Mark Fitzpatrick's store was destroyed after explosives lit up the sky at neighbouring Southern Firework Factory in Southampton on 13 May.
Hampshire Fire said plastic-wrapped cardboard boxes ignited after they were stacked close to a 300 watt lightbulb.
Mr Fitzpatrick said rebuilding the business was a priority.
He said he was "absolutely devastated" when he discovered the blaze at the family business on Bitterne Road West.
"When I was coming over the Itchen bridge , I saw the smoke and I began screaming. The business is my life. The feeling I got when I saw the shop ablaze was absolutely horrendous - a feeling I never want to experience again," he said.
No-one was injured during the incident but homes and properties within 100 metres (328 ft) of the fire were evacuated. Bitterne Manor Primary School was also closed.
"There was just nothing I could do. It was gone. We were just lucky that nobody got hurt."
Mr Fitzpatrick's daughter, Jessica said she feared her father would suffer a heart attack following the "emotional rollercoaster".
"We have lost a lot - including three olive trees worth Â£2k each. The fixtures and fittings also need to be replaced. I don't know how much the clean-up bill will be - but it will be a lot."
The family said they have set up a market stall in Southampton but hope to rebuild the store "as soon as possible".

The 29-year-old centre-back turned his left ankle during the second half of last Saturday's 4-0 win over West Brom.
"When your mind is positive it's easier to recover," said the Argentine boss. "He doesn't require surgery.
"We have players that can perform in his place and we are very happy with the squad and the players we have."
Analysis: The best defence? the most powerful midfield? - How good are Tottenham?
Vertonghen has played in 20 out of 21 league matches this season, forming part of a defence that has conceded just 14 goals - the best record in the league.
Pochettino, however, was unsure as to when attacking midfielder Erik Lamela would return to action. The 24-year-old has been sidelined since the end of October with a hip problem.
"He will have a scan on Friday," he added.
"Still it is difficult to give the time that he can come back. We need to wait tomorrow because there is still some problems, and we are still not sure of the diagnosis."
A florist whose business was destroyed in a fire which set off explosions at a neighbouring fireworks factory has pledged to rebuild his business.
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Tottenham defender Jan Vertonghen is expected to be out for six weeks with an ankle ligament injury, according to his manager Mauricio Pochettino.