Gardeners often complain that they never have enough good soil or compost. Sometimes you need a lot more than a couple of 40-pound bags you can pick up at the garden center. Maybe the dirt in your new yard is poor or you're putting in raised beds and you need a significant amount of soil. When you need a large quantity of soil or compost, it's quicker and cheaper to buy it in bulk.
What Is Topsoil?
Topsoil usually refers to the top 2 inches of ground soil. Unfortunately, there's no standard, guideline, or law that defines the contents of bulk topsoil. When you see topsoil offered for sale, it might be rocky or full of debris, or, it might be beautiful loam. That's why it's recommended that you take a look at the soil before you purchase and have it delivered.
Where to Buy Topsoil
Ask around and get recommendations from other gardeners, professionals at garden centers, and from your local Cooperative Extension. Most avid gardeners eventually buy in bulk and they'll be the best judges. Get several opinions as a company's reputation can fluctuate.
What to Look for in Topsoil or Mulch
Even with a few great recommendations, it would still be wise to take a look at the product before purchase. Companies that specialize in providing soils will usually have several blends available, such as topsoil, lawn soil, garden soil, and compost/soil blend. Some will even allow you to create a mix, such as 40 percent compost with 60 percent topsoil. Just be sure to check if there's an additional charge for mixing.
Good topsoil and compost should have no odor other than a rich, earthy smell. It should be loose and crumbly. Even straight compost should not be coarse or chunky. Freshly made compost may still have some heat, but it shouldn't be hot.
For garden soil, a sandy loam is ideal. Look for less than 15 percent clay and at least 5 percent organic matter. It should be dark in color, crumbly, and loose feeling. There should be some moisture, but it should not form a hard ball in your hand.
Inquire about the following characteristics when purchasing topsoil in bulk:
- Soil pH: Ideally your topsoil should be somewhere between 5.5 and 7.5. You may need to test this yourself if this information is not available.
- Organic content: Find out how much compost is in the mix and what is the compost made from. Many places make theirs with yard and leaf waste, others bring in material.
- Percentage of clay, sand, and loam: You don't want an excess of clay or sand.
- Screening: Be sure the soil has been run through a screening process—you don't want a lot of rocks, litter or clumps of clay in the mix.
- 98 percent weed-free: The last thing you need is to bring in soil or compost that is going to sprout and cause you more work weeding.
It's possible to have the soil professionally tested, but it will take time and can cost anywhere from $10 to more than $100. Some companies may have a soil analysis or some form of certification available, but a good recommendation from someone you trust is your best bet.
The cost of topsoil will vary by location, quality, and quantity. There will also be a fee if you want it delivered. Creating quality topsoil requires a lot of time, labor, and expensive equipment. It's not as easy as sending your bulldozer out to scoop up soil from a vacant lot.
If you have a pickup truck, most soil companies will allow you to pull in and have the soil funneled into the bed. You will probably need to schedule a time—although smaller operations may allow you to shovel it in yourself. Without a truck, you are going to need to have the soil delivered. There's usually a fixed fee for drop off, depending on the distanced traveled.
Give some thought to where you would like the soil to be dumped when it arrives. A truck full of soil will be very heavy—driving across your lawn will certainly leave ruts. If the ground is wet, the truck's wheels may spin and even get stuck. It's usually better to find somewhere that you can lay out a large tarp, such as the side of the driveway, and have them dump the soil there. That means you'll have to shovel it into a wheelbarrow and move it load by load. The good news is once it's dumped, you can work at your own pace.
If you can't spread the pile immediately, cover it with a tarp. Rain will compact the soil or compost and make it even heavier to move. It can also make an anaerobic compost pile condition which can create a foul odor.
How Much Soil or Mulch Do You Need?
Bulk soil and mulch are sold by the cubic yard. Follow these steps to calculate how many cubic yards you'll need for different planting depths:
- Measure the square footage (length x width) of the space to be covered.
- Decide how deep you want your mulch.
- Use the chart below and select the number of inches of coverage.
- Look across to the corresponding number under "Materials Sold by Cubic Yard."
- Divide the square footage of your garden by the number from the chart.
Calculate the amount of needed soil for a 25-foot-by-20-foot garden:
- Your garden has an area of 500 square feet and you want 6 inches of mulch.
- The corresponding number on the chart for a 6 inches depth is 54.
- Divide your square footage (500) by 54.
- 500 divided by 54 equals 9.26.
You would need 9.26 cubic yards of soil or mulch to cover a 500-square-foot garden to a depth of 6 inches.
Topsoil Coverage Chart
|Coverage Depth||Sq. Ft. / Cu. Yard|