Mount Depth Fit Calculator

Plant preset

Presets set reasonable cover and settlement values.

Units

Values are converted safely for accuracy.

Container/bed depth *

Enter a valid depth.

Root ball height *

Enter a valid root ball height.

Drainage layer thickness

Use 0 for no drainage layer.

Mulch thickness

Mulch reduces usable soil depth at the top.

Soil cover above root ball

Small plants: 2–3. Shrubs: 5+. Trees: 6+.

Settlement factor (%)

Accounts for settling after watering and rain.

Safety clearance

Extra clearance for compaction and uneven surfaces.

New Calculation

Tip: For a mound, enter mound height above ground as depth.

Example data

Scenario	Depth	Drainage	Mulch	Root ball	Cover	Settle	Clear	Outcome
Vegetable bed	30 cm	0 cm	3 cm	18 cm	3 cm	7%	1 cm	Fits, small margin
Shrub planter	40 cm	5 cm	4 cm	28 cm	5 cm	8%	2 cm	May not fit
Herb mound	20 cm	0 cm	2 cm	10 cm	2 cm	6%	1 cm	Fits comfortably

These examples illustrate typical layer tradeoffs.

Formula used

Available Soil Depth = Depth − Drainage Layer − Mulch − Safety Clearance
Required Depth = (Root Ball Height + Soil Cover) × (1 + Settlement% ÷ 100)
Fit Margin = Available Soil Depth − Required Depth
Max Root Ball = (Available ÷ (1 + Settlement%)) − Soil Cover

Settlement increases required depth to keep plants covered.

How to use this calculator

Measure total depth of the mount, bed, or container.
Enter drainage and mulch if you use them.
Measure root ball height from base to top.
Choose a preset, then adjust cover or settlement.
Calculate and use margin to fine-tune depth.

If you get “No fit,” increase depth or reduce layers.

Depth planning improves root performance

Mount depth determines how much stable soil surrounds the root ball after watering and weather. Shallow mounts dry quickly, expose roots, and reduce anchoring. Deeper mounts buffer temperature swings and hold moisture longer, supporting uniform feeder-root growth. This calculator translates your measured mount depth into usable soil depth by removing mulch, drainage layers, and a small safety clearance.

Why settlement must be included

Fresh mixes often settle 5–12% after the first heavy irrigation, rain events, or light compaction. A settlement factor prevents underestimating required depth. The required depth is calculated from root ball height plus soil cover, then expanded by the settlement percentage. This produces a practical target that keeps crowns covered and reduces rework.

Interpreting the fit margin

Fit margin equals available soil depth minus required depth. A positive margin indicates extra space for topdressing, seasonal mulch refresh, or minor grade changes. A negative margin indicates a shortfall. Use the recommended depth output to size an amended bed, build a taller mound, or reduce non-soil layers where appropriate.

The “max root ball” value is a fast sizing check when shopping plants. If your preferred plant exceeds the maximum, either raise the mount, choose a smaller container size, or plan to remove some mulch thickness after establishment.

Using presets for common crops

Presets provide starting values for soil cover, settlement, and clearance. Herbs and seedlings typically need smaller cover values, while shrubs and small trees benefit from deeper cover and a slightly higher clearance. Always adjust presets for local conditions: windy sites may need more cover, and very coarse mixes may settle less than fine blends.

Exporting results for planning and purchasing

Exported CSV files help compare multiple mount designs in a spreadsheet, while the PDF report is useful for sharing with clients or crews. Record the scenario, depth, and margin, then standardize your preferred cover and settlement settings. Consistent inputs make future projects faster, and reduce guesswork during planting days across multiple garden projects.

FAQs

1) What does “available soil depth” represent?

It is the usable soil space after subtracting drainage, mulch, and clearance from total mount depth. It reflects the depth that can actually surround the root ball.

2) How do I choose a settlement factor?

Use 5–12% for most fresh mixes. Choose higher values for fluffy blends or newly filled beds, and lower values for aged, lightly compacted soil that has already stabilized.

3) Why include safety clearance?

Clearance accounts for uneven grade, minor compaction, and measurement error. It helps prevent borderline “fits” that become exposed after watering, rainfall, or foot traffic.

4) What should I do if the result shows “No fit”?

Increase mount depth, reduce mulch or drainage thickness, or select a smaller root ball height. The recommended depth value shows a practical new target.

5) Can I use inches instead of centimeters?

Yes. Select inches in the Units field, enter measurements in inches, and the calculator handles conversions internally for consistent results and clean CSV/PDF exports.

6) How accurate are the exports?

Exports reflect the last successful calculation stored in your session. Recalculate after changing inputs, then download CSV or PDF to ensure the saved report matches your latest design.