Upheld

The ASA noted the claim was based on the results of two independent trials.  We noted the in-house trial reports which had been provided as supporting information but considered that, because the claim in the ad was based specifically on the results of "independent trials", we could not take in-house trial results into account as evidence for the claim.

We noted the independent trials had been conducted on a number of different peat-free and non peat-free composts, including a few variants of Scotts' own peat-free compost and two other peat-free composts produced by the two companies Scotts had identified as key competitors.  We understood from the data that the plants grown using the variant of Scotts' product which was on the market at the time the ad was published performed the best in measures of plant height and size, compared to plants grown using the peat-free composts produced by other companies.  However, we noted that the trials examined the performance of the composts when growing tomatoes and petunias only.  We considered that, because the claim "independent trails [sic] prove that Miracle-Gro Organic Choice Compost grows plants bigger than leading peat free products!" was preceded by the claim "it is proven to grow stronger, healthier plants, fruits and vegetables", consumers would understand that the product had been tested by growing a range of fruits and vegetables as well as plants more generally.  Because the trials were limited only to growing tomatoes and petunias, we concluded the results did not substantiate the claims, and consequently the ad was misleading.

Notwithstanding the above, we noted the claim made a comparison between Scotts' peat-free compost and "leading peat free products", and therefore concluded that the independent trials should have included all leading peat-free products.  We considered that, in the particular context of the ad, consumers would be likely to understand "leading" to mean 'best-performing'.  We understood Scotts considered that the 2010 Which? reviews demonstrated that they had included best-performing composts in the independent trials.  We noted that seven different peat-free composts had been included across the three Which? tests and that two of those composts had been included in the independent trials commissioned by Scotts.  We noted that the performance of those two composts varied in the Which? tests, and that other composts which had performed better or similarly had not been included in the independent trials commissioned by Scotts.   We considered the evidence provided did not substantiate that all best-performing peat-free products had been compared in the independent trials on which the advertising claim was based.

Furthermore, we noted that even if consumers understood "leading" to mean 'best-selling', we had not seen evidence that all best-selling peat-free products had been included in the independent trials.  We understood that the sales data from the market research group showed the sales of all types of compost, rather than specifically showing the sales of peat-free compost.  We were therefore concerned that the selection of comparator "leading" products to be included in the independent trials was not based on sales data relating specifically to peat-free composts, which we understood equalled a relatively small proportion of total compost sales.  We noted Scotts' explanation as to why there was no sales data specifically for peat-free composts but we considered that in the absence of sales data relating to all peat-free composts on the market, a comparative claim relating to "leading peat free products" could not be substantiated because it could not be demonstrated that all best-selling peat-free composts had been compared.

The ad breached CAP Code (Edition 12) rules 3.1 (Misleading advertising), 3.7 (Substantiation), 3.33 (Comparisons with Identifiable Competitors), and 3.38 (Other Comparisons).