Mr Hatchard said the retail side of the business was left untouched but it was a vital time for potting and planting, which must continue despite the fire.
"Our retail operation wasn't affected at all and our doors are open for business.
"But what we lost in the fire was basically the heart of the operation and this is our best time to be potting and planting to catch autumn growth," Mr Hatchard said.
"It's worth thousands to us and we just have to keep production going."
He said that yesterday GardenBarn production grower John Goodall was busy recalling potting formulas unique to the company that had been stored on a computer lost in the fire.
A makeshift shelter will now be built to continue the potting work.
Several out-of-town nurseries, Masterton businesses and the Mayor of Masterton Garry Daniell had offered the company the use of a forklift or a tractor, Mr Hatchard said.
And his granddaughter Jade Bradnock, 6, had pitched in, handing him a $20 note to help out.
"I'm not going to spend that $20 - it's special.
"So are all those people who have offered equipment and help," Mr Hatchard said.
"This is where you find out who your friends and supporters are and it's touching really that so many businesses, individuals and customers are being so kind."
Mr Hatchard said GardenBarn had undergone significant expansion and rebranding two years ago and he planned to rebuild on the same site another production, staff and storage facility with dimensions similar to the structure gutted in the blaze on Sunday.