Brand: Miracle Gro PF, All purpose | Supplier: B&Q | Price: £0.17/litre
Personal observations
The All Purpose version is visibly different to the Moisture Control product sold alongside it. Lighter, more wood-fibre-led, and with noticeably more material retained above 10mm — nearly 10% of the sample, which is at the higher end of the test group. What sits on the sieve is almost entirely fibre fluff rather than woody fragments or aggregates. Water retention drops to 2.6 times dry weight — a meaningful step down from the Moisture Control formulation. Dry-down is faster at 20 minutes. The two Miracle-Gro products together make an interesting comparison: the Moisture Control appears to use a richer, heavier input mix, while the All Purpose relies more on wood fibre for structure. Both are sold at the same B&Q price point. If you are choosing between them, the Moisture Control is the better performer for containers and hanging baskets. The All Purpose is more of a general growing medium.
Quick-test data (April 2026)
| Metric | Band | Value | Context |
|---|---|---|---|
| Bulk density (dry) | M | 0.18 g/ml | Mid-range — typical wood-fibre product |
| Water held per g dry weight (WHC) | M | 2.6× | Typical organic range — standard fibre binding |
| Dry-down time | — | 20 min | Fast — water not strongly retained |
| Sieve: <2mm fraction | — | 50.0% | Moderate fine fraction |
| Sieve: 2–10mm fraction | — | 35.6% | Moderate |
| Sieve: >10mm fraction | — | 9.8% | Moderate-high — noticeable coarse fibre fraction |
| Price per litre | Mainstream | £0.17 | B&Q retail — bought in store, no P&P |
High WHC likely assisted by a wetting agent — consistent with the product positioning and the notably wet condition at bag opening. The 30-minute dry-down confirms the water is genuinely accessible to plants rather than being purely structural capillary retention. Better real-world moisture behaviour than the dry BD alone would suggest.
B&Q in-store price only — purchasing online adds delivery cost and is not recommended for bulk compost.
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% | 6.7 |
| Composition & quality | 35% | 6.7 |
| Sustainability | 25% | 6.7 |
| Overall (weighted) | 100% | 6.7 / 10 |
What we liked
- Easy to use.
- Widely available.
Overall impression: Feels like another ‘wood fibre’ based compost.
