AHEIA - Providing leadership to support and strengthen Australia's trade in horticultural produce.

Lettuce

History

Originally viewed as a weed, it was only used for its oil rich seeds until the ancient Egyptians later cultivated it for its leaves. The explorer Christopher Columbus introduced lettuce to the Americas in the 15th century and by the late 20th century, the world was consuming lettuce. Lettuce seeds arrived in Australia on the First Fleet and now days, this popular vegetable is often found in backyard gardens around the country.

What are they

Lettuce is a part of the daisy family and is grown as a leafy green vegetable. Lettuce varieties range in sizes, shapes, colours and flavours however crisphead (iceberg), romaine (cos), butterhead and looseleaf are the most popular in Australia.

  • Crisphead has a compact, round head and firmly packed leaves
  • Cos has long, dark green leaves
  • Butterhead has soft green or brown-red leaves
  • looseleaf varieties do not form heads and come in various shapes and colours

How are they grown

Lettuce grows best at relatively cool temperatures and does not like extreme heat or cold. High daytime temperatures greater than 30°C at or near harvest can cause wilting. Lettuce can be grown from seeds or seedlings and requires plenty of water as it has shallow roots.

Where are they grown

Lettuce is grown all over Australia however the main lettuce production regions in Australia are the Lockyer Valley and Eastern Darling Downs (SE Qld); Hay and Central West (NSW); Lindenow and Robinvale (Vic); Manjimup and Gingin (WA); Virginia (SA) and Cambridge, Richmond and Devonport (Tas).

How to know when they are ripe

Lettuce plants are usually ready to harvest in six to 12 weeks. Around a week before your estimated harvest date, pick a few lettuces that appear to be ready to harvest. Push on the top of them to see how firm they are.  If the larger lettuces are firm, cut a few in half and check how closely leaves are packed in the head. If they are packed closely and most of the field has heads of about that size and firmness, the crop is ready to harvest.

Knowing when they are ready for harvest differs between varieties.  This depends on variety, season and the weather conditions

Seasonality

 

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Lettuce

 

 

 

 

 

 

 

 

 

 

 

 

 

Weather impacts

Heavy winter frosts of -3C will damage lettuce and kill young seedlings. During extensive rainy weather the plants are likely to become infected with diseases.

Local market

Fresh consumption including pre packaged salads.

Storage

Lettuce should be pre-cooled to as close to 1°C as possible within 1 to 2 hours of harvest. After pre-cooling they should be stored at 4°C and 95 to 100% relative humidity.

Nutrition

Depending on the variety, lettuce typically has a good source of Vitamin A, C and K, Iron and folate.

Packaging

Solid lettuce heads are cut, trimmed to 4 to 5 wrapped leaves and packed into waxed cartons, 12 to 16 heads per carton. Lettuce heads should be tightly packed in the carton to avoid movement during transport. Pack in two layers with hearts to the bottom and top, and butts to the middle.

 

 

References

Agriculture Queensland ‘Critical Temperature Thresholds Lettuce’ By Peter Deuter, Neil White, David Putland  http://www.managingclimate.gov.au/wp-content/uploads/2012/02/Critical-temperature-thresholds_Lettuce_V2.pdf (Febrary 2016)  
Queensland Department Agriculture and Fisheries http://era.daf.qld.gov.au/1660/4/3growlet.pdf (January 2016)

Pumpkin

History

Pumpkins have been cultivated for more than 5000 years. They are believed to have originated in Central America. Pumpkin seeds were carried by explorers and nomadic tribes and eventually spread to Asia and Europe.

What are they

Pumpkins are members of the Cucurbitaceae family which also includes cucumbers, gourds, melons, squash and zucchinis. Pumpkins can vary in colour from white to yellow to orange to green.

How are they grown

Pumpkins are frost sensitive and need frost-free growing periods of 4 to 5 months. High temperatures (above 35C) and low humidity are not conducive to high yields. Temperatures of 20C to 35C are ideal for maximum production.

The seeds develop into a vine with tendrils that grow along the ground and wrap around all obstacles that they encounter. Male and female flowers are produced on a single plant, with bees and other insects transferring pollen between flowers.

Where are they grown

All over Australia

Variety

Butternut, Windsor Black, Queensland Blue, Jarrahdale, Sweet Grey

How to know when they are ripe

It takes about 24 weeks before the pumpkin plant is mature and the pumpkins are ready for harvest. A cracked, dried stalk indicates that the pumpkins are ready for picking. Depending on the variety, the skin (rind) also changes colour as the pumpkin matures.

Seasonality

 

Jan

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Dec

Pumpkin

 

 

 

 

 

 

 

 

 

 

 

 

Local market

Fresh consumption and processed

Storage

Pumpkins for storage must be sound and should be handled with great care. Any bruise will soon develop a rot, which can spread through the stack. The ideal storage is a rat proof shed, built well off the ground, preferably at the level of a motor truck tray. Provide plenty of shelves to allow free circulation of air inside the shed.

In areas not subject to severe frost, pumpkins can be stored satisfactorily under heavily-foliaged cypress hedges, but for long storage pumpkins must be stored at temperatures above 7°C or breakdown caused by cold damage will occur.

Nutrition

  • Pumpkin is an excellent source of beta-carotene, which gets converted to vitamin A in the body, and vitamin C.
  • It also contains dietary fibre and minerals such as potassium (which helps to regulate blood pressure) and manganese (involved in the regulation of brain and nerve function).

Packaging

Most growers sell their pumpkins in bulk, by the kilogram. Butternut pumpkins are usually sold in 20 kg red net bags or fibreboard cartons

Other uses

Both the seeds (roasted) and flowers are edible.

References

Better Health Victoria https://www.betterhealth.vic.gov.au/health/ingredientsprofiles/Pumpkin (January 2016)  

Queensland Department of Primary Industries http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0004/311485/Pumpkin-production.pdf (January 2016)