Brassica

The plants in this family have been selectively bred to produce the various plant parts used as food.

(List members of the Brassica family of plants)

Types of brassicas:

• Broccoli

• Cabbage

• Kohlrabi

• Cauliflowers

• Brussel sprouts

• Turnips

• Radishes 

• Broccolini

Open Pollinated Seeds, Hybrids

• Seeds from a hybrid variety can be collected to replant in future years

• Open-pollinated varieties have lower production than hybrids.

Broccoli (common varieties)

(Name three important current commercial varieties of the Brassica crop studied.)

1. Corato: blue-green in colour, has medium to fine bead size and takes 9-11 

weeks to grow. It has very few leaves to clean.

2. Dynasty: deep green in colour, has medium bead size and takes 10-12 weeks to 

grow. It is highly adaptable.

3. Imperial dark green in colour has fine bead size and takes 11-12 weeks to grow. It 

has good white blister tolerance.

Soil

(State the specific climatic and soil (physical and chemical) requirements of this crop.)

• The soil pH should be 6.0 - 6.5 

• The preferred soil is loam or sandy loam

• Good drainage is important for growing broccoli

Climate

• Broccoli should be planted in a sunny position

• Cool weather

• Broccoli is suited for all climatic zones

If the weather is too warm or hot, it can cause issues such as bolting and poor head quality. Cold weather can damage the heads of the plant and kill young seedlings. 

If there's not enough water, the broccoli plant will dry out and die, and if there is too much then the roots may rot and develop fungal diseases. It can also not get enough oxygen.

Calendar of Operations

(Outline a calendar/sequence of operations undertaken to grow the selected crop and match it to a scale/time frame.)

Brassicas at James Ruse are grown from seedlings purchased in late February. Seeds are sown into punnets in January and the seedlings are big enough for transplanting at 4 - 6 weeks old. Ideally the soil pH is tested in January and if needed the pH can then be adjusted by adding lime. Fertilisers such as compost and blood and bone are added to the soil in January/February and the garden beds are mounded by students in February.

After transplanting the seedlings are mulched to prevent weed growth and water loss. Students water and weed the plots regularly and may add fertiliser. If insect pests are detected then pest control is carried out as needed.

Harvesting occurs when the crop is mature in April/May. Marketing operations may include selling of produce to the school canteen, adverts in the school newsletter, excess produce to be sent to disadvantaged people, and students to bring produce home.

Summarised:

January: seeds are sown into punnets, soil pH is tested and adjusted if needed.

February: seedlings are purchased, fertilisers are added, garden beds are mounded.

March: seedlings are transplanted.

February - May: plots are mulched, watered and weeded, fertilisers and pest control may be needed.

April/May: harvest the mature crop, sell and distribute harvest

Pest - Cabbage White Butterfly

(Outline for a major insect or invertebrate pest (for example Cabbage white butterfly): the life cycle, effect on the plant/symptoms, management in a commercial setting.)

• Eggs are found on the underside of host leaves and they take around 4 days to hatch

• Caterpillars are found on food plants, and they become pupae after 17 days

• Pupae are found away from food plants and they hatch into butterflies after 8 days

Effect of cabbage white butterfly on broccoli plants:

• The plants will have less growth

• The leaves will be damage so they will photosynthesise less

• The plant will produce less marketable product

• The plant may be covered in frass

Managing cabbage white butterflies:

• once harvesting is done, plough in old crop residues

• spray with appropriate chemicals, targeting active small caterpillars

• (natural control agents) bugs and parasites, such as lacewings, spiders, ladybird, beetles

Use of DiPel

• Use 1g of DiPel with 1L of water

• Avoid contact with skin and eyes, and wash hands after use

• It takes 3 days to kill caterpillars

Diseases - Downy Mildew

(Outline for a major disease: the life cycle, effect on the plant/symptoms, management in a commercial setting.)

Downy mildew is caused by the fungus H. parasitica. Its spores are created at night on old leaves and spread during the day by wind and rain. They can survive on debris before spreading to a crop.

• Symptoms: patches of white spots with black dots on leaves.

• preventing/control: Remove crop debris after harvest, rotate with non-brassicas, an application of appropriate fungicide. 

Harvesting

(Describe the harvesting of the crop: stage of growth, method, post harvest treatment.)

Broccoli can be harvested when some of the buds start to move away from the central head. 

• The desired colour for broccoli heads are green

• Broccoli has the highest levels of starch at 3pm.

• Broccoli head damage and stem blackening can be reduced by harvesting with the leaves on

• Storing at 0°c will result in the lightest leaf scar

Commercially, broccoli is harvested using a specific cutting knife and is cut one inch (2.54cm) from the crown. These are then transported and kept at very cold temperatures (0 c) with ice.

Marketing

(Outline the marketing of the crop, including: preparation of product, location of market.)

1. broccoli is transported into a packing shed.

2. They are moved onto moving belts and their stem is cut off using human power or machine.

3. They are packed and weighed. They can be put in boxes or wrapped in plastic (cling wrap).

4. They are transported out of the packing shed.

general criteria that are used to define good produce quality.

• good colour (blue/purple green florets, light green stem). No yellow or brown on florets, leaves or stem.

• compact and crisp heads (size 12-15cm)

• short stems

• no live insects, diseases, damage

• very few minor damages (scuffing, breaks, hollow stalks)

Consumption

(State the role of this vegetable in the diet of humans.)

Broccoli contains:

• vitamin c, e and b

• beta carotene

• folate

• minerals (iron and calcium)

• Fibre

Nutrition information: Broccoli (microwave cooked)

Serving size: 70g

                            Per serving     Per 100g

Energy               62 kJ                 89 kJ

Protein              2.2 g                 3.2 g

Fat  total            0.3 g                 0.4 g

      saturated       -                        -

Carbohydrate

        total           0.9 g                 1.3 g

        sugars       0.9 g                 1.3 g

Dietary fibre   2.0 g                 2.9 g

Sodium             9 mg                13 mg