The magazine said while overall quality was good, some composts were "definitely better" than others - when growing potatoes, the best buy produced twice the yield of the poorest-performing composts.
Homebase secured two best buys - its grow bag was the best bargain bag, while its multi-purpose compost was top in its class. B&Q's John Innes No 3 was the best buy for minimum watering, while Westland West+ Advanced compost was top for reduced peat. New Horizon's Organic & Peat Free Growbag won the peat-free section.
For each brand, 12 pots of Impatiens were planted up. They were assessed for flowering and vigour between June and October. Potatoes were harvested in August and their yield and quality recorded.
Bags of each compost were bought from four different areas in the UK to test for differences in quality within the same brand.