Horticultural Grade Pumice – 3/8" to 1/16"

Improve the structure of your specialty growing mixes with natural Oregon volcanic pumice. This horticultural-grade pumice contains a blend of particle sizes from approximately 3/8" to 1/16", along with some fines.

Mined in the Southern Cascade Mountains of Oregon, our pumice is a natural volcanic material known as the "rock that floats." Its many tiny air pockets make it a useful ingredient in a variety of soil mixes for containers, bonsai, cactus, succulents, and specialty nursery plants.

Product Features

• Natural volcanic pumice mined in Oregon's Southern Cascade Mountains

• Approximate particle size: 3/8" to 1/16"

• Blend of particle sizes with some fines

• Clean pumice with no rocks, roots, or other debris

• Natural porous structure with tiny air pockets

• Suitable for horticultural soil mixes, bonsai, cactus, succulents, and containers

• Hand-packed in a bag with a reusable tie for convenient storage

Recommended Soil Mix Ratios

Use these seller-recommended proportions as starting points for your growing mixes:

General horticultural use – 15% pumice

Mix 15% pumice into soil for general horticultural applications, including:

• Japanese maples

• Raised beds

• Container plants

Water-sensitive plants – 30% pumice

Use approximately 30% pumice in mixes for:

• Gunnera

• Giant sequoia

• Sophora

• Daphne

• Monkey puzzle trees

• Franklin trees

• Other water-sensitive plants

Cactus and succulents – 60–80% pumice

Combine 60–80% pumice with 20–40% organic matter.

Bonsai soil mix

For a bonsai mix, combine equal parts:

• Pumice

• Coarse compost

• Bark

• Black lava or coarse sand

These are suggested starting ratios. Adjust your mix to suit the plant species, growing conditions, and watering practices.

Available Package Sizes and Fill Conversions

• 15 ounces

• 10 cups – fills approximately 1.33 trade-gallon containers with pure pumice

• 5 quarts – fills approximately 2.5 trade-gallon containers with pure pumice

• 3 gallons – fills approximately 6 trade-gallon containers with pure pumice

• 6 gallons – fills approximately 12 trade-gallon containers with pure pumice

Shipping Information

All prices include shipping.

• 15-ounce quantities ship First-Class.

• 10-cup and 5-quart quantities ship Priority Mail.

• 3-gallon and 6-gallon quantities ship UPS.

Storage and Handling

Our pumice is hand-packed in a bag with a reusable tie, making it easy to store after opening.

If the pumice dries before use, moisten it to help prevent dust from forming. Do not inhale dust from rock or potting soil products. Dust may irritate the lungs, particularly for people with sensitive respiratory systems.

Bring the benefits of natural volcanic pumice to your bonsai, cactus, succulent, and specialty plant soil mixes.