Concrete slabs cost about $2 each, and any advice that says you have to dig down further is wrong if you are in a zone 8 climate. When you move you can put them on craigslist and maybe recoup at least part of your money. But it might also turn out nice enough to leave for a future tenant. What you are thinking with the pallets sounds like a confounded mess, to be honest, and doesn't sound like any avoidance of digging. Levelling beams in trenches is a nightmare (trust me, I've done it), especially if you're digging among tree roots. Adding plastic, or rock, will just escalate the cost, escalate the mess, and quadruple the work. And if you have to remove it before moving, you will have a disposal problem. If you must work with pallets (and I have done so, a lot), your best design option is a floating deck. The thread with pictures of one has fallen off the bottom of the forum, but basically it is a flat wood deck - 2x4 boards across 2x4s or 4x4s - levelled on concrete slabs. You can make one big deck, or use the idea of making several tiles. You are right to think about just taking the pallets apart and using them as lumber, for several reasons but also that their size may not be right for you. I doubt that the 1x4 boards from the pallets will not be strong enough to hold the point force of a chair or table leg. You'd maybe have to collect 2x4s or double up the surface. KarinL

I have a flagstone walkway laid on sand, and have experimented with just about every groundcover offered. I've found woolly thyme is the most foolproof and vigorous of all the things I've tried. I think part of your problem is that the flagstones were set on mortar. With our hot summers, the groundcover needs to get it's roots underneath the cool rock to survive, and you've prevented that from being able to happen. With just the small crack to grow in, I think the plants are having a hard time. Dicondra would not be happy with that degree of reflected heat from the stones and would do poorly in the full sun areas. It might survive in part shade with copious amounts of water. It does get attacked by flea beetles here though, and rarely looks as nice as it does in the bay area.

We have plants between our flagstones and I wish we had put gravel instead. I've tried numerous types of plants/ground covers and nothing so far has worked really well. It is hard to keep watered, weeds proliferate, some plants will grow for a while and then die out. Thyme does well but some of it gets taller than what I want. It is high maintenance and if I had to do it over I wouldn't.

Thanks for the heads up...something I can try come spring!