More than 80 common pesticides and weed killers available over the counter in Northern Ireland are being banned from sale from the end of this week.
BBC Northern Ireland environment correspondent
It is part of a European Union directive to remove hazardous substances from gardens and farms and to harmonise pesticides across the EU.
But while most garden centres and retail outlets are aware of the Friday deadline, few consumers or gardeners know of the ban or what it covers.
Few consumers or gardeners know of the ban or what it covers
They must not use any remaining supplies after the end of December and must have disposed of all illegal pesticides by the end of March next year.
That is going to be a major problem for local councils.
They are obliged by law to accept and dispose of such chemicals, but so far they have received no instructions.
Councils the BBC spoke to on Tuesday were surprised by the legislation and are awaiting guidance from the Department of Environment.
They in turn are awaiting instructions from their sister department, DEFRA in London.
A bizarre twist is that some of the banned chemicals will simply return to the shelves re-packaged.
The instructions will have been changed to advise that the chemicals cannot be used on plants any more. For example, the product Armillatox will remain on sale but with the warning "Plant Protection Uses Only Withdrawn".
Faced with a list of over 80 chemicals, many gardeners will be baffled as to what is and is not legal.
They could be breaking the law after March next year.
The best guidance is that if it is not on the shelves in your garden centre next week, it is probably not legal.
They could also check the list on the special Pesticides Safety Directive site.
Getting rid of the banned material is an added problem.
People are being encouraged not to pour the chemicals down the drain or the toilet.
They should not throw it in the bin, as it could contaminate the landfill site.
Instead, they are being encouraged to take it to their council utility site and hand it over.
But they will probably be met by a blank stare until someone tells the councils what to do with all the chemicals.
Nursery centre worker Trevor Mercer said they were recommending customers to get in contact with their local councils before disposing of the chemicals.
Mr Mercer said other products would be re-labelled.
"One particular product, the Cutlass, is going to disappear completely, so you're going to have to get the hedge clippers out instead in future," he said.