Hello! I am a guerilla grower myself and can definetly recommend the polymer water absoring crystals, as it was allready suggested. I use them with great success in areas where the soil gets very dry. I never water my plants, as hauling water by foot to remote areas just doesent make sense to me, it is hard enough to drag my own ass across miles of rugged hilly terrain, and watter is pretty damn heavey. So this crystals are (for me anyway) a real blessing. Although, quite expensive, they are well worth it. The difference is very noticable.
The great thing about them is also, that you apply them only once every X seasons, as they dont degrade, or do so at a very slow rate, not sure about that. Anyway I have applied them three years ago and just kept planitng in the same growing holes, and they seem to work year after year...
So this is how I go about it. I dig a grow hole, the deeper the better. I ussually go down 2 feet, but that depends on the terrain. Then I line the bottom with agro textile. I do that so that the crystals wouldnt get washed away. I dont know if it actually helps with that, but I figure it cant hurt. Then I put in some coco fibers and sprinkle the crystals over that. I use more then the manufacturer recommends. Around three ounces per grow hole, and I usually plant two plants per grow hole, which if all goes well, yield around 6 - 8 ounces per plant. So this are no monster plants, but Im happy with them.
Then I fill the hole with soil that I have previousley dug out. And I also mix in some dehydrated manure that is sold in pellet form. And thats it. My plants seem to love it, and if they are happy, I am happy
I wouldnt go any other way about it, its simple, stealthy and relatively cheap on the long run. But it pretty much depends on what you are after. If you wanna grow huge monster plants, than I think this is not going to be enough (or you would have to use ridiculous amounts, which would be to expensive, for me anyway, as I grow only for personal stash.) But for an avarage yielding plants, it works just fine.