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Hügelkultur Calculator — Logs, Compost & Soil by Mound Size

Calculate materials for your hügelkultur mound bed

Total Volume

72 ft³

Logs

36 ft³

Compost

18 ft³

Topsoil

18 ft³

Typical h\u00FCgelkultur beds are 3–6 ft tall, 4–6 ft wide, and 6–20 ft long.

Total Mound Volume

72 ft³

12 × 4 × 3 ft mound

Logs

36

ft³

Compost

18

ft³

Topsoil

18

ft³

Weight Estimates

Logs (dry)900 lbs
Compost720 lbs
Topsoil1,350 lbs

Layer Ratios

Logs (bottom)50%
Compost (middle)25%
Topsoil (top)25%

What You'll Need

GARDEN STAR 5 Cu Ft Poly Tray Wheelbarrow

GARDEN STAR 5 Cu Ft Poly Tray Wheelbarrow

$65-$904.4
View on Amazon
VIVOSUN 3-in-1 Soil pH/Moisture/Light Tester

VIVOSUN 3-in-1 Soil pH/Moisture/Light Tester

$10-$154.3
View on Amazon
Best Choice Cedar Raised Garden Bed 4x2ft

Best Choice Cedar Raised Garden Bed 4x2ft

$40-$554.5
View on Amazon
Espoma Organic Raised Bed Mix 1.5 Cu Ft

Espoma Organic Raised Bed Mix 1.5 Cu Ft

$15-$204.5
View on Amazon

2-in-1 Garden Kneeler and Seat Foldable 400lb

$42-$484.8
View on Amazon

FCMP Outdoor HOTFROG Roto Tumbling Composter

$148-$1604.6
View on Amazon
GARDEN STAR 5 Cu Ft Poly Tray Wheelbarrow

GARDEN STAR 5 Cu Ft Poly Tray Wheelbarrow

$65-$904.4
View on Amazon
VIVOSUN 3-in-1 Soil pH/Moisture/Light Tester

VIVOSUN 3-in-1 Soil pH/Moisture/Light Tester

$10-$154.3
View on Amazon
Best Choice Cedar Raised Garden Bed 4x2ft

Best Choice Cedar Raised Garden Bed 4x2ft

$40-$554.5
View on Amazon
Espoma Organic Raised Bed Mix 1.5 Cu Ft

Espoma Organic Raised Bed Mix 1.5 Cu Ft

$15-$204.5
View on Amazon

2-in-1 Garden Kneeler and Seat Foldable 400lb

$42-$484.8
View on Amazon

FCMP Outdoor HOTFROG Roto Tumbling Composter

$148-$1604.6
View on Amazon

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Example Calculations

1Standard 12×4×3 ft Mound

Inputs

Length12 ft
Width4 ft
Height3 ft

Result

Total Volume72 ft³
Logs36 ft³
Compost18 ft³
Topsoil18 ft³

Volume = 0.5 × 12 × 4 × 3 = 72 ft³. Logs = 72 × 0.50 = 36. Compost = 72 × 0.25 = 18. Topsoil = 72 × 0.25 = 18.

2Large 20×6×4 ft Mound

Inputs

Length20 ft
Width6 ft
Height4 ft

Result

Total Volume240 ft³
Logs120 ft³
Compost60 ft³
Topsoil60 ft³

Volume = 0.5 × 20 × 6 × 4 = 240 ft³. Logs = 120, Compost = 60, Topsoil = 60.

Frequently Asked Questions

Q

How much wood do I need for a hügelkultur bed?

Wood logs should fill about 50% of the mound volume. For a standard 12 ft × 4 ft × 3 ft hügelkultur bed (36 cu ft total), you need about 18 cu ft of logs, weighing roughly 450 lbs of dry hardwood. Use branches, logs, and stumps 2–12 inches in diameter.

  • Standard 12×4×3 ft mound = 36 cu ft total, 18 cu ft logs (~450 lbs dry)
  • Hardwood (oak, maple) is best — decomposes slowly over 5–10 years
  • Avoid black walnut (toxic juglone), cedar (too acidic), pressure-treated wood
  • Mix log sizes: large logs at bottom, branches and sticks on top
  • Green wood works fine — it absorbs water and decomposes slowly
Q

How tall should a hügelkultur bed be?

Hügelkultur beds are typically 3–6 feet tall. Taller beds (5–6 ft) retain more moisture and produce warmer soil but settle 30–40% in the first year. A 3 ft bed is ideal for most home gardens and settles to about 2 ft.

  • 3 ft: beginner-friendly, settles to ~2 ft, easy to plant and access
  • 4 ft: good balance of moisture retention and accessibility
  • 5–6 ft: maximum water retention, creates microclimates, hard to reach top
  • Beds settle 30–40% in year one as wood begins decomposing
  • Build 50% taller than your target final height to account for settling
Q

How long does a hügelkultur bed last?

A hügelkultur bed with hardwood logs produces for 10–20 years before the wood fully decomposes. Softwood beds last 5–8 years. The bed improves each year as decomposing wood releases nutrients and acts as a sponge, holding water through dry periods.

  • Hardwood (oak, maple): 10–20 year lifespan, slow nutrient release
  • Softwood (pine, spruce): 5–8 years, faster decomposition
  • Year 1: nitrogen tie-up may occur — add extra compost or nitrogen
  • Years 2–5: peak performance, wood sponge effect reduces watering by 50%
  • Years 5–10+: rich humus forms, virtually no watering needed in most climates
Q

What are the layers of a hügelkultur bed?

Bottom to top: logs and branches (50% of volume), then compost or manure (25%), then topsoil (25%). Some builders add a cardboard base layer and nitrogen source (blood meal) between the logs and compost to speed initial decomposition.

  • Layer 1 (base): large logs and stumps — forms the core moisture sponge
  • Layer 2: smaller branches and wood chips — fills gaps between logs
  • Layer 3: compost, manure, or leaf mold (25%) — provides nitrogen
  • Layer 4: topsoil or garden soil (25%) — planting medium on top
  • Optional: cardboard under logs to suppress grass, blood meal for nitrogen boost

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Last Updated: Mar 19, 2026

This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.

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