Growing celery in Western Australia

Introduction

Celery (Apium graveolens) belongs to the Apiaceae family and is related to parsnips and carrots.

WA is practically self-sufficient in celery, with small quantities brought from interstate in summer. Most comes from outer metropolitan locations on the Swan Coastal Plain as far south as Bunbury, with some from the lower South West and South Coast. September to January plantings give the best results in southern districts.

Celery is grown from transplants that are almost exclusively grown by specialist seedling nurseries. They can provide advice on current varieties.

Under cultivation, celery is grown as an annual and is harvested before the plants ‘bolt’ into flowers and stalks become pithy and soft. Under cold conditions (4 to 13°C for more than 10 days in the seedling stage), May to July plantings in the Perth area may bolt in spring. These crops will not be suitable for marketing unless harvested early at a smaller bunch size.

Soils must be well drained with high levels of organic matter, which may be supplied from the residues of past crops or compost. Slightly acidic soil is optimum for celery (pH_Ca range 5.0 to 6.0). Apply lime to the soil if the pH_Ca drops below 4.8.

Planting, seed and seedlings

Celery is planted all year on the coastal plain but best yields and quality are obtained from late February to August plantings.

It contains a glycoside which can give a bitter taste at some times of the year, especially in spring.

Celery is not sown directly in the field and seedlings in cell-packs have replaced the traditional method of using open seedbeds. Most growers purchase plants from nurseries, but some produce their own cell-pack seedlings.

If using seed, treat seed less than three years old with hot water at 50°C for 30 minutes the day before sowing to control Septoria leaf spot disease. Dry rapidly after treatment and dust the dry seed with a fungicide registered for this use before planting.

Seedlings should be ready for planting four to five weeks after pricking out. The best size for planting is at the four-leaf stage.

Planting and rotations

Celery seedlings are normally planted by machine. Hand planting usually gives more uniform establishment but is more expensive.

The crop is typically grown in three or four row beds with 1.5–1.65m between tractor wheeltrack centres. Aim for a spacing of around 40cm between rows and 40–45cm between plants within the row. Wider spacings are preferable for winter plantings to minimise fungal disease.

It is possible to grow one crop of celery on the same ground each year if it is rotated with other crops for the rest of the year. Adopt a longer rotation if yields are declining.

Fertilisers and irrigation

Fertilisers

Apply the following rates of magnesium and trace elements to the soil every 18 months:

50kg/ha           Magnesium sulphate to supply magnesium

20kg/ha           Manganese sulphate to supply manganese

18kg/ha           Borax to supply boron

18kg/ha           Iron sulphate to supply iron

18kg/ha           Copper sulphate to supply copper

18kg/ha           Zinc sulphate to supply zinc

2kg/ha             Sodium molybdate to supply molybdenum.

If necessary, apply 50 cubic metres of compost per hectare one to four days before transplanting. This adds organic matter, supplies nutrients for the first three weeks and helps retain moisture in the soil. Bulky residues from preceding crops in the rotation have the same effect and celery crops following others such as cauliflower and broccoli may not need compost.

Celery is a shallow-rooted crop with high fertiliser requirement. A comprehensive fertiliser program for year-round production on sandy soils called ‘The 3Phase method for growing celery’ is available.

Table 1 shows the rates of fertiliser required to supply certain nutrients and their effect on celery.

Irrigation

Celery is a shallow-rooted crop requiring a lot of moisture. Comprehensive information on the principles of irrigating vegetable crops in WA can be found  on the vegetablesWA website. Irrigation rates for your specific location and circumstances can be estimated using the Irrigation calculator.

In warmer months, apply three-fifths of the water early to mid-morning and two-fifths early to mid-afternoon. In cooler months, apply all of the water early to mid-morning.

Water used for irrigation should contain less than 1000mg/kg of total dissolved salts, or have an electrical conductivity (EC) reading of less than 180mS/m.

Physiological disorders

Bolting

Bolting or premature flowering is induced in young plants by cold weather followed by warmer conditions in spring. Its impact may be reduced by growing varieties which have some bolting tolerance or by raising seedlings in a heated greenhouse and harvesting early before the seedstem has had time to develop.

Black heart

Black heart appears as a blackening of the tips and edges of young leaves in the centre of the plant, especially in hot, cloudy, humid weather. Calcium nitrate sprayed at high water volume to ensure penetration to the growing points of plants may help to minimise the severity of black heart (see Table 1).

Pests, diseases and weeds

Pests

If root knot nematodes have caused problems with previous crops, do not plant celery in that area.

Lucerne leaf roller caterpillar may be a severe problem in summer and autumn and is difficult to control. Pesticide sprays may be necessary every four to seven days in severe outbreaks.

Other pests that may require control are aphids, caterpillars, cutworms, two-spotted mites, thrips, leaf-hoppers, snails and Rutherglen bugs.

Diseases

The major disease of celery is late blight, Septoria apicola, seen first as small circular spots on the tops of older leaves. Eventually the whole leaf dies. It is worse in cool, moist weather.

Bacterial soft rot may cause severe problems, especially in hot, humid conditions and following excessive applications of nitrogen. Rotting occurs mainly on the stems in the field, in storage or in transit. Infected plants that escape detection during harvest may spread the infection in the packing shed.

Sclerotinia or white mould may occur in cool to warm, moist conditions as a white growth on the stems in the field or in storage.

Other diseases are early blight, Cercospora apii, and grey mould, Botrytis. Celery mosaic virus occurs in WA and severity varies from season to season, but is rarely serious.

Weeds

Weeds can be difficult to control  because celery is a long growing crop that takes considerable time to fully cover the ground. During the early period, weeds compete strongly with the crop, but not after full ground cover is reached.

The registration and availability of chemicals for pest, disease and weed control changes regularly. Consult a trained and experienced horticultural agronomist or the Australian Pesticides and Veterinary Medicines Authority (APVMA) website for chemicals which are currently registered or have a permit for use on this crop.

The information on the label or permit for a chemical must be followed including the directions for use, critical use comments, withholding period and maximum residue limit. Quality assurance (QA) schemes for horticultural crop production require producers to have current information on chemical registrations and permits readily available.

Harvest and yield

The time from transplanting to harvest varies from 12 weeks in summer to 18 weeks in winter. The best harvest time is the early morning.

Reasonably compact plants over 1kg in total bunch weight are preferred, with 1.5 to 2kg bunch weight more common. Harvest before the stems become pithy or hard and fibrous. In spring, pick at earlier maturity to reduce bolting.

Harvesting celery is strenuous and it is best to wear rubber gloves. Some people develop skin allergies when handling celery or allergic reactions after eating it.

Pack and grade bunches in the field in 84L crates (30kg net). In the field or packing shed, wash with clean, cool water to remove soil. Perforated polythene sleeves can be placed over the stems, with the top left open, after free water has drained from the leaves and stalks. Bunches can be dipped in cold water at 0°C (hydro-cooling) to remove field heat before sleeving.

If hydro-cooling is not done, cool to 0°C with forced air or vacuum cooling in crates or bins as soon as possible after packing. Celery can be maintained in good condition for four to five weeks at 0°C and a high relative humidity (90-95%).

Celery is the highest yielding vegetable crop in Western Australia and produces 90 tonnes or 3000 crates per hectare under good management.

Acknowledgement

The original content of this page was authored by John Burt.