Michael Young demanded £50,000 from Low Fulney grower David Bowman warning that he had injected the farmer’s pumpkins with deadly potassium cyanide.
Young struck just a week before Mr Bowman’s business was about to harvest the crop for sale.
Stuart Lody, prosecuting, said: “There is no evidence whatsoever that cyanide was ever used. The pumpkins contained water.
“The defendant sent photographs of pumpkins being injected with a substance and articles about potassium cyanide obtained from the internet.
“A letter said that the pumpkin crop had been selectively poisoned and warned Mr Bowman not to attempt to harvest or sell a single pumpkin until the blackmailer’s demands were fully met.”
Young demanded payment within seven days in Bitcoins.
Mr Lody said: “Mr Bowman’s immediate reaction was to call the police. One inquiry led to another and that led to the defendant.
“During the course of his interview he denied the offence and sought to point the finger at two East Europeans who had access to his computer.”
Tests later revealed that Young had actually injected a number of pumpkins with water but despite that Mr Bowman was forced to plough up a field of pumpkins losing £120,000 worth of stock.
In a victim impact statement Mr Bowman said: “I’ve had sleepless nights worrying how this callous and malicious crime will impact on my business.”
Young (53), of Alfred Street, Boston, appeared at Lincoln Crown Crown when he admitted a charge of blackmail between September 1 and 5 this year. He also admitted two charges of possession of drugs with intent to supply in 2011.
Mr Lody said that crack cocaine and heroin were found in Young’s home when police raided the property. Afterwards Young jumped bail and left the country to live in Germany for several years before returning to the UK.
Judge Michael Heath, passing sentence, told Young: “The sentence I am going to pass on you contains an element of deterrence. Let anyone who is minded to do the sort of thing that you did realise the sort of sentence that will follow.”
Michael Cranmer-Brown, in mitigation, told the court: “The offence concerning David Bowman is quite hard to understand.
“He is extremely sorry. There was no actual contamination of any of the crop. Water was the only matter that had been injected.
“He had been living in temporary accommodation in a multiple occupancy house. He was in dire financial straits. He had nothing to his name and he was on his uppers.”