Orchid Nerd Sponge Rock (Perlite)
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- Backordered, shipping soon
Super coarse perlite, also known as sponge rock, for orchid potting mixes that need extra drainage and airflow.
Orchid Nerd Sponge Rock is horticultural-grade perlite in a super coarse particle size. It's lightweight and porous, adding air space to a mix while holding a small amount of moisture.
Choose a 1-cubic-foot box for routine home repotting or a 2-cubic-foot box for larger collections, frequent repotting, and greenhouse use.
Why Orchid Growers Use Sponge Rock
Sponge rock is commonly blended into fir bark or other orchid potting mixes to add drainage and air space. Because it's a mineral material rather than an organic one, it doesn't break down the way bark or moss eventually does, so it helps a mix stay open longer.
Product Highlights
- Super Coarse Grade: Coarse particles that support drainage and airflow
- pH range of 6.5 to 7.5
- Mineral material that does not decompose like organic potting media
- Two sizes: Available in 1-cubic-foot and 2-cubic-foot boxes
Product Specifications
- Grade: Super Coarse
- pH Range: 6.5 to 7.5
- Moisture Content: Less than 0.5%
Choose the Right Size
| Size | Recommended For |
|---|---|
| 1 Cubic Foot Box | Home growers, smaller collections, and routine repotting projects |
| 2 Cubic Foot Box | Larger collections, frequent repotting, orchid societies, and greenhouse use |
Best For
- Orchids that need extra drainage or prefer drier root conditions
- Blending into bark-based potting mixes to improve airflow
- Custom mix builders who want to control their own ratios
- Hobbyists, collectors, orchid societies, and professional growers
How to Use
Sponge rock is normally blended with bark or other orchid potting materials. The amount used depends on the orchid, pot, growing environment, and watering routine.
Frequently Asked Questions
Is sponge rock the same thing as perlite?
Sponge rock is a coarse horticultural grade of perlite commonly used in orchid potting mixes. They are the same base material, but particle size can vary between products.
Can I use sponge rock by itself?
Sponge rock is normally blended with bark or other orchid potting materials rather than used on its own. The right ratio depends on the orchid, pot, growing environment, and watering routine.
Which size should I order?
The 1-cubic-foot box is a practical choice for smaller collections and regular home repotting. The 2-cubic-foot box is better suited to larger collections, frequent repotting, orchid societies, and greenhouse use.
Does sponge rock break down over time?
No. It's a mineral material, so unlike bark it doesn't decompose over time.
Recommended Pairings
Selected With Growing Experience
Waldor Orchids has been growing orchids since 1925. Orchid Nerd supplies are selected with the practical needs of orchid growers, collectors, orchid societies, and greenhouses in mind.
We ship live orchid plants with care. All plants are carefully inspected, packed bare root or in pot, and shipped to arrive in excellent condition.
Please review our Important Plant Shipping Notice before ordering — it covers shipping windows, weather holds, and what to do if your plant arrives damaged.
