A crimp roller is assisting Australia's only pumpkin seed farmer control weeds, save water and improve soil health.

The luscious green hue of the oil produced from Pepo Farms' pumpkin seeds mimics the vibrant green of the cover crop that kick starts its life cycle.

Prized for its health benefits and gourmet applications, the oil is common in Slovenia where the ancestors of Sharan Rivett, Australia's only pumpkin seed farmer, first learned to grow, harvest and press pumpkin seeds. Sharan's intergenerational knowledge and her can-do attitude have brought Styrian pumpkin seeds to Ovens, near Bright, in north-east Victoria.

It's half a world away from the rich soils and year-round cool climates of Slovenia, but Sharan has innovated new growing methods and repurposed equipment to grow the pumpkins regeneratively and at scale.

Snapshot

Farm/Enterprise Name: Pepo Farms

Farm/Enterprise Location: Ovens, Victoria, Australia

Type of Enterprise: Horticulture

Primary Markets Served: The pumpkin seeds are sold through the Australian Pumpkin Seed Company online and via its store at Ovens. They are also sold through 600 health food stores across Australia.

Staffing: 12 full time, 8-10 during planting

Property Size: 50ha

Property Elevation: 223m

Average Annual Rainfall: 1,108mm

Climate: Alpine valleys

Soil Types: Heavier sandy clay or loam

Website: www.pepofarms.com.au

Challenge

In an effort to farm in climatic conditions closer to those in Slovenia, 13 years ago Sharan moved the business from Queensland, where she and her family had started it, to north-east Victoria. She had to work out how to grow the plants in improved, but new, climatic conditions, with no industry support.

Sharan's come a long way, creating a growing industry and a value-add business while also supporting other farmers on their food production journey. However, there's always room for innovation and improvement, and she is working on how to control weeds, retain moisture and improve soil health in her farming operation.

Weed control

Weed control is a major issue for Pepo Farms. They don't use chemicals, and regular tilling of the ground can be time consuming, expensive and bad for soil health. Grasses are the most common problem for the operation, with weeds sapping the soil of water and nutrients.

Water retention

Pepo Farms relies on overhead irrigation to get the pumpkin plants to produce in what can be scorching Australian summer heat, even in the climate of the Alpine Valley. The farm is looking at converting its overhead watering system to drip tape to reduce water consumption and evaporation. 'The tape can go on top of the soil or we can bury it,' Sharan says, further explaining that irrigation is mostly required later in the growing season when there is lots of leaf cover and the roots are down deep.

Soil health

What you take from the soil you've got to give back.

Soil health is very important to Sharan. She adds worm juice from NutriSoil, guano and a winter cover crop, but is always looking for new ways to increase organic matter and biology to the soil. 'Throughout the season we're checking on fertiliser rates with petiole tests to monitor what the plant is actively using,' she says. Pumpkins are traditionally grown in a rich organic soil, so optimised soil health is also required for healthy productive plants. 'What you take from the soil you've got to give back,' she says.

Solution: Crimp rolling a cover crop

Weed control

Pepo Farms has been trialling a crimp roller to assist in the control of weeds, increase water retention and enhance soil health.

The crimp roller in action in spring ahead of planting.

Sharan describes the crimp roller as a big round tube that is drawn behind the tractor. It has fins on it that press into the ground. Vegetation is not only flattened, but the stems are crushed at 10cm intervals as well, which helps to terminate the plant. As the stems are still attached, not slashed off or mulched, they stay in place and form a dense mat which prohibits weeds. It also adds dry organic matter which breaks down more slowly.

Pepo Farms initially trialled sowing 100kg/ha of a predominantly rye corn cover crop, with 20kg/ha of vetch; however, they've had better results with the latest planting of 150-200kg/ha of rye corn and vetch. Rye corn was selected due to its height and bulk. Vetch, a legume, is included to add nitrogen to the soil.

After some trial and error, Sharan has found that the fallen cover crop must be 5cm to 10cm thick, after it's been crimped, to provide that bulk coverage necessary to be beneficial throughout the pumpkin-growing season. The cover crop is planted at the end of the pumpkin harvest in April or May and then crimped at the end of October or early November ahead of planting. The cover crop can reshoot, but the winter active plants come to their natural end of life as the soil temperature warms. The pumpkins then take over as the weed matting starts to break down.

Water retention

The cover crop not only stops weed growth, it keeps moisture in and the soil cooler.

After the cover crop is crimped the roots stay in place, and the stems form a dense mat which prohibits weed and improves soil health and water retention.

Tilling the soil for weed control is no longer necessary, which opens up the opportunity to upgrade the irrigation system from overhead to underground irrigation, which would deliver significant water savings. There could also be significant plant health benefits, such as prevention of powdery mildew.

Soil health

The cover crop matting lasts the season and is mulched into the soil when the mature pumpkins are pushed into rows for harvest with specialised machinery.

Essentially it becomes dried-off brown matter that has slowly been breaking down. This brown organic matter contributes to soil health in combination with the green organic matter from the vines at harvest.

Sharan says this cycle starts to improve soil and that getting organic matter into soil builds up microbes and bacteria to help feed the soil.

Outcome

Trial and error

'We trial in smaller areas, then it's not so bad on the budget if it doesn't work out.'

Sharan admits she hasn't arrived at perfect solutions yet and is on a continual learning and improvement journey. This is the case with the crimp roller and other changes that are being trialled on the farm. She has found that when changing practices it's best to trial them in smaller areas before taking it to a large scale. 'We trial in smaller areas, then it's not so bad on the budget if it doesn't work out,' she says.

Flow on effects

Changing one practice can have a flow-on effect to other parts of the farm. For example, the thick matting may prevent weeds but it necessitates a change in how seedlings are sown. The current machine drags a groove in the soil, which the seedling is dropped into, and then closes the soil over it. This can't be done with the thick weed matting as it tangles in the machinery.

Pepo Farms is currently trialling a water wheel, which presses seedlings into the holes created by spikes that are the same size as the seedling plug. The new system doesn't require any scraping, just plugging them straight into the ground.

It's the latest iteration in the change of how pumpkin seeds have been sown in Australia's diverse soil types and climates. In Queensland, seeds were directly sown into the ground, but a different fungal and bacterial load in Victorian soil led to learning to grow and transplant seedlings instead.

A thirst for knowledge and improvement

The 2023 harvest at Pepo Farms was a record yield of pumpkin seeds. It was a tough start, however, with sowing delayed by three weeks due to floods. After the rains, it turned into a bumper growing season, with lots of warm, clear skies for the sun-loving pumpkins.

It's not just weather that controls the outcome of the season, although it's obviously important. It's Sharan's expert management decisions, cultivated by years of practical experience, and her willingness to try new things, that are yielding great results.

This thirst for knowledge and improvement is surely watering the seeds of success for Pepo Farms and the Australian Pumpkin Seed Company.

Fun fact

Sharan's drive toward best practice doesn't end at soil heath; it extends throughout every part of the enterprise. Pepo Farms uses a purpose-built flat bed dryer, which generates warm air through burning waste oil, to dry its pumpkin seeds. The seeds were previously dried in the sun, but the updated method dries more consistently and caters for the larger scale operation. Using waste oil to power the drier is also a big tick for Pepo Farms.

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