What "black dirt" actually means around here
Central Illinois sits on some of the deepest prairie soil in the country. Generations of grass grew and died and rotted in place here, which is why dark, organic rich dirt is ordinary rather than precious in the Bloomington and Normal area. Every supply yard has a pile of it, and it is cheap by the yard compared to almost anything you can carry out of a garden center.
That said, "black dirt" is not a defined product term. It describes a color. Color usually does mean organic matter, since decomposed plant material darkens soil, but high iron or magnesium content can darken soil too, and so can clay heavy subsoil scraped off a construction site. A pile can be nearly black and still be lousy for a vegetable bed. Of the two terms buyers hear most, topsoil is the one with an actual definition behind it. It refers to the upper layer of soil where roots and biology live. Black dirt refers to how the pile looks.
So the practical takeaway is simple. Quality depends on the supplier and on whether the material has been screened, not on the word painted on the sign. When you call a yard, ask two questions. Is it screened, and what was it screened to. A supplier who knows the answer is a supplier worth buying from. A supplier who says "it is just black dirt" is telling you something too.
Our garden soil is a step past raw black dirt. It is screened topsoil blended with finished compost, roughly 70/30. That ratio matters because it means the material arrives ready to plant into rather than as a base you still have to fix. You are not buying dirt and then buying amendments. You are buying the finished mix.
Which sets up the real comparison. Raw black dirt, blended garden soil by the yard, and a pallet of bagged garden blend are three different purchases with three different price points and three different amounts of work attached. They get treated as one decision, and that is where people go wrong.
What is actually inside a bag of garden blend
Pick up a bag of garden soil or raised bed mix and turn it around. The ingredient panel usually lists some combination of bark fines, peat moss, composted forest products, and coconut coir. What you generally will not find listed is mineral soil. Product teardowns that go shelf by shelf through a garden center keep landing on the same finding, which is that bagged soil is mostly organic matter and may contain no actual soil at all.
That is not automatically a problem. Light organic mixes are pleasant to work with. They are fluffy, they drain fast, they are easy to plant into, and a first season bed filled with them often looks great. Seedlings go in without a fight and roots move through the material freely.
The trouble shows up in year two and three. A bed filled only with light organic material settles. It dries out fast between waterings because there is nothing in it that holds water tightly. When peat and bark fines dry hard they can turn water repellent, so the surface crusts and irrigation sheets off the top instead of soaking down into the root zone. And organic matter is, by definition, breaking down. That is what it does. So the bed loses volume every single year, and by the third spring you are hauling in more bags to bring it back up to the top rail.
Mineral soil is the part that fixes all of this. The sand, silt, and clay fraction holds moisture and holds nutrients, and it does not disappear, so the bed stops shrinking. Black dirt brings that mineral fraction. Most bags do not.
The target you are actually aiming for is loam. Dark, crumbly, smells earthy when you turn it, holds its shape when you squeeze a handful but breaks apart easily when you poke it. That texture is the whole goal. Neither pure black dirt nor pure bagged mix gets there on its own, which is worth keeping in mind before we get to the price comparison, because the cheapest option is not automatically the right one and the most expensive one is definitely not.
The cost math, per cubic foot and per bed
Bags per cubic yard
One cubic yard is 27 cubic feet. That is three feet by three feet by three feet. The most common bag size at a garden center is 1.5 cubic feet, so 27 divided by 1.5 is 18 bags to equal one cubic yard. At 2 cubic feet per bag, 27 divided by 2 is 13.5, so call it 14 bags.
Eighteen bags is a full cart, or more realistically two carts, and it is a yard of soil that would fill about a third of a small pickup bed if it were loose. A pallet of bags looks like a mountain. It is not as much volume as it looks.
Where the break-even lands
To compare honestly, put both products on the same unit. Take the bag price, divide by the cubic feet in the bag, then multiply by 27. That gives you the cost of a cubic yard of that bagged product. Now set it next to a delivered price per yard of bulk soil.
The gap is not marginal. Published figures put a cubic yard's worth of premium bagged raised bed soil around 180 dollars, while a cubic yard from a bulk supplier commonly runs in the 30 to 50 dollar range. Even after delivery, that is not a close contest once you need any real volume.
Break-even generally arrives somewhere around one and a half to two cubic yards. Below that, bags can genuinely make sense, because with a small order there is no volume to spread a delivery fee across. Above that line, bulk pulls ahead fast and keeps pulling, because delivery is mostly a fixed cost while bags charge you the same premium on every single one.
Also count the costs that never make it onto the price tag. Somebody loads those bags into a cart, out of the cart into a vehicle, out of the vehicle at home, and then drags each one to the bed. If your car only holds ten bags at a time, a two yard project is four trips. And at the end you have a heap of empty plastic bags to deal with.
Bags still win in specific situations, and it is worth naming them. One container or a few pots. A small patio bed. A property with no reasonable place to put a pile. A driveway too tight or too soft for a dump truck to back down. If any of those describe you, buy the bags without guilt.
How much soil you actually need
Here are our working numbers. Garden soil runs about 1 ton per cubic yard. One cubic yard covers about 54 square feet at 6 inches deep. Typical install depth for planting beds is 6 to 12 inches, deeper if you are growing root crops or filling a tall raised bed frame.
Work an example. A standard 4 by 8 foot raised bed is 32 square feet. Fill it 12 inches deep and that is 32 square feet times 1 foot of depth, which is 32 cubic feet. Divide 32 by 27 cubic feet per yard and you get about 1.2 cubic yards. In bags at 1.5 cubic feet each, 32 divided by 1.5 is roughly 21 bags for that one bed.
Now build two of those beds. Two times 1.2 is about 2.4 cubic yards, or somewhere around 43 bags. That is comfortably past the break-even point, so it is a bulk order and it is not a close call. If you are working out your own number, our bulk garden soil delivered by the yard page has the coverage figures in one place.
Order a little extra. Fresh soil settles noticeably after the first few waterings, and beds always swallow more than the tape measure suggests, especially if the ground under them is uneven. Rounding 1.2 yards up to 1.5 costs very little. Making a second trip costs an afternoon.
One more thing about weight. At about 1 ton per cubic yard, a full yard of garden soil is around 2,000 pounds. Most half ton pickups have no business carrying that in a single load, and a wet yard is heavier still. If you are hauling it yourself, plan on half yard loads. This is the quiet reason delivery is worth paying for on anything past a yard or so.
The actual winner, bulk black dirt cut with compost
For anything larger than a container or two, the answer is bulk soil with compost in it. That combination gives you mineral soil to hold water and nutrients, plus organic matter for structure, drainage, and fertility. Bags give you the second half and skip the first. Raw black dirt gives you the first half and skips the second.
Our garden soil arrives already blended, screened topsoil with finished compost at roughly 70/30. There is nothing to mix in the driveway. You fill the bed and plant.
If you are starting from plain screened black dirt instead, mix the compost into it before it goes in the bed. Do not fill the bed with dirt and then spread compost on top and call it done. A distinct layer of one material sitting on another creates a seam, and roots and water both stall at seams. Turn the two together on a tarp or in the wheelbarrow and put the finished mix in.
The same logic applies at the bottom of the bed. Work the top few inches of your new soil into the existing soil underneath it so roots cross the boundary instead of hitting an abrupt texture change and circling in the new material. Five minutes with a garden fork before you fill is enough. It is the single install step people skip most, and it is the reason some beds root deep and others stay shallow.
Then plan on a refresh. Top the bed with an inch or two of compost each spring. Organic matter burns off over the season, and that annual layer is what keeps a bed producing for years without a teardown and rebuild.
Last warning on this. If you are building a raised bed on native ground, do not use fill dirt as the growing layer. Fill dirt is subsoil sold for bringing up grade and backfilling low spots. It is fine for that and it is bad for roots. Use it under a patio, not under tomatoes.
Weed seeds, clods, and the honest downsides of bulk
Bulk soil is real soil, and real soil carries weed seed. Bagged mixes tend to start cleaner because the composting process they go through generates enough heat to kill most of what is in there. This is the legitimate argument for bags, and it is worth being straight about.
It is also manageable. Most of what sprouts in a new bed is annual weeds, and annual weeds die when you cut them off at the soil line. A pass with a hoe every week or two for the first month handles it. Better still, put mulch down on the bare soil between plants. Blocking light dramatically reduces how many seeds germinate in the first place, and you were probably mulching anyway.
Ask the supplier whether the material is screened. Screened soil has been run through a mesh to pull out rocks, root chunks, and clods. Unscreened soil is genuinely unpleasant to plant into and you will feel it on every trowel stroke.
Moisture is the other real downside. A pile dumped the day after a heavy rain is sticky and enormously heavy, and if you shovel and work clay heavy soil while it is wet you compact it and lose the crumbly structure you paid for. Wait a day or two of decent weather. It handles like soil again once it dries down.
Finally, be honest with yourself about labor and space. You need somewhere for the pile to sit, ideally on the driveway where you can shovel off pavement, and you need a wheelbarrow. Moving two or three yards from the driveway to the backyard is a real afternoon of work. It is still cheaper and better soil than the bagged alternative, but nobody should be surprised by it at four in the afternoon.
How We Started
We started Mulch Mound because we got tired of the hassle that came with buying landscaping materials. The options were either loading bags into your car at a garden center or calling around to local suppliers, trying to figure out pricing, minimums, and delivery schedules. Neither option felt convenient or transparent.
Three of us – Alec, Mo, and Tyler – decided there had to be a better way. Alec and Tyler got their start back in 2013 running a landscaping business during college, moving mulch and mowing lawns to pay tuition. That experience taught them how frustrating it was to source materials, and years later, that frustration turned into Mulch Mound.
We focus on making it simple to get mulch, stone, and soil delivered directly to your home. Order online, pick your delivery date, and we handle the rest. No loading bags. No calling multiple suppliers. No wondering if you bought enough or paid a fair price.
We work with quality local suppliers in the areas we serve and aim to be straightforward about what we offer and what it costs. Landscaping is hard work. Buying the materials for it shouldn't be.
Frequently asked questions
Is black dirt the same thing as topsoil?
Not necessarily. Topsoil has a defined meaning, the upper layer of soil where organic matter and biology are concentrated. Black dirt just describes color, and in some parts of the country it means something specific and different. In parts of New York and Florida the term refers to material dug from drained swampland, which is a peat heavy soil that behaves nothing like Illinois prairie topsoil. Ask a supplier what the material is and where it came from rather than what it is called.
Why does bagged garden soil crust over in a raised bed?
Mixes built mostly on peat and bark fines can become water repellent once they dry out hard. The surface tightens into a crust and water runs across it rather than soaking in, which fools people into thinking the bed is watered when the root zone is still dry. Scratching the top inch with a hand cultivator breaks the crust, and keeping a mulch layer on top stops it from forming. The permanent fix is mineral soil in the mix, which is exactly what bagged products leave out.
Can I plant into black dirt straight, with no compost?
You can and things will grow. But heavy prairie dirt on its own tends to pack down in a confined space like a raised bed, especially once you have watered it a few dozen times and walked around it. Packed soil means poor drainage and roots that struggle. Compost is what keeps the mix crumbly and open. If you have already filled a bed with straight black dirt, you are not stuck. Fork a few inches of compost into the top eight inches and you will feel the difference within a season.
Should I fill the bottom of a deep raised bed with something cheaper?
For beds deeper than about a foot, yes, you can bulk out the bottom with coarse organic material like small branches, leaves, or rough wood chips. Just keep the top 8 to 12 inches as real growing soil, because that is where most vegetable roots actually live. Expect that bottom layer to break down and the bed to drop over the first couple of years, so plan on topping it up.
How many bags of garden soil equal a cubic yard?
Eighteen bags at 1.5 cubic feet, or about 14 bags at 2 cubic feet, since a cubic yard is 27 cubic feet. Run that count before you start loading a cart at the garden center. A stacked pallet reads as a huge quantity and often works out to a yard or less, which is the moment most people realize the bulk pile was the better buy.