Larry,
Depending on what you are container growing:
1. I would put bricks or rocks in bottom of tubs before adding soil.
2. I wouldn't grow anything too tall or vining with trellis support as this will
act as a sail in high wind.
3. I would use moisture retaining soil mixes, as things dry out very quickly in containers, rendering the containers fairly weightless.
4. Grow things that are drought resistant, unless you plan to install a small drip system.

Me $0.05 worth, Jeanie

I was gonna say bricks, also. Or, maybe you can get a heavy planter? I have a large planter I got from Sam's a couple years ago. We did not put bricks in it, but some heavy clay-ey type dirt in the very bottom and filled the rest with potting soil. I haven't had any problems with drainage, but then again, it was really hot and dry last year. Filled with that clay stuff and potting soil, The wind has not moved that pot yet, but sometimes the dirt starts blowing out so I need to keep an eye on whatever is planted there to make sure the roots stay covered.

If you can find tubs in 20+ gallon size, go for them, although the 15+ gallon size is easier to find. The tubs seem to be made smaller these days. UV light resistance is a plus, too. Ugly though they be, my next containers may well be rubbermaid rectangular containers because of the larger volume available, the uv resistant plastic, and the possibility their center of gravity is lower to the ground than the center of gravity of the tubs. You can even use the box lid as a planter saucer most times so the water doesn't run off quite so easy!

Moisture control granules in the potting mix if possible are helpful, mulch on top of the potting mix as the season gets hot and dry is also helpful. Some sort of drip irrigation would be very nice, maybe a water barrel on the skid with lines leading out? Depending on what you grow and in which sun conditions, you may have to water once or twice a day for the duration once the heat hits and the plants get bigger. Haven't dealt with the wind issue, because our yard is fenced and that knocks off the wind a good bit where the tubs of plants are. Maybe weight in the bottom of the container or attach the pots, trellis, and skid to stakes in the ground? Teepee or concrete wire cage set deep into the container for trellis? Have a set of stakes in each of your prospective locations so all you have to do is unhook the stake attachments, move the skid, and rehook the skid-stake attachments in the new location?

I haven't dealt with wind, so have been able to leave the container and potting mix light, deliberately, which is a plus since I sometimes haul the tubs into the house in the winter. My trellis is attached to an old swingset frame for summer tall stuff.

The Pluggers cartoon once had a panel that stated "A plugger's automatic watering system is a disgruntled teenager with a hose." The need for water, water, water is all too true. On the other hand, it has been easy to use measured amounts of water to the tubs.

ymmv.

Thanks to all of you for the good Ideas. This will be primarily a project for my wife, she may tire of it quickly. I will be trying to grow plants in the garden, I hope to be smart enough to just shut off the water if it gets like last year. Maybe we can drag my wife's plants to the shade when it gets too hot.

Larry

Larry,
I use the larger molasses/feed tubs. They hold 25/30 gallons depending on which size of tub the farmer/rancher buys. I have a "little" wind here. And have never had one blow over. I don't add anything. By the time I get them filled with potting mix and wet they are heavy to move. I do have to stake or cage the plants in the tubs once in a while. I move mine closer to the trees where they have afternoon shade during the heat of the summer and that really helps. I bought a square what I call a furniture mover at an auction that works well to move the tubs. It is approx 2 ft square. Have heavy commercial wheels on it. And a long handle. I can put a tub on it and pull it fairly easy. Sure I could pull it with my mower also if I desired. Jay

Jay, what is the diameter of the wheels on your mover? I have some we use in the house but I expect my wheels will bogg down outside. I have not done any measuring yet but I hope 3 tubs will fit on 6' dog-eared fencing. I dont know how many my lawn mower will pull but expect one 3 tub skid will be about max. The days of lifting have pasted for both me and my wife.

Larry

Larry,
Actually the one I use the most is an angle iron frame and built for shop use. I stated furniture use as I felt more would know what I was talking about. I'm not sure of the diameter. I will look but they are a larger diameter than those found on most of the similar types used in the house. These could bog down in real soft soil but work ok where it is firm or packed. Jay

Last Year I Put my container pots along the deck railing and as the tomatoes grew I just lashed them to the deck rails. No blowing over in the wind.