Bonsai Soil Mixtures

General Notes:

Using a coarser mix (for example: 3/8 to 1/4 inch with a large tree or 3/16 inch with a small tree) will stimulate more vigorous root growth in young or unhealthy trees. To avoid excess root growth and frequent repotting, use a finer mix.

Deciduous and broad leaf evergreens require more organic as opposed to confers that benefit from having more clay.

The ratio of different kinds of non-organic materials varies greatly based on climate, frequency of watering, personal experience, etc. The more water retention in the soil mix, the better, in hot or dry climates, but in very humid or wet climates, you want more drainage and less water retention. For the extremely hot and dry summers we have here, I have started using equal parts DG, Turface MVP, and Akadama for the non-organic. Sharp materials will cause the roots to divide more, whereas smooth materials will cause roots to lengthen more before dividing.

Organic materials should be steralized before using if not purchased commercially. A small amount (5%) of wood charcoal is also helpful to keep the soil mix healthy.

Reccomended Materials:

Gravel:

• washed sand
• decomposed granite (DG)
• lava rock
• pumice

Clay

• Akadama
• Turface MVP
• untreated cat litter

Organic:

• Amend (by Kellogg)
• N-Rich (by Kellogg)
• peat moss
• fir bark
• wood charcoal

Soil Mix Ratios

• 20% Organic to 80% Non-organic: Black Pine
• 30% Organic to 70% Non-organic: White Pine, Red Pine, Olive
• 40% Organic to 60% Non-organic: Juniper
• 50% Organic to 50% Non-organic: Cotoneaster, Pomegranate
• 60% Organic to 40% Non-organic: Cypress, Cedar, Elm Fushia, Hackberry, Holly, Hornbeam, Maples, Mume, Zelcova, Wisteria and Most Deciduous
• 70% Organic to 30% Non-organic: Bougainvillea, Ginkgo, Malus, Spruce, Yew, Azalea, Quince
• 80% Organic to 20% Non-organic: Cycas, Bamboo