From 4 April, the company will reduce its use of peat by 95% across its UK bedding plant range. It will aim to make these products fully peat-free next year.
Peat is an aid used by the horticulture industry to grow potting plants. It releases large amounts of carbon dioxide into the atmosphere when harvested.
Tesco is one of the largest sellers of bedding plants in the UK, selling around 40 million plants a year.
The retailer has partnered with Lincolnshire-based ornamental plant supplier Bridge Farm Group for the new initiative.
It also seeks to reduce its peat use by nearly 9,000m³ a year, which is expected to reduce its annual carbon emissions by more than 1,200t.
Tesco horticulture category buying manager Alex Edwards said: “This move is a major step forward in delivering a more sustainable plant range to benefit the planet.
“In collaboration with our supplier, the Bridge Farm Group, we have taken the decision to reduce peat at the earliest opportunity as part of a wider sustainability programme to reduce our carbon footprint.
“We hope to see a positive response from customers – many of whom talk to us about their growing concerns surrounding the sustainability of our planet.
“In taking the first step, we hope others in the horticulture market will follow, helping us find solutions for the plants and shrubs where we don’t yet have a viable alternative for peat.”
For its British bedding plants, Tesco will replace peat with alternatives such as wood fibre and organic by-products grown by the Bridge Farm Group.
The company aims to become peat-free across its compost range by the end of this year.
Earlier this year, Tesco announced plans to end the operations of its Jack’s discount chain stores.