Ok - facing a catastrophic drought here in CA. I have 12 established raised beds, and am looking for an additive that will aid in moisture retention. I have a modest compost pile - and that has been impacted by the drought as well - no grass clippings, very little garden waste, mostly kitchen waste and shredded paper.

I am looking for something to add that is both organic and will aid in water retention. all of the beds have drippers and a thick mulch, but I am still finding that the soil is drying out to a point where the water just rolls off the top rather than sinking down to the roots.

I water once a week.

any suggestions?

Much thanks in advance!!