I've thought about an outdoor summer set up, I live in Ohio too so I'll be interested to see how it works for you. We have too many lightning bugs for me to work up the nerve yet. Do you plan to have a heat source? It's been a weird summer. What size are you thinking?
My rough "idea" is:
Soil substrate - fiberglass screen or landscape fabric 6-10" below the surface. Would need to buy dirt cause I'm in the city - 50/50 sand/topsoil mix (this is basically what I use in my cage) grass or clover ground cover, lots of large rocks, platforms, branches. I'd worry about the wood chip chunks getting ingested and like the burrowing/digging ability of the soil anyway. Your dragon may want a cool damp place to escape in a really hot day. The screen/fabric bottom would keep him from digging out and allow drainage too, a tarp may collect moisture and encourage mold/fungus growth. I wouldn't bother sterilizing anything that goes out in the yard honestly, it's just going to get recolonized with critters and flora anyway - some of them are pretty good helpers to help keep the mold/fungus at bay anyway.
Plants - dragon food basically. There are some edible succulents I might try too, but mostly greens (mustard, turnip, kale, collards) and edible veggies/flowers. Pepper liked pea sprouts and nasturtiums - the peas might be encouraged to grow for some shade plants as well. Maybe some mint and oregano - if grows like weeds in my garden.
