In this episode of The Underground Podcast, Phil and Kate welcome back returning guest Scott Smith, who has just completed his thesis for the RHS Master of Horticulture (MHort). His subject? The hot topic of peat free compost, an issue that continues to challenge, frustrate, and divide gardeners and growers across the UK.
Scott shares insights from his self-funded, 14-week compost trial, comparing how different peat free products performed against traditional peat-based compost using Sungold tomatoes as his test crop. From nutrient lockout and NPK imbalances to the common mistake of overwatering due to dry surface layers, Scott’s findings are eye-opening for anyone navigating the peat free transition.
We talk about the challenges of standardisation, the need for clearer compost labelling, and the surprising results that saw B&Q Verve peat free compost outperform much more expensive brands. Whether you're a professional grower or a weekend gardener, this episode is full of practical tips, honest reflections, and some much-needed clarity around peat free gardening.
Highlights include:

• How Scott designed his home-grown compost trial
• Why NPK levels matter more than you think
• The risk of nutrient overload in certain peat free blends
• What compost brands performed best—and worst
• Real-world advice for switching to peat free with success
• What the industry needs to do next for gardeners to feel confident making the switch

Perfect for: Garden centre buyers, horticultural professionals, peat free product developers, and any gardener who’s ever asked: “Why won’t my plants grow in peat free?”

Your hosts:Phil Wright: ⁠⁠http://wrightobara.com⁠⁠Kate Turner: ⁠⁠http://www.gardenerguru.co.uk