what can I use for organic material? I
don't have compost.

OLD, well rotted horse or cow manure.
Easiest to obtain is packaged peat moss.
Some municipal & county waste management programs sell or give away compost.
If you live near a forest, you can go out & collect leaf mold from the forest
floor.
If you absolutely can't find anything else, you can use sawdust or tree
chippings. However, if it is fresh, you will have to add extra fertilizer.
Iris,
Central NY, Zone 5a, Sunset Zone 40
"If we see light at the end of the tunnel, It's the light of the oncoming
train."
Robert Lowell (1917-1977)