I have two new beds that are 45 square feet each and dug out one foot deep. So, I need soil and compost for 90 square feet, one foot deep. Can anyone tell me the measurements for cubic feet I need?
You were already better off than I was the first time- I needed to know how much soil to buy in cubic INCHES! My beds were irregularly shaped. The guys at the landscaping place were really nice, but they probably had a good laugh after I left.
FYI, I called a couple of different experts to check on these measurements and this is what I found out. You are right, there are 27 cubic feet in a cubic yard. However, if 90 square feet, 12 inches deep were 90 cubic feet, that means I would need 3 and 1/3 yards of soil, or 3600 pounds! I think that would cover my entire front and back yard. LOL
I only need 1/3 of a cubic yard, about 9 cubic feet, or 360 pounds. Don't ask my how to figure this, they were talking too fast for me to write it down. :)
I am making two new beds, one on each side of my sidewalk going up to my front door. Each one is in the shape of a piece of pie. I used water hose to lay out the design, sprayed the St. Augustine with Roundup two weeks ago, and then had some guys dig out the grass and dirt for me. They dug down one foot. So, I have two pie piece shaped holes in my front yard, 45 sq. feet each, one foot deep. Does that make sense?
Yes, John, I will be buying a soil/compost mix from the City of Plano. The excavated dirt and grass was hauled off (don't know where to). It was mostly hard, clay like soil that has never been amended (my house was built 30 years ago).
Trunnels, to get the volume of your hole, you want to multiple length x width x depth. If, for example, your bed is nine feet long, ten feet wide, and 1 foot deep then 9x10x1=90. Nine cubic feet really isn't very much soil, and you'd think a yard of the stuff would go farther than it does. I built three raised beds in my yard. They are about (without remeasuring) 4x7, 5x15, and 7x50 (but the big one surrounds my pond, so it is an oval of soil, not a solid block) and I used almost six yards of soil. It was a lot of work but I had a good time and everything looks great now. I hope this helps. I'd be willing to be told I was figuring it wrong, but I really don't think that I am.
It always have to put things in 3-D (Sketch attached). If you can get the big bags of potting soil at 3 cubic feet, you'll need 30 x $8/ bag = $240. If you fill it with peatmoss (not recommended) a big bag is 3.8 cubic feet, you'll need 23 bags @ $8 = $184. A small pick-up will hold about a yard, so you'll need 3 loads or so. It will be much cheaper if you can find it in bulk. Be careful about buying by weight because it might be mostly water or sand which is very heavy. Here's a recipe for a perfect soil mix from "Square Foot Gardening" by Mel Bartholomew:
6 cu. ft. peat moss
4 cu. ft. vermiculite
3 cu. ft. sand
2/3 cu. ft wood ashes & charcoal
3 cu. ft. compost
1 coffee can full of lime
1 coffee can full of organic fertilizers.
Total volume of mixture 16 cu. ft. If you multiply the above by 6 that should be enough to fill your 90 cu. ft.
Excellent post jozeeben! That is the recipe I use too. Uncle Mel's perfect soil.
It is well worth the cost and work required to mix it. However, one is sometimes required to work with the materials at hand. I substituted the sand part with the the topsoil I allready had. The vermiculite should be a coarse grade. If Terrie's soil/compost mix is loose and friable that might work as well.