Brand: Rocket Gro MPC | Supplier: Amazon | Price: £0.30/litre
Personal observations
RocketGro, like many others, have a dozen or so composts in its range. I’m not a fan of this approach – see the link! I have met the team at various trade shows over the years. I chose this item as it seemed to represent what they do best: green waste and farm manure conversion to compost. This compost is noticeably darker than many others tested, which is consistent with the source materials used. The colour immediately suggests a well-humified material rather than a wood-fibre growing medium. It forms a reasonably cohesive ball in the hand, slightly sticky, with a neutral earthy smell and no contamination visible. No obvious woody fragments at all. The sieve result shows a fine-dominated profile: nearly 59% below 2mm, with the rest in the mid-fraction and nothing above 10mm. This is a well-processed product. The dark colour and cohesive texture suggest genuine composting inputs rather than wood-fibre processing. At £0.30 per litre online it sits in the mainstream bracket, though in-store equivalents of similar quality would be cheaper. The test data supports the product positioning: this behaves more like a traditional compost than many of its competitors.
Quick-test data (April 2026)
| Metric | Band | Value | Context |
|---|---|---|---|
| Bulk density (dry) | M | 0.22 g/ml | Mid-range — typical mature organic |
| Water held per g dry weight (WHC) | M | 3.1× | Mid-range — consistent with humic/digestate binding |
| Dry-down time | — | 20 min | Average |
| Sieve: <2mm fraction | — | 58.7% | High — well-processed, fine profile |
| Sieve: 2–10mm fraction | — | 42.2% | Moderate |
| Sieve: >10mm fraction | — | 0.0% | Negligible — very clean |
| Price per litre | Mainstream | £0.30 | Online via Amazon — P&P included in price shown |
WHC in the expected range for a digestate and PAS100 green waste blend — water held by humic and organic matter binding rather than structural trapping. The dark colour and cohesive hand-feel are consistent with a well-humified material. Reliable, predictable seasonal behaviour expected.
Price includes P&P — online only. Also available from the manufacturer direct. Comparable quality products at mainstream garden centre retail would typically be £0.18–0.25/l in store. For an explanation of why brands offer multiple product types at different price points, see our FAQ [link].
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% | 8.0 |
| Composition & quality | 35% | 6.5 |
| Sustainability | 25% | 7.7 |
| Overall (weighted) | 100% | 7.6 |
What we liked
- Familiar texture and behaviour for long-time gardeners.
- Robust UK sustainability story based around recycling local green waste and farm manures.
Summary: I like this one. If nothing else, it demonstrates the quality that can be achieved using the PAS100 ‘large scale’ composting process.
