Landscaping Dirt Guide: Understanding Topsoil, Fill Dirt, and Garden Soil in 2025
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Landscaping Dirt Guide: Understanding Topsoil, Fill Dirt, and Garden Soil in 2025

Complete guide to choosing the right dirt for your landscaping project. Learn the differences between topsoil, fill dirt, garden soil, and mulch—plus 2025 pricing and how much you need.

TheSiteMath Team December 1, 2025 12 min read

Walk into any landscape supply yard and you’ll see piles of material with similar names: topsoil, fill dirt, garden soil, planting mix. They all look like dirt—so what’s the difference? Choosing the wrong type can lead to poor plant growth, drainage problems, or structural failures. This guide explains exactly what each type is, when to use it, and how much it costs in 2025.

The Four Main Types of Landscaping Dirt

Let’s start with clear definitions of each material:

1. Topsoil

What it is: The uppermost 2-8 inches of natural soil, rich in organic matter, microorganisms, and nutrients.

Composition:

  • Sand, silt, and clay in varying proportions
  • 2-10% organic matter (decomposed plant material)
  • Active microbial life
  • Natural seed bank (may contain weed seeds)

Key Properties:

  • Supports plant growth
  • Good moisture retention
  • Contains nutrients
  • Dark color (from organic content)

Best Uses:

  • Establishing new lawns
  • Filling low spots in existing lawns
  • Creating garden beds
  • Grading around foundations
  • Topdressing for lawn improvement

2. Fill Dirt

What it is: Subsoil excavated from below the topsoil layer, containing little to no organic matter.

Composition:

  • Primarily clay, sand, and rock
  • Minimal organic content
  • No active microbial life
  • Compact and dense

Key Properties:

  • Highly stable (doesn’t decompose or settle)
  • Compacts well
  • Poor for plant growth
  • Doesn’t shift over time

Best Uses:

  • Filling holes and depressions
  • Building up elevation
  • Base for concrete, pavers, or driveways
  • Backfilling around foundations
  • Creating berms (when topped with topsoil)

3. Garden Soil

What it is: A manufactured blend designed specifically for planting, combining topsoil with organic amendments.

Composition:

  • Screened topsoil base
  • Compost (25-50%)
  • Peat moss or coconite
  • Sometimes added fertilizers
  • pH-adjusted for optimal plant growth

Key Properties:

  • Nutrient-rich
  • Excellent drainage
  • Lightweight and workable
  • Premium quality (and price)

Best Uses:

  • Vegetable gardens
  • Flower beds
  • Mixing with native soil
  • Container gardening (when combined with perlite)
  • Amending poor native soil

4. Mulch

What it is: Organic or inorganic material used to cover soil surface—not a planting medium.

Types:

  • Organic: Wood chips, bark, straw, leaves
  • Inorganic: Rubber, gravel, landscape fabric

Key Properties:

  • Suppresses weeds
  • Retains soil moisture
  • Regulates soil temperature
  • Decomposes and improves soil (organic types)

Best Uses:

  • Around trees and shrubs
  • Garden bed surfaces
  • Playground areas
  • Pathway cover
  • Erosion control

Comparison Chart: Quick Reference

PropertyTopsoilFill DirtGarden SoilMulch
Organic MatterMedium (2-10%)Minimal (0-2%)High (25-50%)100% (organic types)
Nutrient ContentModeratePoorHighN/A (surface use)
Plant SupportGoodPoorExcellentN/A
Structural StabilityLowHighVery LowN/A
DrainageVariablePoorGoodExcellent
CompactionModerateHighLowDoes not compact
Cost$$$$$$$$

2025 Pricing Guide

Understanding current market prices helps you budget accurately and recognize fair quotes.

Bulk Pricing (Per Cubic Yard)

MaterialPrice RangeAverageNotes
Fill Dirt$5-25$12Cheapest option; sometimes free
Unscreened Topsoil$10-20$15May contain debris
Screened Topsoil$17-30$22Sifted, uniform texture
Premium Loam$30-55$40Lab-tested, optimal blend
Garden Soil$25-50$35Pre-mixed with compost
Compost$20-45$30100% organic matter
Mulch (wood)$20-45$30Varies by wood type
Mulch (colored)$35-65$45Dyed for aesthetics

Bagged Pricing

For small projects, bagged soil from home improvement stores:

ProductBag SizePrice RangeCoverage
Topsoil40 lb (0.75 cu ft)$3-6~6 sq ft at 1” depth
Garden Soil1-2 cu ft$5-1512-24 sq ft at 1” depth
Potting Mix1-2 cu ft$8-20Container use
Mulch2 cu ft$3-88 sq ft at 3” depth

Delivery Costs

Load SizeDelivery FeeTotal with Material
1-5 cu yards$50-100$100-300
6-10 cu yards$75-150$200-500
10-15 cu yards (full load)$100-200$300-800

Money-Saving Tip: Many suppliers offer free delivery over 10 cubic yards. Order with neighbors to share a truckload.

How Much Do You Need?

Formula

Cubic Yards = (Length × Width × Depth) ÷ 27

All measurements in feet. Depth commonly expressed in inches, so convert:

  • 1” depth = 0.083 feet
  • 2” depth = 0.167 feet
  • 3” depth = 0.25 feet
  • 4” depth = 0.333 feet

Coverage Estimates

ApplicationRecommended DepthCu Yards per 1,000 sq ft
Topdressing lawn0.25-0.5”0.8-1.5
New lawn establishment2-4”6-12
Garden bed preparation4-6”12-18
Filling low spotsVariableCalculate individually
Mulch around plants2-4”6-12

Quick Coverage Table

Cubic YardsCoverage at 2”Coverage at 4”Coverage at 6”
1162 sq ft81 sq ft54 sq ft
3486 sq ft243 sq ft162 sq ft
5810 sq ft405 sq ft270 sq ft
101,620 sq ft810 sq ft540 sq ft

Choosing the Right Material for Your Project

Project: New Lawn Installation

Material Needed: Screened topsoil Depth: 4-6” over compacted subgrade Why: Grass needs nutrients and organic matter to establish roots

Alternative: If budget is tight, use 3” fill dirt as base + 3” topsoil on top

Project: Vegetable Garden

Material Needed: Garden soil or amended topsoil Depth: 6-12” for most vegetables Why: Vegetables are heavy feeders requiring nutrient-rich soil

Recipe for DIY Garden Soil:

  • 60% screened topsoil
  • 30% compost
  • 10% perlite or coarse sand

Project: Raised Garden Beds

Material Needed: Raised bed soil mix Depth: Full bed height (typically 8-12”) Why: Raised beds need excellent drainage and high fertility

Recipe for Raised Bed Mix:

  • 50% screened topsoil
  • 30% compost
  • 20% perlite or vermiculite

Project: Filling Holes/Low Spots

Material Needed: Fill dirt (for depth) + topsoil (top layer) Method: Fill within 4” of final grade with fill dirt, cap with topsoil Why: Fill dirt won’t settle; topsoil supports grass regrowth

Project: Driveway or Patio Base

Material Needed: Clean fill dirt or crushed stone Depth: 4-8” compacted base Why: Stable base prevents settling; organic matter would decompose

Project: Foundation Backfill

Material Needed: Clean fill dirt Depth: As needed to meet grade Why: Prevents settlement against foundation; won’t retain moisture

Critical: Never use topsoil or garden soil against foundations—organic matter retains water and attracts pests.

Understanding Soil Quality

What Makes “Good” Topsoil?

Quality topsoil should have:

  1. Proper Texture – Crumbly, not sticky or dustite
  2. Dark Color – Indicates organic content
  3. Earthy Smell – Should smell like forest floor, not sour or chemical
  4. No Debris – Free of large rocks, roots, trash
  5. Appropriate pH – 6.0-7.0 for most plants

Red Flags When Buying Soil

Watch out for:

  • Very cheap topsoil – Often just screened fill dirt
  • Strong odor – May indicate contamination
  • Clumpy texture – High clay content
  • Visible debris – Poorly screened
  • Unknown origin – May contain herbicides or contaminants

Testing Your Soil

For important projects, get soil tested:

  • DIY Test Kits: $15-30, tests pH and basic nutrients
  • Extension Service: $15-50, comprehensive analysis
  • Private Lab: $50-150, detailed professional report

Layering Strategy: Best of All Worlds

For optimal results, many projects benefit from layered approaches:

Example: New Planting Bed

Layer 3 (Top): 2-3" mulch (moisture retention, weed suppression)
Layer 2 (Middle): 4-6" garden soil (nutrients, drainage)
Layer 1 (Base): 2-4" fill dirt if needed for elevation
Native Soil: Loosened 4-6" deep (integration layer)

Example: Lawn Renovation

Layer 2 (Top): 2-4" screened topsoil (seed bed)
Layer 1 (Base): Fill dirt as needed for grade corrections
Native Soil: Existing lawn or compacted subgrade

Common Mistakes to Avoid

Mistake 1: Using Fill Dirt for Planting

Problem: Plants can’t establish in nutrient-poor subsoil Solution: Always top fill dirt with 4-6” of topsoil for planting

Mistake 2: Using Garden Soil for Filling

Problem: Rich soil settles as organic matter decomposes, creating sinkholes Solution: Use fill dirt for volume, topsoil only for top layer

Mistake 3: Not Accounting for Settlement

Problem: Fresh soil compacts 10-20% over time Solution: Over-fill slightly and water deeply to encourage settling before planting

Mistake 4: Ignoring Drainage

Problem: Heavy clay soil or poor grading causes waterlogging Solution: Amend soil with sand/perlite; ensure positive drainage away from structures

Mistake 5: Buying Without Inspection

Problem: “Topsoil” may be mislabeled fill dirt Solution: Visit the supplier, inspect the pile, and ask about source

Seasonal Considerations

Best Time to Buy

  • Spring: Highest demand, highest prices
  • Summer: Good availability, moderate prices
  • Fall: Best prices, excellent for soil preparation
  • Winter: Limited availability in cold climates, best deals where available

Seasonal Projects

SeasonBest Project
Early SpringLawn renovation, bed prep
Late SpringNew plantings with fresh soil
SummerMulching to retain moisture
FallSoil amendment, lawn overseeding
WinterPlanning and bulk purchasing

Calculate Your Needs

Don’t guess on quantities—use our Dirt Calculator to determine exactly how much material you need. It handles:

  • Multiple area shapes
  • Various depth requirements
  • Conversion between cubic yards and bags
  • Cost estimates based on material type

For projects involving concrete or masonry, check our Concrete Calculator.


Bottom Line: The right dirt makes all the difference in landscaping success. Use fill dirt for structural needs, topsoil for planting areas, garden soil for high-demand plants, and mulch to protect and beautify. Match the material to the job, and your landscape will thrive for years to come.

Technical References: Soil composition guidelines from USDA Natural Resources Conservation Service. Pricing reflects 2025 US national averages from landscape supply industry data.

Topics covered:

topsoil fill dirt garden soil landscaping materials soil types mulch