Guerilla Soil Mix Question?

My buddy did a small guerilla grow last year successfully but had to water ever 4 days when it didn't rain. This year he wants to do it right, but it is at a very remote location where it's not possible to water that often. This area is up the hill above a waterfall and the soil holds moisture better than the area last year, but still has good drainage because of the slope.


His question is what could he add to the the soil mix to make it retain moisture as long as possible to reduce watering trips? He was thinking of adding vermiculite, perlite, coco coir, and worm castings to a good quality organic potting mix. Any suggestions?

I found a couple links on these boards the other day for products that actually absorb and retain water then very slowly release it. I believe they're small gel pellets that you mix in with the soil. I've heard good things about them.

Anyone with more info on this? I can't remember the name of it. Lemme do some searchin for you.

Here ya go.

SwellGel - The original and best water storing granules aid water efficiency and improve soil conditions

Maybe something like that?

Peat Moss

Thanks for the answers I'll be looking into the SwellGel and I didn't even think of peat moss. Anybody else got anything?