Volunteers at the Waterloo Street Arches garden in Hove say people “use it like a toilet”, smash plant pots and tear plants out of the ground.
A recent rise in problems has been linked by residents to the closure of a nearby homeless shelter.
Brighton and Hove City Council refuted the claim, saying there was “no evidence” to say it was linked.
One volunteer at the garden, who wished to remain anonymous due to fear of violence, said: “They’ve got knives and all sorts stashed round here. Some bloke walked through with a full syringe.
“It’s senseless damage. They are lawless, they use it as toilet.”
Another said: “It’s heartbreaking. I felt physically sick when I saw the damage.”
Residents said the garden, which is near The Old Market theatre, has been blighted by antisocial behaviour for years.
The garden, part of which was originally funded by Angus, Thongs and Full Frontal Snogging author Louise Rennison, is run entirely by volunteers.
They said problems have got worse since the closure of the St Patrick’s Night…
