Brand: Westland PF John Innes No1 | Supplier: B&Q | Price: £0.17/litre
Personal observations
John Innes No. 1 is the seedling formulation — lower nutrient level, finer texture, designed for young plant roots. This Westland version has visible fine sand throughout, as expected for a JI mix. One thing I was not expecting: visible white fungal growth on the inner surface of the bag when we opened it. This is most likely associated with a biochar addition — biochar can encourage fungal colonisation in the bag during storage, and the observation is consistent with that hypothesis. It is not a contamination problem, but worth noting. Two small fragments of white plastic and one stringy piece were also visible after sieving. Water retention is the lowest in the entire test group at 1.39 times dry weight — again, this reflects the sand/clay mineral fraction rather than being a performance issue for its intended use. Dry-down was the slowest of the JI products tested at 40 minutes.
Quick-test data (April 2026)
| Metric | Band | Value | Context |
|---|---|---|---|
| Bulk density (dry) | H | 0.36 g/ml | Heavy — highest mineral content in test group |
| Water held per g dry weight (WHC) | L | 1.4× | Low — lowest in test group; reflects sand/clay fraction |
| Dry-down time | — | 40 min | Slow for a low-WHC product — mineral surface behaviour |
| Sieve: <2mm fraction | — | 56.3% | Moderate-high fine fraction |
| Sieve: 2–10mm fraction | — | 29.2% | Low-moderate |
| Sieve: >10mm fraction | — | 7.3% | Low-moderate |
| Price per litre | Mainstream | £0.17 | B&Q retail — bought in store, no P&P |
Low WHC is correct and expected for a John Innes formulation — mineral content dominates the dry weight. Direct comparison with peat-free organic composts on this metric is not meaningful.
B&Q in-store price only — purchasing online adds delivery cost and is not recommended for bulk compost. For an explanation of why brands offer multiple product types at different price points, see our FAQ.
Comparative hands-on testing, April 2026. Consistent method across all 18 products. See methodology note.
At‑a‑glance rating breakdown
| Category | Weight | Score |
|---|---|---|
| Ease of use | 40% | 6.8 |
| Composition & quality | 35% | 6.8 |
| Sustainability | 25% | 6.8 |
| Overall (weighted) | 100% | 6.8 / 10 |
Contextual use modifiers
John Innes No. 1 is designed for early plant establishment, not as a general multipurpose compost. It provides controlled nutrition and structure during the first growth stages.
Strengths & limitations
What we liked
- Consistent, well‑understood formulation.
- Suitable for young plants and potting‑on.
Points to consider
- Heavier than most peat‑free MPCs.
- Sustainability profile varies by manufacturer.
Our conclusion
Overall impression: John Innes No. 1 remains a dependable choice for early growth stages, provided buyers verify the specific manufacturer’s formulation.
