Growing garlic in the Moreton region
Alan Duff, Department of Primary Industries and Fisheries, Queensland.
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Soils
Soils preferred are sandy to clay loams, rich in organic matter and reasonably well drained. As with onions, there are problems with a soil pH of over 8.0.
Varieties
Glenlarge and Southern Glen are superior large-cloved varieties developed at Gatton Research Station, they are the highest yielding and have a light purpling of the outer skin. Southern Glen matures approximately 1 to 2 weeks before Glenlarge. The old medium and small purple varieties (probably of Taiwanese origin) are now rarely grown commercially because of their small clove size. Apart from South African White, which tends to produce a high percentage of small cloves, most other imported and southern strains have failed to produce bulbs. Giant Russian garlic, which is really a member of the leek family, is grown but the market potential appears to be limited.
Planting
Planting times
Plant from mid-March to early April. Later plantings result in a reduction in bulb size. Garlic requires a cool growing season.
Planting material
Garlic is vegetatively propagated using cloves, which are small bulbs or sections broken out of a complete garlic bulb. These are obtainable from growers. Larger bulbs and larger cloves provide the best planting material. Do not plant bulbs from soils infected with the disease white rot. The amount of planting material required is 400 to 600 kg/ha.
Planting method
Plant in rows 45 to 60 cm apart with 8 to 13 cm between plants and no deeper than 5 cm. The broken cloves are planted by manually dropping them through a tube behind a cultivator, or by specially developed planting machines. The recommended plant density is 25 to 30 plants per square metre.
Nutrition and irrigation
Nutrition in fertile soils
Usually only nitrogen is required at 30 to 120 kg/ha; alternatively an NPK mixture, such as 17:3:6, plus an early nitrogen side-dressing may be applied.
Nutrition in less fertile soils
Use an NPK mixture, either 17:3:6 or 15:4:11 at 300 to 450 kg/ha plus nitrogen side-dressings as required. The fertiliser is spun on in several applications before bulbing. Poorer, sandy soils will require mixtures containing higher phosphorous. Avoid late applications of nitrogen because they will cause quality problems.
Irrigation
In the early stages, frequent light irrigations of about 15 to 20 mm are needed. Less frequent and heavier irrigations can be applied for later growth - approximately 50 mm per fortnight. Avoid stressing the crop, particularly during bulb development.
Pests and diseases
Weeds
Weed control is mainly by hand-chipping and inter-row cultivation. There are some herbicides currently registered, or with permits for use on garlic.
Insects
Onion thrips are the only major insect pest of garlic, if found spray with a registered insecticide.
Diseases
Leaf diseases of garlic include downy mildew, purple blotch and rust. For management of the soil-borne disease pink rot, avoid rotations with cereal crops. Use disease-free planting material to prevent the spread of white rot.
Harvesting and marketing
Maturity and harvesting
Maturity in garlic is not as easily defined as it is in onions where the tops go down. Some indicators of maturity in garlic include progressive yellowing of the leaves, death of the youngest leaves and the tops can be easily bent over.
Garlic is usually harvested (pulled up) by hand about 5 to 6 months after planting, tops and roots are removed by dagging shears after a short drying period in the paddock, or for longer periods in sheds. Around a 5 to 10 fold return on planting material weight can be expected under good crop management conditions. Yields range from 4 to 8 t/ha.
Marketing
Garlic is sold in standard onion bags or small pre-packed quantities in mesh bags. More innovative packaging may improve the return to the grower.
DPI&F information and services
- To access DPI&F's information and services, Queensland residents can contact the DPI&F Customer Service Centre on 13 25 23 for the cost of a local call, from 8 am to 6 pm Monday to Friday (excluding public holidays). E-mail callweb@dpi.qld.gov.au. Non-Queensland residents phone (07) 3404 6999.
- Current national information on agricultural chemicals registered for use on all crops is available on the Infopest CD-ROM. Write to DPI&F, GPO Box 46, Brisbane, Qld 4001, E-mail infopest@dpi.qld.gov.au, visit the Infopest web page, or phone (07) 3239 3967 for further information.
- This Note is also published on the DPI&F's PrimeNotes CD-ROM.
- Other horticultural information is available on the Plant industries home page.
Industry links
- Industry links is a page of links to various sites of interest to horticultural growers.
Information contained in this publication is provided as general advice only. For application to specific circumstances, professional advice should be sought. The Department of Primary Industries and Fisheries Queensland has taken all reasonable steps to ensure the information in this publication is accurate at the time of publication. Readers should ensure that they make appropriate inquiries to determine whether new information is available on the particular subject matter.
Last reviewed 22 October 2007