A mild winter and an early start to spring have hoed the way for a bumper start to the much-anticipated asparagus season.

The little green spears have hit the supermarket shelves in earnest during the past week, with growers in Waikato and Horowhenua switching to harvesting every day and their Hawke's Bay counterparts close behind.

New Zealanders' asparagus-consumption habits have shifted dramatically over the past 30 years, as Kiwis come out of their cans with a craving for fresh produce, and growers and pickers are working tirelessly to keep up with demand as spring sweeps in.

Geoff Lewis, asparagus industry group chairman and co-owner of Horowhenua asparagus producer and packer Tendertips, said the Waikato region, home to New Zealand's largest asparagus grower, Boyds, had taken the early lead at the start of the season.

Horowhenua and Hawke's Bay were close on its heels and the small South Island growers, which often sold their product directly through farmers markets and roadside stalls, would follow in the next couple of weeks, he said.

All up, 60 Kiwi growers produce up to 3000 tonnes annually across 600 hectares.

The entire crop is spring grown, between early September and New Year, for fresh sale in New Zealand, canning and export, he said.

Like Lewis, Kiwis seem to adore asparagus, even if it does make their pee smell weird.

Of the 3000 tonnes produced in New Zealand, 2500 tonnes is consumed fresh.

Three-hundred tonnes is shipped to Japan and Australia and 200 tonnes is canned.

This was a big change from the 1980s when about half of all New Zealand-grown asparagus was canned, Lewis said.

While demand was steady, price pressure from supermarkets, high establishment costs and difficulties with seasonal labour meant a lot of growers had to pack it in.

It took about six years before growers made up their establishment costs on the perennial vegetable, which was characteristically more like growing fruit, he said.

Unfortunately, all this meant the number of growers had halved over the past few years.

Meanwhile, new developments were being made in the industry.

The purple variety of asparagus, developed by Canterbury plant breeder Peter Falloon, had become increasingly popular thanks to its sweetness and curious colour.

White asparagus, which was popular in Europe, also made the odd appearance at exclusive New Zealand dinner parties.

Lewis said white asparagus was more labour-intensive to produce so it was more expensive and had a more subtle flavour.

While all the green goodness Kiwis are collecting off the supermarket shelves at the moment are New Zealand-grown, during the off-season New Zealand imported asparagus from California and occasionally Fiji, Mexico and Australia.

Bevan Smith, the owner and chef of award-winning Oamaru restaurant Riverstone Kitchen, said that while imports satisfied the hunger for asparagus while the little guys at home were asleep below the surface, fresh was best.

"If you ever see it being sold at a roadside stall, turn around and pull the car over."

ASPARAGUS: THE FACTS

1. New Zealand growers produce up to 3000 tonnes of asparagus a year and Kiwis eat about 2500 tonnes.

2. When the temperature is just right, asparagus spears can grow up to 1 centimetre an hour and are lopped off before they reach 21cm.

3. Pickers at large growers walk up to 180km a day during peak season.

4. At best, asparagus will cost about $5 for 500 grams (two bunches) at the supermarket

5. Asparagus pee is a real thing. Eating asparagus can lead to smelly urine but only those with a specific gene can smell it . . . lucky them. 

- Sunday Star Times