Sawdust for a garden?

We had a rocky mess on a hillside and it was also full of poison ivy and other weeds. Like you, we did not want to buy dirt (plus it would have taken way too much and I could not afford it) but we did have access to a lot of free sawdust, manure and wood chips.

What we did was:
1. We did spray the whole area hillside with Roundup
2. We collected cardboard and paper of all types (cereal boxes, used paper towels, cardboard boxes - anything paper), torn it in pieces about 10 inches by 10 inches, and tossed it all over the hillside. It did take a whole summer to cover the rocks and weeds. We just tossed it out there once a week and wet it down to keep it from blowing. We did not try to dig up rocks or anything - we just covered it all up with paper.
3. We took a pile of Locust Logs and laid them sideways to create Terrace type Beds all on the hill. And kept throwing down paper.
4. Then, we took all the sawdust, wood chips and horse manure and layered it in the beds. We put down newspaper in the bottom first, then an inch or so of sawdust, then poop, then wood chips.....and we wet it down.
5. At some point in there a neighbor told us to toss lime all over the place, which we did and then later he told us to toss 10-10-10 in there, which we also did.

All that was 6 - 7 years ago. We planted in the beds that first year and we did have good tomatoes, cucumbers, beans....and I think there were carrots too. Some areas did not grow well, probably nutrients were "off" in that area, but we just kept on adding stuff as the years went by and it still grows.

Two summers ago we added piles and piles of rotten hay to all the beds. We do NOT dig in it the beds, we just pile more stuff on it. This year we just added a layer of rotten wood chips.

Just give it a try and see what happens. Can't hurt. Like ours, maybe it will work out just fine. We enjoy our Terrace Garden and the children still remember working to create a garden out of a hillside full of rocks.

Good luck -

Remember that no matter what sawdust is used, green or black, it's primarily as an amendment to temporarily change the soil structure. It's virtually void of nutrients with barely 2# of NPK per ton. After the initial attack by fungi, there's even less left. That's why a sawdust pile may sit for years with nothing growing in it.

Old sawdust is great when mixed with manure and urine. The cells soak up that nitrogen and slowly release it as the soil bacteria breaks them down. When alone, their carbon to nitrogen ratio is about 325:1 and needs 10 times more nitrogen to break down. But if the sawdust is at the saturation point with urine, nothing else is needed to break it down sufficiently to where it is not a big danger to garden plants.

Martin