Topsoil Amendments Calculator

Calculating Topsoil Amendment Needs for Gardens

In addition to buying the right quantity of topsoil, it’s important to amend it properly to enrich nutrients and texture for optimal plant growth. Here are some tips:

Test Soil Composition

Send a garden soil sample to a lab to analyze pH levels and nutrient content. This helps identify deficiencies.

Choose Suitable Amendments

Compost, manure, peat moss, and leaf mold work well to balance and enrich soil for planting.

Determine Amendment Ratio

A typical mix is 20-30% amendments to 70-80% existing or new topsoil. More amendments are needed for poor native soil.
Here are some examples of typical amendment rates:

- Compost: 1-3 inches applied to the soil surface and incorporated into the top 6-8 inches of soil.
- Manure: 1-2 inches applied to the soil surface and incorporated.
- Peat moss: 1-2 cubic feet per 100 square feet of soil surface area.
- Lime: Application rates vary depending on soil pH and soil type. A soil test is recommended to determine the appropriate rate.

Remember, these are just general guidelines. It's always best to tailor the amendment rate to your specific soil and gardening needs.

Use a Garden Soil Amendments Calculator

Simply input the garden Area(sq ft) size, Depth(in) and Amendment Rate(lbs per sq ft) and you will get the Total Ammendments Needed in lbs.

Order Amendments in Advance

Procure compost, manure or other amendments ahead of the topsoil delivery to allow time for mixing.

Thoroughly Incorporate Amendments

Use a rototiller or spade to mix amendments 6-12 inches deep into the garden's topsoil before planting.