How much soil for a 4x8 raised bed?

A 4×8 foot raised bed filled to 12 inches deep needs approximately 32 cubic feet (about 900 litres) of soil mix. Most gardeners use 60% topsoil, 30% compost, and 10% drainage material like cocopeat or perlite.

What is the best soil mix ratio for vegetables?

For vegetable gardens, use approximately 50% potting soil, 40% compost, and 10% drainage material. Vegetables need more nutrients than ornamentals, so compost is increased compared to a standard mix.

Soil Amendment Calculator

Q: What should I add to potting soil to keep plants healthy?

Once your pots are filled with a good mix, add a slow-release fertilizer like Nutripot Soil Tab at planting and re-feed every 4–6 weeks. For flowering plants, switch to Nutripot Floret Tab before bloom season for better flowering.

Soil & Amendment Calculator

Find out exactly how much soil, compost, and mulch you need

Pot Diameter (top)

Pot Depth

Number of Pots

Plant Type

Length

Width

Soil Depth (fill height)

Plant Type

Length

Width

Amendment Depth (how deep to mix in)

Plant Type

Estimates are based on standard horticultural ratios. Actual amounts may vary slightly with soil compaction and ingredient density. Always buy 5–10% extra to account for settling.

How to Use the Soil Calculator

Choose your container type — round pot, raised bed, or ground bed — enter the dimensions, pick your plant type, and we’ll calculate exactly how much potting soil, compost, mulch, and starter fertilizer you need. The calculator works in both metric (cm, metres) and imperial (inches, feet) units.

Recommended Soil Mix Ratios

For most home gardens, a 60% potting soil + 30% compost + 10% drainage material (cocopeat or perlite) mix works well. Vegetable gardens benefit from extra compost (40%) for nutrients, while cacti and succulents need more drainage — about 50% sand or perlite. The calculator automatically adjusts the mix based on the plant type you select.

Frequently Asked Questions

How much soil do I need for a 12-inch pot?

A standard 12-inch round pot with 10 inches of depth needs roughly 11–12 litres of potting mix. Use the calculator above for exact amounts based on your specific pot size.

How much soil for a 4×8 raised bed?

A 4×8 foot raised bed filled to 12 inches deep needs approximately 32 cubic feet (or about 900 litres) of soil mix. Most gardeners go with 60% topsoil, 30% compost, and 10% drainage material.

Once I fill my pots, what should I add to keep plants healthy?

A good potting mix gets you started, but plants deplete soil nutrients within a few weeks. Add a slow-release fertilizer like Nutripot Soil Tab at planting and re-feed every 4–6 weeks. For flowering plants, switch to Nutripot Floret Tab before bloom season.

Need product recommendations for your specific plant problem? Browse our full Nutripot catalog.