Plagron Promix - Organic Peat & Worm Castings Potting Soil

🌱 Type: Organic
Nutrients come from natural sources (like guano, worm castings, or plant matter) and are broken down slowly by soil microbes before your plant can use them. This makes it very hard to overfeed or burn roots, and it builds long-term soil life over time. The tradeoff: it acts more slowly than mineral feeds, and nutrient levels can vary slightly batch to batch since it's a natural product rather than a lab-blended formula.

Plagron Promix — The Organic Grower's Blank Canvas

Unlike Plagron's other organic soils, Promix arrives with no added nutrients at all — just a carefully selected blend of peat types and Plagron's own worm castings. The worm castings bring the soil to life and activate whatever organic fertiliser you add, but they don't feed your plant on their own. That makes Promix the choice for growers who want the safety and soil-life benefits of organic growing, with total control over exactly what goes in and when.

Why Growers Choose Plagron Promix

Genuinely Unfertilised, Genuinely Organic
Start fertilising from day one with an organic base nutrient (Plagron's own Alga Grow, then Alga Bloom for flowering). The low starting EC means young plants root in with minimal stress — no risk of a heavy pre-charge overwhelming a fresh transplant.

Rich, Light, Oxygenated Structure
A blend of different peat fibre types gives Promix a lightness and airiness that's a genuine Plagron hallmark, keeping roots well-oxygenated rather than sitting in dense, compacted soil.

Control Union Certified Organic
Genuinely certified organic cultivation — good for people, animals, and the environment, with the worm castings supporting real, living soil biology rather than just a marketing claim.

Naturally Gnat-Resistant
Growers who've used Promix consistently report less fungus gnat activity than with heavier, wetter composts — the light, airy structure simply gives gnats less of the damp organic matter they need to breed in.

One Honest Caveat: Not for Seeds or Cuttings

Plagron are upfront about this themselves — the same light, fibrous structure that makes Promix excellent for established plants works against delicate seeds and fresh cuttings, which struggle to pull moisture through it and can get physically hindered by the fibres as they emerge. If you're starting from seed or striking a cutting, reach for a dedicated seed and cutting mix instead, then move the young plant into Promix once it's established.

Who This Is Actually For

• Experienced Organic Growers: Anyone who wants to build their own feeding programme with Alga Grow, Alga Bloom, and Plagron's organic additive range from day one.
• Established Houseplants: Peace Lily, Pothos, Spider Plant, ferns, and other moisture-tolerant houseplants that are past the seedling stage and ready to grow on.
• Organic Edibles: Herbs, tomatoes, and container vegetables for growers who want full control over an organic feeding schedule.

As with any peat-based soil, it's a better fit for general houseplants than for rot-prone Aroids like Monstera or Alocasia, which do best in a chunky coco/perlite mix — Promix's strength is soil life and grower control, not aggressive drainage.

Technical Specifications:

• Composition: Peat blend, Plagron worm castings
• Fertiliser Type: None added — genuinely unfertilised, Control Union certified organic
• pH: 6.1 – 7.1
• EC: 0.4 – 1.1 mS/cm
• Recommended Feed: Organic base nutrient from day one (e.g. Alga Grow, then Alga Bloom)

📦 Please Note: Sample, 1L, 5L, 10L, and 20L sizes are carefully decanted from original manufacturer packaging into secure, unbranded packaging to offer flexible quantities for every project size. 50L options are supplied in the original sealed manufacturer bag.