Debra Creighton grows tomatoes in hydroponic tunnels on her property outside Taree in the NSW Manning Valley.

"I grow them all year round, but have more trouble in summer because they get heat stressed," she said.

"When you have those 32 degree days, in here it's like 43. It's too hot.

"They lose their flower, their heat stressed and the fruit just wants to ripen up the whole plant.

"So instead of growing slowly and ripening up down the bottom of the vine, they'll just ripen up the whole way up and you don't get any new fruit come on."

The crop is sold, along with other local produce, at the farm gate shop by using an honesty box system.