Fruit and vegetable growers are worried that lack of sunshine is harming the quality of their produce and lowering its value.

In July, Auckland had only four days without rain and growers say the lack of daylight is causing a major drop in production. They believe it is time to consider more resilient planting methods.

For more than a decade, Earl Mardle has grown most of what his family consumes at his property in Bombay, south of Auckland.

However, in recent months, he has noticed a change in the quality of his produce.

"Our olive trees flowered beautifully in spring; it was the best flowering I've ever seen.

"But when I came to press it, and I squeeze every last drop of olive oil I can from the fruit we get, I got about 12 or 13 litres of oil from 150kgs of olives, when I would normally expect 17 [litres]."

The reduced yield is not restricted to his olives.

"The same kind of thing happened to my kumara. This year they were extravagant, they grew like crazy.

"But, when I came to harvest, what I found was that the tubers were half, if that, the amount of tuber that I would expect."

Earl says people might need to rethink what they are growing.

"What kinds of food can we grow that goes with the type of climate that we are starting to see?

"I don't know how we are going to deal with that, but if we don't, we are going to go hungry."

Hawi Winter has lived in the rural Auckland community of Pukekawa for 33 years, where he grows more than 200 varieties of fruit and veggies.

He says this year's crop is the worst he has seen in decades.

"The apples ... we had a very poor crop, most of the apples didn't get as big as we are used to.

"Likewise, grapevines didn't like it [the lack of sun] that much. Same with kiwifruit, we didn't get many of them, and avocado, same story, we had very few avocados this year."

'Good follows bad'

Produce experts warn the prolonged low light and heavy rainfall could create a shortage of fresh fruit and vegetables.

United Fresh president Jerry Prendergast says tomato growers are struggling to get their winter crop thriving.

"A lot less crop available, compounded by low light and growing challenges.

"As a result of that, there was a lot less planting and getting those back to a cycle again, that doesn't happen immediately. It is a nine-month growing process."

The New Zealand Tree Crops Association is a voluntary organisation promoting interest in useful tree crops.

National president David Whyte says sunlight is the driver for plant and fruit growth.

"Without sunlight the correct hormones are not created and thus blossom buds are not created. Hence why pruning is in part about maximising sunlight striking all parts of the tree thus having fruit produced over as much of the tree as possible.

"If there is less sunlight there is going to be less sugars to pump into the fruit or less oil for nuts. So, fruit are either going to be smaller or less of them."

That is why many members crop volumes/production have struggled in the areas of the very wet summer, as sunlight hours are down on a typical day causing flow-on effects, says Whyte.

"The good news is that the weather is variable and although every year seems to give its challenges, growers know that good follows bad and next year's challenges will be different."

MetService says in July, only three days had eight or more hours of sunshine.

"And three days had less than one hour of sunshine for the whole day," says MetService meteorologist Thapi Makgabutlane.

She says the total sunshine hours at a station in Auckland for July was 137 hours - about five and a half days - a little higher than the region's July climatological average of 128 sunshine hours for this time of the year.

"So not too bad, but this is not typically a very sunny time of year - second only to the month of June in terms of the least amount of sunshine."

The longest stretch of consecutive rainy days recorded last month was 10 days between 7 and 16 July, she said.

"Although it must be said that some of rain was likely due to a passing shower as the amounts were very small."

Greens in good supply

The lack of sunshine might also weigh heavily on consumers' pockets.

Foodstuffs North Island head of produce Brigit Corson says with tight supply, supermarkets would need imports to meet demand.

"Once-a-year crop products are the expensive ones at the moment.

"Like kumara, that really got hammered earlier on [with the floods and Cyclone Gabrielle] and obviously they are not going to come back and be harvested again until January and February next year.

"Other high-priced items at the moment are things like tomatoes. We are going to need to supplement our supply for customers with some imported products for the next few weeks."

She says consumers should be alert for supermarket deals.

"Greens have been in good consistent supply, particularly broccoli.

"Key things are to always buy in season and look for those big bins at the front of your produce department, they are the overflow with that in-season produce, so they are great deals."

-Rayssa Almeida/RNZ.