At a recent open day in the garden of Gary Smith, Doubtful Creek via Kyogle, proponents of this particular produce compared notes in a bid to co-cooperatively advance the cause.
British transplant Chris Pike, Collins Creek, said the job of feeding his burgeoning pumpkin vine was not a weekly job but a daily one, first creating that all-important bed of mulch then making sure each leaf node was covered to encourage root growth.
“For me the fun of this is seeing the absolute vigour,” he said. “Every day you watch the free space in your garden getting smaller. It’s almost a spectator sport.”
Dairyfarmer John Leadbeatter, Rukenvale, is no stranger to the ‘sport’ having won the innaugural sub-tropical Summerland Giant Vegetable growers’ Association competition four years ago. He has the advantage of being able to source an enormous volume of manure to fertilise his crop, and says round bale lucerne and sorghum silage underneath cow manure makes the best bed as the system retains good moisture.
“But these pumpkins need shade,” he says. In addition he applies liquid fertiliser at night and irrigates prior to dairying, before the sun comes up, to reduce the chance of powdery mildew.
However this season has been difficult, with not enough rain for adequate growth and the showers that did arrive prior to Christmas affected these growers’ ability to correctly apply fungicide.
Mr Smith, who last year weighed in at 604kg but expects this year’s fruit to fall behind by a third, was more descriptive of his season this far. “It’s been a shit of a year,” he said. “We’ve had wind and storms and broken leaves. It seemed to rain in the morning and the night and I wasn’t game to spray for powdery mildew in the middle of the day.”
Added to the misery has been the heat, with pumpkins failing to set female flowers when the temperature climbed above 30 degrees.
Growers on the day put their heads together in a bid to work out how best to cultivate giant Atlantic variety pumpkins in the hot and steamy sub-tropics.
“We’re still trying to work this one out,” said Mr Smith. “We’re trying to get the timing down pat for our climate. You need good soil, good seed and good luck but there’s even more to it than that.”
In Nova Scotia, where the sport was developed, seedlings are grown indoors during the chilly spring but flourish as the days become longer, with early summer rains creating serious biomass. Come the end of the growing season a typical ‘Indian summer’ provides the perfect dry finish.
Sub tropical summers are hot and steamy, with no dry finish at all. Growers here are wondering if they should plant before early September to maximise growing time before the onset of the late summer monsoon.
Dale Oliver, Knockrow via Bangalow, is well experienced in growing giants, setting an Australian record in 2015 with an Atlantic variety weighing 743kg. His patch, in a back corner of his commercial nursery, is covered with hail netting while the naturally-occurring basalt soil is well aerated with woodchip, chicken manure and even coal clinker. But he rues the fact that his growing season is too short.
“A recent giant pumpkin from Rhode Island that weighed 1043kg grew for 100 days. Down in Victoria they can grow for 115 days. Here we are flat out getting 66 days,” he said.
Southern exposure
Growers in the southern states are well positioned to take the crown away from the sub-tropics mostly because of those longer summer days, says Mr Oliver. An extended growing season with critically more daylight hours along with a dry finish to late summer all conspire to help produce a record-breaker in the giant pumpkin stakes.
Dairy farmer Phillip McCauley, Packenham, uses one of his empty calf paddocks to grow giant pumpkins, sprinkling millet and sorghum hay on already nutritious ground to maintain soil moisture – something that is critical in that part of Victoria where the annual rainfall is around 800mm. While there is no such thing as powdery mildew, excessive heat above 40 degrees puts a halt to pumpkin development.
Champion Tasmanian grower Shane Newitt is blessed with even longer summer days and a beaut dry finish but located east of Hobart he rues the bitter south-west wind. As a result he grows seedlings under shelter.
He prepares his soil in accordance with best practice modern agronomy, growing up to three cover crops of oats, lupins, mustard and peas.
He also adds beneficial microbes to his soil: Streptomyces lydicus, Trichoderma virens G41, Azos and Endo mycorrhizal fungi.
As high summer approaches the shade structure is opened up to access long hours of daylight while he monitors plant nutrition via tissue culture. Mr Newitt reckons he is on the cusp of a new Australian record and current champion Mr Oliver agrees. However Tasmanian weather can be cruel at times. Last year’s champion fruit weighed 585kgs at a very young age and was projected to finish around 850kgs until it aborted after days of temperatures in the high 30s. Heat radiating off the steel shade house structure didn’t help.
“There are some mad breeders out there who are striving to reach 1500kg and they will probably get there using artificial support,” says North Coast nurseryman Dale Oliver. “But for paddock pumpkins new records will be limited to climates.”
Girth quest moves south
In the quest for giant pumpkins the Atlantic variety will dominate for some time and those that can grow one in a climate similar to that of eastern Canada and the north-east US will hold an advantage.
For that reason the best Australian pumpkin growers believe southern latitudes in this country will produce future winners, not necessarily the hot and steamy sub-tropics where previous champions have been harvested.
“I believe the new Australian record pumpkin will one day be grown around Bega,” says top Tasmanian grower Shane Newitt, who reckons the South Coast climate is about perfect for Atlantic variety pumpkins.
The current generation of giant pumpkin genetics relies on the latest and greatest seeds taken from the Atlantic variety because that’s where the work’s been done. So don’t expect a world record Queensland Blue for a while, and as far as a giant Jap – well – that pumpkin belongs to Cucurbita moschata, not Cucurbita maxima.
Interestingly, moschata handles heat and humidity better than maxima and one day might produce a bigger pumpkin Down Under but the humongous maxima varieties – particularly those descendants of 1068 Wallace, a half-tonner grown in Rhode Island in 2003, have set a new pace in the global quest for girth.
North Coast nurseryman Dale Oliver, Knockrow, who in 2014 grew the fifth largest squash in the world, weighing 612kg and who currently holds the Australian record for a giant pumpkin at 743kg, says seeds from that Wallace pumpkin have produced consistently large offspring, with descendants breaking the magical 1100kg mark in Switzerland under laboratory conditions. Single seed from a previous Swiss winner sold in the UK last October for more than $2000.
But seeds are largely traded for free, with avid growers are all too keen to share their hard-won information. Sub-tropical giant pumpkin growers on the Northern Rivers have been astounded by the generosity of Northern Hemisphere participants who until the onset of cucumber green mottle mosaic virus sent giant genetics via seed through the post with the only thing demanded in return being a photograph of its progeny.
Future relies on Atlantic genetics
RECENT quarantine measures in the Northern Territory surrounding cucumber green mottle mosaic virus almost cruelled the importation of giant Atlantic pumpkin seeds from the northern hemisphere.
However growers in Australia are confident that a new testing regime in the US will supply those Downunder with safe stock.
As an example of how the ‘sport’ looks after itself, laboratory testing of seed and paperwork is currently being done by volunteers who don’t charge for their efforts.
Victorian dairy farmer Phillip McCauley, who has won heaviest pumpkin at the Packenham Show for 14 of the last 15 years (cows trampled his patch one season), says he and other local growers sent money to the US for testing, but they were never asked to pay. The first lot of safe seed is currently in quarantine and is expected to be released later this month.
More vegetables
Pumpkins are not the only fare being grown with size in mind. Victoria’s Mr McCauley also has a flair for giant cabbages, carrots, radishes, beans and beetroot.
On the North Coast, Rukenvale dairyfarmer John Leadbeatter had a go at big beetroot and Swedes this year and has produced giant tomatoes in the past.
Fellow coaster Stephen Kelly, Yamba but formerly of Gunnedah, excels at giant tomato production producing one specimen weighing in at 1.28kg. He sourced his seed from an old Italian gardener after literally stealing the man’s lunch during smoko.
“He wouldn’t give me even one seed of that tomato which had a slice in his sandwich bigger than the bread,” Mr Kelly recalled.