By Michael McHugh, PA.
Garden centres were reaching a critical tipping point without decisive action, environment minister Edwin Poots said.
They will reopen from Monday as the Executive takes its first tentative steps towards recovery from restrictions imposed to limit spread of coronavirus.
Spring is the peak period for horticulture sales, and many of the plants could have been wasted if the shutdown had continued.
Mr Poots said: "The horticulture sector was reaching a critical tipping point, as sales crashed and profits plummeted - with only a very short trading window for summer bedding plants.
"Allowing people to visit garden centres while remaining safe will provide a much-needed injection of cash to these businesses that will help the future sustainability of the local industry."
He continued to ask people to leave the house as little as possible.
He said: "We must also give them the opportunity to be productive at home.
"As we move out of the spring months and into summertime, people want to get their garden into bloom so they can enjoy their outdoor spaces."
Robin Mercer, owner of Hillmount garden centre near Belfast, said the family business had been working hard to ensure all necessary signage and screens were in place.
He added: "We have been inundated with customers phoning, emailing and messaging us on social media asking when we are going to be open so I know that there are a lot of people planning to come and visit us.
"We are grateful for this as we have thousands of plants with a short shelf life that have been lovingly grown by growers here, in England and Holland, just waiting to be taken home."
Household recycling centres will also be allowed to reopen following a decision at Stormont's Executive meeting on Thursday.
Mr Poots added: "I would now urge councils, who have yet to do so, to re-open their household waste recycling centres as soon as is safely possible.
"This will allow people to recycle and dispose of their household and garden waste appropriately and responsibly.
"Irrespective of the pressures of the current crisis, the increase in fly-tipping recently observed in our countryside has been inexcusable and must stop.
"It has polluted and damaged our local environment."