Garden Soil in Michigan: Compost-Blended Ground for Beds and Borders

By its third or fourth season a raised bed has usually sunk a couple of inches and stopped doing much. On the sandy outwash of the west side and the north, water and nutrients have simply run through it. On the heavy lake plain ground in the southeast, the opposite: what went in has slumped into something dense that roots argue with. Refilling and renewing those beds is what garden soil gets ordered for here more than any other job, and it is worth knowing what arrives before you decide how much of it you need.

Dark and crumbly, with compost you can see in it

Tip a wheelbarrow load out and the character is obvious. It is a soil blend enriched with organic compost, darker than the ground it is going onto, loose enough to run off a shovel and hold a shape in your hand without packing into a ball. You can pick out the compost fraction in it.

That composition is the whole point. The organic material holds moisture through a dry August stretch and still lets water move through during heavy rain, which is the balance a planting bed lives or dies by. It also feeds the soil organisms that turn organic matter into something roots can take up, which is why the blend keeps working after the first season rather than simply diluting. It is sold to be planted into as delivered, without mixing amendments through it first.

Where garden soil works on west-side sand and on southeastern clay

On sandy ground the problem is retention. Sand drains before a plant has finished drinking, and a vegetable bed on dune or outwash sand needs the organic fraction just to hold water long enough to matter. Build the bed up rather than digging it in: the blend does more sitting in a framed bed or a raised mound than it does scattered two inches thick over sand.

On the clay and clay loam of the southeast, around Saginaw Bay and across the Thumb, the problem is the reverse. Water stands, the soil goes airless, and roots stall. The same blend helps there too, but it needs height. A bed raised above the surrounding grade gives roots somewhere to be that is not saturated in April, which matters on ground that relies on tile and ditches to drain at all.

Both cases point at the same three jobs: filling raised beds and planters, starting or rebuilding flower and vegetable borders, and top dressing a tired bed with two or three inches to bring it back.

The pond edge, the entrance strip and under the pavers

Three jobs bring people to this page who should be somewhere else.

A pond or shoreline edge is the first. The armored part of that edge, the stone that takes wave and ice and spring runoff, is RipRap work, and soil placed into it will wash out. Where the blend does belong is the planted border set back behind the armor, above the water line, where the planting is doing the holding.

A construction entrance is the second. The stone apron itself wants coarse angular rock. When the entrance comes out and the strip is restored, the area is usually large and plain, which makes it a Top Soil job: a screened soil for lawn and seedbed work, not a compost-rich planting blend.

A paver patio base is the third and the simplest. Nothing organic goes under paving. It breaks down, it holds water, and frost lifts what water it holds. That layer is 21AA limestone compacted, with Stone Screenings screeded over it.

Bed depth for a tomato root, and the settling after the first winter

Depth is about roots rather than looks. Shallow herbs and salad will run in six to eight inches; tomatoes, peppers, beans and squash want more like ten to twelve to get away properly; a permanent border of perennials and shrubs wants deeper still, or wants the ground beneath it opened up so the roots can carry on down.

Then allow for settling. A freshly filled bed is loose, and it is going to lose height twice: once in the first few waterings, and again over its first winter as freeze and thaw work through it and the organic fraction breaks down. Fill proud of the frame rather than level with it, and expect to top up in the spring. Bed building runs from the thaw into late fall; frozen ground in a Michigan winter ends the season, and it ends it earlier in the Upper Peninsula and the northern Lower Peninsula than it does down south.

Yards and tons for a 26 foot pond-side border and a 44 foot patio bed

Hypothetical layouts, both. First the planted border set back from a pond edge, five feet deep and twenty-six feet long, filled eight inches deep.

• 5 x 26 = 130 square feet
• 8 inches is 0.667 feet, so 130 x 0.667 = 86.7 cubic feet
• 86.7 / 27 = 3.2 cubic yards

This site publishes about 2,000 lb per cubic yard for a blended garden soil, which is 1.00 ton per yard, so 3.2 cubic yards is 3.2 tons. That one-to-one conversion is a quirk of this blend being far lighter than stone; it does not hold for anything else on the site.

Now the planting beds framing a new patio, three feet deep and forty-four feet of run, filled ten inches deep.

• 3 x 44 = 132 square feet
• 10 inches is 0.833 feet, so 132 x 0.833 = 110 cubic feet
• 110 / 27 = 4.1 cubic yards, and 4.1 x 1.00 = 4.1 tons

Order a little over both figures. Everything above assumes finished, settled depth, and a loose blend does not stay at the height you tipped it. The soil calculator runs the same sum, takes circular beds as well as rectangles, accepts up to five separate areas and offers a five percent addition.

Fill dirt below it, mulch above it, top soil for the lawn

A bed built properly usually involves three products rather than one. Fill Dirt is the bulk material underneath, used to raise a low area or bring a frame up to within a foot of its finished height before the growing medium goes in; a compost blend is wasted in the bottom of a two foot planter where nothing will root. Garden soil is the root zone above that. Shredded Mulch goes on top once the planting is in, holding moisture through summer and keeping the surface from crusting.

Top soil is the fourth, and it is a different job entirely: lawns, seedbeds and general regrading rather than the root zone of a planted bed.

Pick a delivery date here once the yardage looks right, and give some thought to where a loose load can sit for a day. A pile of soil left on a lawn through a warm weekend leaves a scar; a tarp or a corner of the drive saves the grass.