Volunteers arrived at Milton Community Garden at Liddesdale Square yesterday morning to find the burnt out digger, as well as destroyed seating and tyre decorations.
Police are hunting for the firebugs behind the latest round of vandalism, which has left the community shocked.
In September 2012, the Evening Times told how their greenhouse was burnt down and shipping container with garden tools were wrecked, just over a year after it opened.
Later that month the vandals returned and set fire to the garden again.
The community had been rebuilding their hub since then, helped by a £1500 grant from our Streets Ahead fund.
The group hired the digger to lay the finishing touches - but now fear they will have to pay for the damage.
Volunteer Liz Rennie, from north Glasgow, said: "I am shocked and angry, it is an outrage. They were obviously trying to make the fire spread to the whole garden."
The blaze started at about 1.30am yesterday.
Ms Rennie, 64, said the vandals don't realise this is their garden. She said: "They don't realise the word community includes them."
But residents in the north of the city remain defiant.
Ms Rennie said: "It is a lot of work to rebuild it but we will. We have got to stand up for ourselves."
Project co-ordinator Roland Playle, from the North Glasgow Community Food Initiative, which manages the garden, said: "It's probably about £10,000 worth of damage.
"We're just trying to work out if insurance will cover it.
"We're a charity so don't have that sort of money.
"We were getting to the stage of completing after four years of back breaking work."
Another volunteer Colin Stewart, 64, said: "It's horrendous what they've done - yet again. It really is sad but we'll keep at it. I lost my wife three years ago and since then I've always come up to spend time here and help out.
"There is a whole bunch of great people round here."
A spokeswoman from Police Scotland said: "At around 1.30am police received a report of a digger on fire.
"It is being treated as wilful. Inquiries are continuing."