After being arrested by armed police at his home in Mundella Road, Nottingham, John Kinsella, 48, took officers to the southern suburb of Wilford, it was claimed.
He indicated a corner of the allotment and six inches below the surface police discovered a bag containing Semtex explosive, guns - including a sawn-off shotgun - detonators and components of bombs, the court was told.
At his home, the jury was told, police found a blank English marriage certificate, a radio scanner tuned to local police stations and a book called The Irish Hunger Strike.
Bernard Curtis, who rented the allotment from the council, told the court that he had been a friend of Mr Kinsella, known as 'Dublin John', for more than 30 years.
He said he had done him many favours and was a good friend. When Mr Kinsella had asked if he could store gear - roof tiles and window frames - at the allotment, he had been happy to let him.
He also agreed to his request for a small patch on the allotment to grow flowers and vegetables.
Cross-examined by Helena Kennedy QC, for the defence, Mr Curtis said that his friend was 'a very good chap'. He repeatedly denied knowing that Mr Kinsella was involved in handling stolen property.
But he agreed that he had once found something in the allotment shed which 'did not suit, and I told him get rid of it. I was not happy about it'.
Mr Kinsella was arrested when police surrounded his home two days after bombs planted by an alleged IRA active service unit exploded at the gasworks in Warrington causing a huge fireball. Some of the devices did not go off and others failed to puncture the gas holders.
On Mr Kinsella's arrest, the court has been told, he had asked police: 'What is all this about?' In later interviews he said he had agreed to bury the bag, thinking it contained stolen candelabra. He denies possessing Semtex with intent.
His nephew, Denis Kinsella, 27, of Nottingham, and Pairic MacFhloinn, 40, of Dublin, deny causing an explosion and charges of attempted murder of a PC, assault, kidnapping and possessing a firearm. A third member of the group allegedly escaped.
The trial continues today.