Trade and Government representatives say legionnaires' disease warning labels remain unnecessary on bags of compost despite calls for stronger warnings on packs.
Margaret Murphy's husband Andrew died from leukaemia in 2014. His immune system was left weakened after he contracted Legionella longbeachae from compost in 2008.
Between 2008 and 2013, a total of 16 people in Scotland contracted legionnaire's disease from compost made from green waste. Two of them died.
"We have to have warning labels," said Murphy. The manufacturer of the compost paid her compensation in an out-of-court settlement.
In 2013, a University of Strathclyde study into 22 different compost brands sold in the UK found that 14 of them contained a variety of Legionella species. The research also found that four contained Legionella longbeachae.
A report produced by Health Protection Scotland (HPS) last year recommended that bags should warn gardeners to wear a mask if the compost is dusty because infection can occur when spores are inhaled.
A Growing Media Association (GMA) spokesperson said: "The GMA would like to reassure garden centres and their customers that the risk of infection remains extremely low.
"This was confirmed by a recent report by HPS that recorded less than one case per million population between 2008 and 2012.
"Compared with the number of gardeners in Scotland and the volume of growing media used, the HPS report concludes that the risks of severe disease are very low."
The Scottish Government and the HPS both said they are against labelling but would encourage anyone using compost to wear gloves, use a mask if it is dusty and wash their hands thoroughly afterwards.
HTA chief executive Carol Paris said: "We'd promote that people should wash their hands. I don't know that case but in most instances people are not well anyway. I don't believe there should be a legionnaires' warning label because I don't think people necessarily understand that."
On suggestions that the case would lead to an increase in peat use, she added that the issues are "two different arguments".
Peat demand - Retail market breakdown
One-sixth of people want peat-free products, one-sixth want pure peat and the rest are indifferent, according to Simon McArdle, marketing director at William Sinclair Horticulture, which produces the J Arthur Bower's compost brand.
He added: "A legionnaires' disease warning on bags is not commensurate with the risk. A weight warning would be more prominent in risk assessments."
McArdle said Sinclair has "damaged its reputation" by substituting peat with "not retail-ready products that had not been processed as long as they should be" supplied in 2013-14 following a peat shortage caused by wet weather in 2012.
Meanwhile, William Sinclair Horticulture is closing plants to relocate at its new £50m base in Cheshire, with almost 100 job losses proposed.