Outdoor container growing question

Helping my friend with her outdoor container grow and we are running into an issue with needing to water as often as three times day.

Using Ocean Forest, and everything is in ten gallon pots on cement. We painted the pots flat white, figuring they wouldn't absorb as much heat as the original black color, and the outside of the pots do not get that hot. It's normally in the 90's to low 100's in the summer here, never had issues before.

Is there something that can be put over the topsoil to help things stay dry longer without fucking up things? If no one is around to dreNch them at least twice a day, they will shrivel, and die.

One difference in her grow this year from years past is the plants were always put in ten gallons late June or early July, and on the hottest days may have needed two waterings. This year the availability of clones was iffy, so when she found some first of April she snagged them...so at least a month earlier from years past. Had to pop into ten gallons end of may because they overgrew the containers they were in.

The obvious answer would be bigger pots. But this month or next month, the local electric utility company will be coming by to trim trees branches in the back yard away from power lines. Ten gallons can be hauled inside in a pinch, a pain but doable. Any bigger would be near impossible. And unless they come in the next few weeks, we are thinking transplanting after flowering begins could be harmful, and likely wouldn't help sice the root system probably won't grow any more at that point.

Any tips or advice? She is legal, so the main concern is the tree trimmers seeing the plants and coming back later to rip it

Suggestions; place saucers/trays, something to catch the runoff. Then the plants will wick the water from below. I took piece of mylar I had around and taped it to the top of my black container, just draping it. You should also raise the pots off the concrete with bricks, 2X4's, anything. Mulch, as already suggested, is essential too for hot climates.