Monro South, which has depots in Kent, Sussex and Cambridgeshire, is believed to owe as much as £4m to suppliers and other creditors. LBS Horticulture, BHGS and JFC Monro are also poised to take on affected customers.
Fargro commercial manager John Blunden-Codd said: "It's a very sensitive time. Everybody is waiting to see what happens. It's very sad that an established firm like Monro South has gone down.
"We're trying to cope with the aftermath at the moment. Hopefully, there will be no shortages. We have very good stocks and we're in a position to pick up the majority of that business if needed."
William Sinclair took over Monro South brand Growing Success recently, believed to have been transferred in lieu of debts to the compost company, although William Sinclair declined to comment on this.
Monro South ran the annual Southern Growers show, which is set to continue under the management of Roundstone Nurseries.
A Monro South source said the wholesale business was not to blame for the company's collapse, with retail businesses taking it down. He said debts were "less than £4m, but a lot". The company's creditors include compost and pot manufacturers.
Customer Kernock Park Plants business development manager Mark Taylor said: "Many people are going direct to manufacturers and there are fewer customers now. Running lorries with nothing on them is expensive."
Administrator Moore Stephens did not return HW's calls. The administrators are Simon Paterson and David McClean.