is durable, alot of fun for the kids to play in (much like sand in the ability to scoop and pour without the mess), and very easy to "clean" it by just blowing lightweight leaves out with our yard blower. Although gravel doesn't seem like it would be a "soft" material it actually has an amazing amount of give and movement in the small pea-sized form. 9" of compressed (material listed below) will adequately provide safety for equipment with critical heights up to: wood mulch /10' double shredded bark/7' uniform wood chips/6' fine sand/5' coarse sand/4' fine(pea) gravel/6' medium gravel/5' We put about a foot deep of pea gravel in our space. A HUGE truckload cost us around $150 delivered.

I'll take a stab at it and hopefully the experts will come help as well. Overall the plan sounds pretty good to me. Much better than just laying down some weed and feed and hoping for magic :) My first suggestion would be to figure out what type of grass you have. Either through the internet or by digging up a clump and taking it to a local nursery (finding a good, local nursery is worth its weight in gold 10 times over!). In fact you could pull every type of weed and I'm sure your nursery could identify and suggests a solution for you! Then I would get a soil sample. You can opt for the extensive ones through your county or just buy a cheap one on amazon. This will give you a general ideal of where your at as far as soil conditions go. While your grabbing your soil sample look at your thatch build up and soil density. Always good to see if your yard just needs to be thatched and aerated so the grass can actually receive nutrients to grow! Good luck!

Being the lazy gardener I am my rule is to go with easiest path- I do have few huge oaks on the property- so all fallen leaves stay on flower beds. In the spring I only remove worst pile ups leaving everything else to work itself out. I do not only overplant I double and triple plant in same spot- gardening on suburban lot is a challenge when you want one of each plants ;) so I have early bulbs and ephemerals going in the spring, then I might grow spring blooming columbine and fall blooming anemone together in same spot, or early blooming phlox subulata and fall blooming gentian will give way to each other... I do not have weeds/ they do not stand any chance with my full garden/ and I really do not mulch- mother Nature does it for me. I do transplant/ move plants around once in a while- at worst I could kill ephemerals if I am not careful or just spread around many of my naturalized bulbs...

Borderbarb, I just recently found these forums and have been posting about what I know, which at the moment is Rubber Mulch (having done a bunch of research before a purchase a few years back and again over the past week or two before another one). I didn't even notice how old this thread was. I have just been very happy with the product I bought, and wanted to share my positive experience in posts about 'Rubber Mulch', where there seem to be a lof of uninformed negative posts. The threads in which I posted happened to be the ones that came up when I searched that topic on these forums. I cited the site where I bought mine because I like their product and because they have a lot of safety information linked from external, reputable sources, like the EPA and IPEMA. Also, the black dirt that accumulates on urban areas and near busy streets (we live a block away from a highway, so I feel your pain about black soot everywhere) is not from tire particles (though I am sure some small amount of it is). It is from the exhaust from automobiles.