John Fagan, 64, of Watson Road, Worksop, pleaded guilty to fraud and dishonesty at Nottingham Crown Court and received two years for the first offence and 18 months for the second, the sentences to run concurrently.
The time period of the offences was between November 2009 and October 2010.
However, it was believed he had been taking money for much longer than that.
The business he defrauded was Northern Garden Supplies and Northern Swimming Pools, both owned by June Richardson, who first founded the garden centre business with her late husband Derek almost 40 years ago before later expanding to swimming pools.
Mrs Richardson and her family were in court to hear the verdict and afterwards expressed their delight at what they saw as justice done.
“We delighted at the verdict and that mum has had her day in court to see justice done,” said Mrs Richardson’s daughter Sally.
“We believe he had been taking money from the business for 10 years and we know we’ll never see any of that money back.”
“The main thing we wanted was to see him brought to justice for it because it was not just the fraud we didn’t like about him, it was the way he groomed mum to turn her away from us and on to believing anything he said and made her think he was the only one she could trust.”
The court heard that Fagan had been employed by Northern Garden Supplies virtually from the time it was set up and rose from being the handyman to being in charge of finances and running mainly the swimming pool side of the business after Mr Richardson had died.
Prosecuting, Mr John Fountain said: “Despite Mr Fagan having a history of previous sexual offences, Mrs Richardson was prepared to give him a chance and he became less of an employee and more a member of the family.”
“She even bought him a new caravan to live in and paid for him to have a foreign holiday.”
Fagan eventually took over the running of both sides of the business but the garden centre soon began to struggle financially.
However, he convinced Mrs Richardson the struggles were legitimate and convinced her pump thousands of pounds of her own money into propping up the garden centre.
In 2010, Fagan switched his attention solely to the swimming pools side of the business abut still had access to the tills and finances of the garden centre.
Still, the garden centre struggled as suppliers and staff went unpaid, and the accountants and book keepers began to ask questions.
Eventually, an investigation took place and found that there had been numerous payments made to Fagan, or to an account on his behalf.
The accountants found a diary that Fagan had kept detailing all payments that had been made so that he could cover his tracks.
Fagan tried to block the investigations by changing computer passwords but eventually it became clear that thousands of pounds had gone missing with Fagan even creating false payment notices and documents down the penny to try hide what was happening.
When first questioned by police, Fagan claimed he was being blackmailed but this has been strongly denied by the alleged blackmailer.
“Even considering that, it still only amounted to £30,000 and that still leaves £28,000 unaccounted for,” said Mr Fountain.
Defending, Mr Jonathan Straw said: “It is not the case that he used the money to live the high life or fund an addiction, it went straight to another source that he maintains was blackmail.”
“However, he accepts he did not go about things the right way and that he has caused June Richardson considerable stress.”
Passing sentence, the judge His Honour Michael Stokes, Recorder for Notts, said: “Your conduct towards Mrs Richardson, after she gave you a chance, has been described as a betrayal and that is the appropriate word, betrayal.”