Vegetable Production and Protected Cultivation
Domain 3 tests vegetable production from nursery to harvest and the use of protected structures to modify the crop environment. The exam expects practical spacing, seed rate, staking, rotation and greenhouse management, not just definitions.
Core rules
- Classify vegetables by the edible part: root, stem, leaf, flower, fruit and seed. This guides nutrition and harvesting advice.
- Raise healthy seedlings in a nursery, then transplant at the correct stage. Harden seedlings before transplanting to reduce shock.
- Crop rotation interrupts soil-borne disease cycles. Avoid planting the same family in the same bed season after season.
- Staking and pruning improve light penetration and keep fruit off the soil for crops such as tomato and capsicum.
- Protected cultivation includes shade nets, plastic tunnels, greenhouses and insect-proof net houses. Each modifies temperature, light, humidity or pest entry.
- Ventilation controls humidity and temperature. Fertigation delivers soluble nutrients through irrigation, but concentration and pH must be checked.
Worked example
A 20 m × 10 m protected house is planted at 40 cm × 25 cm. Area = 200 m². Each plant occupies 0.40 × 0.25 = 0.10 m². Plant number = 200 ÷ 0.10 = 2,000 plants. If a 1 m path is removed along the length, the planted area falls, so the actual number is lower. Always convert centimetres to metres before dividing.
Traps that cost marks
Do not assume shade net percentage is the same as light reduction in every crop. Do not recommend the same temperature for all greenhouse crops. Do not confuse open-pollinated seed with hybrid seed. Do not ignore pollination and ventilation in protected structures.