Posts Tagged ‘ shade cloth ’

Issue 107: Territory Lettuce

July/August 2009
Story and pictures by ADAM REYNOLDS

The climate in Central Australia is vastly different from the more temperate coastal regions of Australia. Extreme temperatures, lower humidity, seasonal high winds, and occasional dust and hail storms, bring with them many growing challenges.

Located 1,500 kilometres from Darwin and 450 kilometres from Uluru (Ayers Rock), Territory Lettuce is a postage stamp-size green oasis in the middle of a vast red desert. I first met the principal, Moe McCosker, at the last AHGA conference held in Launceston, Tasmania, and jumped at the opportunity to visit his hydroponics operation during a recent tour of the Territory. In its eighth year of drought, the Territory has had its average annual rainfall, but it’s been at the wrong time of year with no decent follow-up rain. During my visit the landscape was punctuated by spectacular gum trees, refreshing waterholes and awesome colours, accentuating the incredible beauty of this ancient land.

A plumber by trade, Moe’s introduction to hydroponics began when he grew flowers for his wife’s florist shop in Alice Springs. That was 17 years ago. Today, he has expanded his business to include an open-air hydroponic lettuce and herb operation a few minutes’ drive from Alice, and growing cabbage and cauliflower in soil at nearby Rocky Hill with Ritchie Hayes. Moe’s work day starts at daylight, before the heat makes picking and planting uncomfortable.

Shirley Reynolds marvels at the size of the cabbage.

Growing challenges
With daytime temperatures in the low to mid 40s in summer and overnight temperatures down to -4˚C in winter, the growing climate in Central Australia is vastly different from the more temperate coastal regions of Australia. Combined with lower humidity, seasonal high winds, and occasional dust and hail storms, growing in the Red Centre brings with it many challenges.

The 3ha crop is covered with hail protection netting.

“Growing in this climate comes with experience,” said Moe.

“We’ve got a lot quicker turnaround for lettuce than what they get down south. In winter we’re cranking 4 weeks, maybe stretched to 5 weeks. Down south it’s 8-10 weeks,” explains Moe.

Moe’s experience came at a high cost. Extreme temperatures during summer and winter, occasional pest infestations and frequent power failures resulted in crop losses in the early days. While being a plumber has its advantages, he drew on the experience of consultant Gary Calabria, a relationship he still maintains, to overcome the many challenges to grow lettuce and herbs in the desert. Although the consultant travels from the east coast of Australia to the Red Centre regularly, they frequently talk on the phone and share ideas.

“In the beginning there was a lot of trial and error with crops wiped out at times from one thing or another. It was heartbreaking,” laments Moe.

Moe McCosker gained his experience from trial and error.

“September and October are our windiest months and we use windbreaks made from shade cloth,” continues Moe.

Wind and dust protection measures include shade cloth barriers.

Eucalypts and peppercorn trees (Schinus molle), an introduced species noted for its ability to cope with hot dry conditions, border the property and help shelter the crop from strong winds.

“We don’t have too much trouble with the dirt and dust, but in dust storms there’s not much we can do.”

According to Moe, when the temperature gets below zero in winter the plants freeze, but they recover if the nutrient solution is recirculating.

“The sheer volume of water going backwards and forwards acts like a radiator. Once the water temperature gets too low plants go into dormancy,” he explains.

At the other end of the scale, when the temperature gets to 38˚C in summer, the cooling towers switch on. A pioneer in cooling tower technology (Moe has been using them for 14 years), these heat removal devices cool water to below ambient dry-bulb air temperature. In simple terms, a fan sucks the solution upwards before the water drops down through a series of waffle pads, thus increasing the surface area and cooling the water. In summer, Moe runs the towers 24/7.

“We can have a 40˚C day and I can keep my water temperature under 30˚C,” he said.

“The hotter days also give lettuce a real hurry-up, particularly when we get high humidity. We need to be on the ball picking if they look like they are going to jump (bolt),” he added.

Although hail storms are infrequent, their arrival is unpredictable and usually results in crop damage. To protect the crop Moe covered the growing area with hail netting about 5 years ago, a total area of 1.4ha (3 acres).

Like all horticulture operations, pests are a problem from time to time with thrips and mites the main offenders. When they do come through Moe reads the signs and treats the crop quickly. Yellow sticky traps strategically placed around the crop monitor pest populations. When pesticides are required Moe has learnt the hard way that application rates are different for the Red Centre, where recommended doses become toxic.

To overcome power failures Moe invested in a backup power generator, a significant investment, but a necessary one when the power grid is unreliable.

“In summer we can’t be without power for more than ½ to ¾ hour. Over the years I’ve lost a couple of crops due to power blackouts for 4-5 hours. If we lose a crop then we’re out of business for a month,” he explains.

According to Moe the backup generator has paid for itself three to four times over. If power drops down for more than 10 seconds, the generator automatically kicks in.

The system
The open-air hydroponic operation consists of 200 waist-high NFT tables with a capacity to grow 90,000 lettuce and herb plants, including nursery plants. Because of the hotter temperatures the tables are only 6 metres long, compared to 12-18m in coastal regions. However, the shorter runs mean higher power cost.

Shorter bench runs mean higher power costs.

Lettuce varieties include all the standard types – red and green coral, oak, butter, mignonette, and baby and large Cos. Specialty lines include red and green Salanova® varieties, which are ideal for mesclun mixes. Just one cut and the lettuce leaves separate into numerous small, ready-to-eat leaves. Over recent years mesclun has become popular with restaurants and supermarkets from Darwin to Uluru. Mediterranean herbs and Asian vegetables include parsley, dill, coriander, basil, arugula (roquette) and bok choy.

Mesclun (pronounced mess-klunn) is a popular salad mix in the hospitality industry.

Asian vegetables include this healthy crop of bok choy.

The farm operates four recirculating systems to meet different nutrient regimes, each with its own in-ground nutrient tank and cooling tower. Running four independent systems also means higher power costs. However, running multiple growing systems is also a risk management strategy to minimise crop losses in the event of Pythium. Cleanliness and hygiene are major considerations to prevent this and other waterborne diseases, especially in summer. Between crops the tables are washed and dried before replanting, and tanks are cleaned regularly.

The facility operates four separate growing systems with in-ground tanks and cooling tower.

With unreliable rainfall, the facility uses town water, which is a “bit hard”. The raw water runs through a Reverse osmosis plant to purify the water, and carbon filters are used to help sterilise the water from pathogens.

“It comes out very nice water,” says Moe.

Town water is purified using reverse osmosis equipment.

The water is then treated with ultraviolet radiation, before the addition of fertilisers. Sterilising water with UV causes a reaction with iron, which is taken out of the water column, resulting in a possible iron deficiency in plants. It has been proposed that iron chelators can be useful agents against the damaging effects of both short- and long-term UV exposure.

RO water is treated with UV radiation.

Waste water from the RO plant is used to irrigate 40-50 citrus trees.

The facility includes a small plastic greenhouse for raising seedlings. Seeds are started in a propagation mix of vermiculite and peat moss.

Seeds are planted in trays using a vacuum seeding machine.

The business employs four pickers and a permanent farm manager, a former chef who previously worked in the hospitality industry at Uluru. Pickers are usually backpackers who want to extend their visas.

“This (Alice Springs) is usually the last stop before they (backpackers) realise they want to stay in Australia for another 12 months, and they need to find work to extend their visas,” explains Moe.

During harvest the facility operates two quad bikes with trailers containing large bins. As lettuce is harvested, the bins are taken to the on-site pack house for washing, drying, packing and cooling. For mesclun, the roots are cut away during harvest. In winter, the average daily harvest for mesclun is 60 boxes, or around 180kg. In summer the harvest is 12,000 head of lettuce each week, around 200 cases of cut salad leaf, and a further 100 cases of herbs and Asian vegetables.

The operation includes on-site washing, drying, packing and cooling facilities.

The markets
Territory Lettuce markets its produce to Coles supermarkets and the hospitality industry from Darwin to Uluru. According to Moe the tourism industry in the Territory is still strong with 10 pallets of lettuce (60 boxes to each pallet, 10-12 lettuce per box) delivered to Darwin weekly. Another three pallets go to hospitality outlets at Uluru and Kings Canyon. Territory Lettuce also supply restaurants and hotels in Alice Springs, with excess produce shipped south to Adelaide.

“We’ve got enough stock here for town deliveries and basically pick to order,” said Moe.

Local deliveries are picked to order.

Pallets go from the cool room into Coles trucks twice weekly for delivery to Darwin and Uluru. Once produce leaves the farm, responsibility for HACCP controls rests with the supermarket chain. Moe prefers not to sell his produce to Woolworths because of its central purchasing system, where lettuce and herbs would be shipped to Adelaide and then trucked back to northern markets.

Although Moe gets a premium price for his lettuce, freight costs are high.

“In the Territory it’s more expensive to grow than anywhere else,” explains Moe. “The cost of fertilisers has jumped dramatically in the last 12 months, overall 30-40%, and input costs for freight on fertiliser, cardboard, seed and propagation mix are also higher.”

He added that because of the extreme climate the cost of electricity is significant, and labour represents 30% of overall input costs.

Final remarks
With general turnover for fresh produce in the Territory increasing, Moe has big plans for the business. Despite the higher production costs and challenges of growing in the Red Centre, he hopes to double his business over the next couple of years.

“The demand is there and we want to expand, but it’s a case of sitting down and working out where to put extra benches,” said Moe.

He added that there is little room for expansion on the current site, which is surrounded by Crown Land.

“It’s all Native Title country out here. I can probably put another 40 benches in this year,” he calculates.

In the meantime, he’s hoping some land will become available in the future and plans to build plastic greenhouses to give him the growing edge in winter.

About the author
Adam Reynolds is the co-publisher of
Practical Hydroponics & Greenhouses magazine and co-recipient of Publishers Australia Bell Award for Best Small Publisher in 1998, 2001 and 2002.