Garden Soil Calculator
— How Much Do You Need?

Garden soil is a blended growing medium specifically formulated to support healthy plant growth. It typically contains a mix of natural soil, compost, and organic matter that gives your plants the nutrients, loose structure, and drainage they need to thrive. Topsoil is different. It is the natural upper layer of earth and contains far fewer amendments than garden soil. Topsoil works well for grading your lawn, leveling your yard, or topping off low spots, but it is not enriched the same way garden soil is. Fill dirt is something else entirely. It is a subsoil material with little to no organic content, used to fill voids, build up grade, or create a structural base beneath other materials. Fill dirt will not support meaningful plant growth, and it is not what you want going into your garden beds. If your goal is to grow vegetables, flowers, or herbs, garden soil is the right call. If you are working on lawn grading or leveling your property, topsoil is likely the better fit. Not sure which material makes more sense for your project? The Hello Gravel team is happy to help you figure it out before you place your order.

Bulk garden soil is the right material whenever you need a nutrient-rich growing medium in large quantities. It is most commonly used to fill raised garden beds from scratch, create new in-ground vegetable or flower gardens, refresh and rebuild depleted planting areas, and establish landscaping borders or mixed planting zones. If you are starting a large vegetable garden for the first time, putting in several raised beds at once, or expanding your growing space significantly, ordering garden soil by the truckload gives you everything you need in a single delivery. It is also a smart choice when you are rehabilitating an area with poor, compacted, or heavily clay-based soil and need a fresh growing layer to work with. Keep in mind that garden soil is designed specifically for planting. It is not the right material for filling large structural voids, grading your property, or creating a base beneath hardscaping. For those needs, fill dirt or topsoil is the more appropriate choice.

The amount of garden soil you need depends on two things: the total square footage of your planting area and how deep you plan to fill it. As a general reference point, one cubic yard of material covers approximately 324 square feet at one inch deep, 162 square feet at two inches deep, or 108 square feet at three inches deep. For most garden installations, you are working with much greater depths than that, so the volume adds up quickly. For example, filling a 10-by-20-foot raised bed to a depth of 12 inches requires roughly 7.4 cubic yards of material. If you have multiple beds or a large in-ground garden at deeper depths, your total will climb fast. The most accurate way to get your number right is to use the Hello Gravel online calculator. Enter your dimensions and your target depth, and it will give you a reliable estimate tailored to your specific project so you can order with confidence rather than guessing.

Depth matters more than most people realize, and getting it right up front saves a lot of frustration later. For raised garden beds, most experienced gardeners recommend a minimum of 8 to 12 inches of garden soil. Root vegetables like carrots, beets, and parsnips perform best with at least 12 inches of depth to grow into. Shallow-rooted crops like lettuce, herbs, and most annual flowers can do well in 6 to 8 inches. For in-ground gardens, you have two main approaches depending on what you are starting with. If your existing soil is reasonably healthy but compacted or worn down, tilling in 4 to 6 inches of fresh garden soil as an amendment often gives you a significant improvement in plant performance. If your native soil is poor, heavily clay-based, or very sandy, bringing in 6 to 12 inches of garden soil as a dedicated growing layer gives your plants a much better environment from the start. Whichever approach fits your situation, the Hello Gravel calculator makes it straightforward to translate your chosen depth and area into a precise quantity so you know exactly how much to order.

Both approaches work, and the right choice depends on what you are starting with. If your existing beds have become compacted or nutritionally depleted over several growing seasons, tilling fresh garden soil into the existing material is a practical and effective strategy. You loosen the existing soil to a depth of 6 to 8 inches, then incorporate your new garden soil into that loosened layer. This blending method works especially well when your native soil has decent drainage but needs a structural and organic boost to perform well again. If your native soil is heavily clay-based, very sandy, or just plain poor, you will get better results by bringing in a thicker layer of fresh garden soil and minimizing how much you blend with the native material beneath it. For raised beds, the approach is typically simpler: fill the beds entirely with garden soil since the frame already isolates the growing medium from the ground below. Either way, ordering in bulk means you will have plenty of material to work with and will not find yourself running short halfway through the project.