Planting
If using four-row beds, plant strawberries in double rows 30 to 40cm apart. Within rows, the plants should be staggered and be from 25cm to 40cm apart, depending on the vigour of the variety and the mechanical aids used.
About 50 000 to 60 000 runners are required to plant one hectare in the Perth region. In southern regions, where inter-row paths are wider, about 40 000 plants are required.
Plant runners as soon as possible after receival, before roots dry out. If planting is delayed, the runners should be cool-stored at 2°C until needed.
A medium-size paint scraper is used to push the plants down into the bed. The method may seem crude but trials have shown it places the plants at no disadvantage. First pierce a hole in the plastic sheet and holding the plants at a 60 degree angle, rest the end of the roots on the plastic. Place the scraper tip close to the ends of the roots, usually 3 or 4cm from the ends, and push down slowly and firmly until the plant crown is level with the surface of the soil. Withdraw the scraper and firm the soil around the plant.
Where plants are being established with overhead irrigation, make larger planting holes (8 to 10cm diameter) to allow good water penetration.
Pruning and cutting
Runners that develop during cropping should be removed as soon as they appear. Runner removal is generally not considered to be worthwhile late in the season.
If an autumn crop is desired, cut bushes to within 2cm of the crowns between March and May in Perth and between May and July in the south and remove all old leaves. Top removal can be aided by slashers, modified lawn mowers, hedge clippers or sharp knives. New growth will emerge quickly, followed by flowers.
Tops should not be removed in hot weather as the crowns can be damaged. If the weather is warm, irrigate regularly after top removal. To reduce disease build-up, rake up all leaves and burn them.
Growers harvest the autumn crop from early April to June, as the autumn crop may be extended into winter with the use of plastic cloches.
Tunnels
Plastic tunnels (cloches)
Cloches protect the crop from wind, hail and heavy rain during winter and warm the air and soil. They encourage vigorous growth, early fruiting and more even colouring of berries.
Construct cloches by erecting wire hoops about 2m apart across the beds and covering them with a continuous sheet of clear polythene. Attach the polythene so that it can be easily rolled up to allow watering, harvesting and pest control.
Uncover the cloches on hot days to avoid scorching of leaves, and also in warm weather for pollination. The temperature inside the cloche should not exceed 33°C.
High tunnels (Haygrove™)
Some growers are using these for added crop protection and worker comfort. Trials comparing cloches with high tunnels show variable results depending on year and variety. The variety Albion shows more consistent results under high tunnels. Marketable yield will be higher in years with cool rainy weather early in the season.
Given the erratic nature of weather conditions in recent years (for example, summer hail storms), the reduced risk associated with tunnels is worth considering. Since these tunnels do not cover completely to ground level the risks of storm damage to the tunnels are less than with traditional tunnels.
Hydroponic strawberry production
Few growers have adopted hydroponic production to date in Australia. There are high capital costs to establish hydroponic production and prices for strawberries in recent years have been declining due to oversupply.
Weed control
The black plastic mulch controls most of the weeds in the rows. Weeds between the rows are usually controlled with a contact herbicide such as Spray Seed®. Apply this with a hooded sprayer. Do not allow drift to contact strawberry plants.
Alternatively, a ryegrass cover crop can be planted between the rows and that will help stabilise the soil and prevent dust blowing onto the fruit. There are a number of selective herbicides registered for use in strawberries. Consult the APVMA website for the latest information.
Irrigation and fertiliser practice
Information on irrigation and fertiliser programs for strawberries can be found on this website using the links provided.
Harvesting
While strawberries are available throughout the year, supply is heaviest during spring. Crops in the Perth region are heaviest from September to December and southern crops from October to March. Autumn crops may be produced by cutting back plants as described earlier. First year plants yield later than established plants by about a month.
Strawberry beds should be picked over regularly, especially during hot weather when berries mature very quickly. The degree of fruit colour will vary according to the variety, but generally fruit should be picked when half to three-quarters red.
Harvest berries for the fresh fruit market with sepals attached. The stem should be very short or absent. Reject fruit that doesn’t have sepals or is damaged.
Strawberries spoil rapidly, so they must be removed from the field at regular intervals and cooled promptly, preferably using forced air cooling. Fruit should be shaded and protected from winds while it is held in the field. When possible, pick fruit in the cool of the day.
A cool room is essential. Cool berries before packing and store at 0°C. Market as soon as possible after harvest. Only pack fresh, sound fruit of uniform colour. Berries showing even slight damage should be rejected, as these can deteriorate rapidly and spoil the entire pack.
Strawberries are most often packed in clear plastic-lidded punnets. The most popular size holds about 250g of fruit but fruit may also be sold in 500g trays or loose. Two sizes of 250g punnets exist, one designed to be packed firmly, the other to have the fruit placed in without packing, thus saving on labour costs. Mark the punnets with a sticker stating the grower’s name, address and the minimum weight of the pack. The sticker should be approved by the National Measurement Institute before printing.
Two-hundred and fifty gram punnets are marketed in cardboard trays, which normally hold 12 punnets.