HI . I have a question, if anyone can help me. I'm building a new raised bed and have an old sawmill a mile down the road, he told me I could have all the composted saw dust I could haul away. its as black as my keyboard but I've never used old sawdust what will I need to add to it and when??? I have chickens, bunnies, horses and goats So I have lots of manure but I have to haul and dig that by hand the saw dust will be hauled and dumped. Ps I'm planning this bed for strawberrys and rasberrys.