Down to Earth Rock Phosphate 0-3-0 | 5lb - OMRI Listed - (Case of 6)

Soft Rock Phosphate for pH-Independent Long-Term Phosphate, 5lb Case of 6

Some phosphorus sources tie up and become unavailable outside a narrow soil pH window, which is a problem in beds that swing acidic or alkaline over time. Down to Earth Rock Phosphate 0-3-0, also known as soft rock phosphate or colloidal phosphate, is a natural, untreated mineral that stays available across a wide pH range and builds soil calcium alongside its phosphate content.

This 5lb bag, sold in a case of 6, suits home gardeners mixing Rock Phosphate into soil or compost before planting a new bed.

Key Features & Benefits

• Untreated colloidal phosphate — delivers phosphate from a natural, unprocessed rock mineral rather than a chemically treated source.
• OMRI Listed — cleared for use under certified organic growing standards.
• Available across a wide pH range — keeps supplying phosphate even in soils that swing more acidic or alkaline than average.
• Adds soil-building calcium — contributes calcium alongside its long-lasting phosphate content.

Who Should Use This

Gardeners establishing a new bed or worried that soil pH swings might tie up a treated phosphorus source are the right fit for Rock Phosphate, since its natural form stays available across a wider pH range.

About Down To Earth

Down To Earth includes natural mineral inputs like Rock Phosphate in its organic amendment lineup, part of a catalog built on natural ingredient sources since the company opened in Eugene, Oregon in 1977.

Frequently Asked Questions

What is soft rock phosphate, and how is it different from other phosphate sources?

It's also known as colloidal phosphate, a natural, untreated mineral form of phosphate rather than a chemically processed one. That untreated form is part of why it stays available to plants across a wider soil pH range than some treated phosphate sources.

When should Rock Phosphate be applied?

It's typically mixed into soil or compost before planting, so the phosphate and calcium are positioned in the root zone from the start. Follow current label directions for application rates by bed size.

Is Rock Phosphate 0-3-0 OMRI Listed?

Yes, this Rock Phosphate is OMRI Listed for certified organic use. Confirm the listing on your package against your certifier's current standards before relying on it for certified beds.

Does soil pH affect how well Rock Phosphate works?

Less so than with some other phosphate sources, since it remains available to plants across a wide pH range rather than tying up outside a narrow window. That's one of the main reasons growers reach for it over a treated phosphate alternative in variable soils.