The pressure groups' research found 19% of 1,300 products on sale were clearly labelled peat-free, but said there was a lack of choice, price incentives or labelling.
Growing Media Association chairman Steve Harper responded: "Peat-free supply to the market is actually over-indexing against demand. If the market is only 10% of sales but the research shows nearly 20% of the products were clearly marked peat-free then it shows the market is trying to drive peat-free sales."
He added that "the choice is there" because plenty of products are not obviously marked peat-free but are on offer.
He said almost every manufacturer and retailer stocks at least one peat-free alternative to multi-purpose and "given that 70-80% of consumers buy this product a very large percentage of anyone looking for a peat-free growing media is catered for.
Harper said some manufacturers don't highlight products as peat-free "because they don't want to put of consumers who don't want peat-fee and actively make a purchasing choice against it".
He said products that used to be peat-based such as soil improvers are now almost exclusively peat-free and manufacturers don't see the need to highlight that they are peat-free.
Mulches are also peat-free but not labelled as such: "In short, the choice is there."
Bagged retail peat-free has risen from 5.9% to 9% between 2011-15, according to figures the groups quote.
Half of the UK's peat is from Ireland and 7% comes from elsewhere in Europe. The pressure groups say the rest comes from Scotland, England and Northern Ireland.
Sandra Bell, Friends of the Earth campaigner, said: "Gardeners have a key role to play in buying peat-free compost – and in asking for more choice and promotion by retailers. This survey highlights a clear need for faster and more determined action by the garden industry and retailers to meet the UK government’s commitment to phase out peat use from amateur gardening by 2020."
Meanwhile, a £10 million grant scheme to restore England’s iconic peatlands has been launched by the Government.
Peatlands cover 11 per cent of England’s landscape.
The £10 million will be available for wildlife trust and charity projects to re-wet mosses, bring back missing plants and restore habitat. This is in addition to the £4 million Defra has allocated to existing Natural England peatland restoration schemes in England.
Environment Minister Thérèse Coffey said: "Peatlands are an iconic aspect of the English landscape which are not only a haven for wildlife but also provide us with clean water and help reduce greenhouse emissions.
"This funding will help restore thousands of hectares of this precious habitat to its natural state and is a key part of our ambition to be the first generation to leave the natural environment in a better state than we found it.
Natural England Chairman Andrew Sells said: "Peatlands are one of the most important resources in England for wildlife and people. They are our answer to tropical rainforests, storing hundreds of thousands of tonnes of carbon a year, providing clean drinking water, beautiful landscapes and valuable wildlife habitats, as well as reducing the risk of flooding.
"This investment will support practical restoration initiatives such as rewetting and seeding with Sphagnum mosses, an essential ingredient in restoring our peatlands for future generations.
"In addition to this, plants and animals unique to this habitat, including the white-faced darter dragonfly and round-leaved sundew, will be better protected for years to come.
"The funding will be available for projects that restore upland and lowland peatlands to their natural state, increasing their capacity to prevent carbon entering the atmosphere, reduce flood risk by slowing the flow of rain water and create habitats for vulnerable wildlife.
"The scheme will open in May and funding will target sites with the greatest potential for greenhouse gas reduction. Projects that deliver better value for money and maximise environmental benefits will be favoured for funding."
Funding will be available for three years from April 2018 as part of Defra’s £100 million of capital funding for direct investment in projects that support the natural environment. More details, including how to bid for grants, will be provided when the scheme opens for bids.