According to the police summary of facts, the staff managed to put the blaze out before it could spread but the store was evacuated and subsequently closed for the rest of the night.
The clothing was destroyed and the metal rack was damaged.
He also stole various items including perfume, glasses, clothing and shoes valued at $1925 from local stores between December 12 last year and January 18.
This included Adidas-branded shoes and clothing from the Rebel Sports store in Chapel St valued at $645, after twice visiting the store on Boxing Day and on December 28.
Lawyer Jeremy Sparrow urged Judge Macdonald to impose home detention, submitting that his client had previously served such a sentence without incident.
Sparrow said Heke's crimes were drug-related and he was genuinely motivated to undertake any counselling offered to him to address the causes of his offending.
Heke had been in custody since May 8, and his letter of apology showed he was remorseful for his actions, he said.
Judge Macdonald urged Heke to explain to him the reason for committing the arson in particular, but despite several requests, Heke struggled to do so.
Judge Macdonald said the starting point for Heke's "rather bizarre behaviour" relating to the arson and offending had to be imprisonment, particularly given his "extensive criminal history" that included 19 prior convictions for theft and three breaches of community work.
Judge Macdonald told Heke that by the narrowest of margins he was prepared to impose eight-months home detention, with 6-months of prison release conditions.
He warned Heke to strictly adhere to the terms of his sentence and urged him to take full advantage of the opportunity to try and turn his life around.
Judge Macdonald said he hoped Heke was motivated to do so, but given his past criminal behaviour, he would not be "holding his breath".
Heke was ordered to pay $4425 reparation and disqualified from driving for six months.