Crop guides · Guide
Epsom salt for roses: does it work? Usually not
Epsom salt for roses is one of the most repeated tips in British gardening, and one of the least supported by trial evidence. It helps on...
Allotment gifts for Christmas
Feed sets and gift cards growers actually use. Shop allotment gifts
The Dr Forest blog · Est. Stockport · England · 2020
Soil science & growing guides, properly explained.
Evidence-led guides to organic fertiliser, feeding and soil science for UK growers. Deficiencies, ingredients, biostimulants and crop-by-crop feeding, with every claim checked against the original paper.
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beginners guide · Guide
Organic vs chemical tomato feed: taste or yield?
After fifteen years cooking professionally, I could taste how a tomato had been fed. The head-to-head on flavour, yield and soil, with the science behind it.
basalt · Guide
How volcanic rock dust works, and how slowly
Volcanic rock dust supplies silicon and over 60 trace minerals: the elements NPK fertilisers leave out. Here is the chef-and-soil-science case, plus the peer-reviewed evidence on...
boubly mine · Guide
What is polyhalite? 4 nutrients in one crystal
Polyhalite is a single mined crystal carrying potassium, calcium, magnesium and sulphur. Four nutrients from one scatter, low chloride, from the Boulby mine under the North...
Epsom salt for tomatoes · Guide
Tomato leaves turning yellow? 6 signs to check
Tomato leaves turning yellow usually name a cause once you know where the colour starts. Finger in the compost, then read the leaf: bottom, top, or...
mycorrhizal fungi · Guide
What are mycorrhizal fungi? The plants they skip
Mycorrhizal fungi are tiny soil fungi that live in and around plant roots. They spread fine threads through the soil and bring back water and phosphorus,...
17 essential nutrients · Guide
What is a fertiliser? What it does and how to read the bag
A fertiliser supplies one or more plant nutrients in a known amount. Seventeen essentials, how to read the NPK on the bag, and when an organic...
essential oil herbs · Guide
Zinc deficiency in plants: check the new leaves
Zinc deficiency shows on the newest leaves first: small, bunched, pale between the veins. It is rare in UK garden soils. Test before you treat; too...
Soil science · Guide
How to top dress: 2 g per litre, 100 g per m²
By Joe Barrington, founder of Dr Forest · Published October 2024 · Updated 6 November 2026 Quick answer. How to top dress pots and beds: scatter...
The garden journal
Feeding schedules, soil science & 10% off your first order.
One letter a month on what to feed, when to feed it, and why it works. Written by Joe, for growers who want to understand their soil.