Garden & Outdoor
Potting Soil Mix Calculator
Calculate the right amounts for your soil-compost-sand mix – tailored to beds, raised beds or planters.
Enter the total volume you need and the mix ratio of compost, garden soil and sand. The calculator automatically splits the total into the right proportions.
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Compost / soil / sand
Pro tips
- Sand improves drainage – important for plants sensitive to waterlogging.
- Compost provides nutrients but should not exceed half of the total mix.
All calculations are non-binding estimates provided without guarantee. For safety-relevant decisions (e.g. pool chemistry), please consult a professional.
Frequently Asked Questions
What mix ratio is typical for soil-compost-sand blends?
For most beds, a ratio of roughly 60% garden soil, 30% compost and 10% sand works well, depending on plant needs and soil condition.
Why add sand to a soil mix?
Sand improves drainage and loosens heavy, clay-rich soil so water can drain better and waterlogging is avoided.
How much compost should go into the mix?
A 20-30% compost share is usually enough to add nutrients without over-fertilizing the mix.
Can I use the same mix for raised beds and planters?
Generally yes, but for planters a slightly higher sand or drainage share is often worthwhile, since excess water drains away less easily there.