Vegetables
Senior 1 · Agriculture
Vegetables
Lesson 3 of 5
24 min
Let's begin
Keza and her brother plant the same cabbage seedlings on the same day. Keza digs deeply, mixes in compost, spaces her plants with a garden line, mulches and weeds on time. Her brother plants into rough, weedy soil wherever there is a gap. Three months later Keza sells firm, heavy heads while her brother's plants are small, crowded and eaten by caterpillars.
Good seedlings are only the start. The harvest depends on how the land is prepared, how the crop is planted and how well it is looked after in the field.
| Method | How | Examples |
|---|---|---|
| Broadcasting | Seed scattered evenly over the bed, then raked in | Amaranth (sometimes) |
| Drilling | Seed sown thinly along shallow furrows in rows | Carrot, beetroot, radish |
| Dibbling (hills) | A few seeds placed in each hole at fixed spacing, later thinned to the best one or two | Pumpkin, cucumber, French beans |
| Transplanting | Nursery seedlings planted out at fixed spacing | Tomato, cabbage, onion, eggplant, pepper |
Correct spacing gives each plant enough light, water and nutrients, lets air move between plants (reducing disease) and leaves room to work. Typical spacings (illustrative; follow the seed packet or extension advice): tomato 90 cm × 50 cm (staked); cabbage 60 cm × 50 cm; onion 30 cm × 10 cm; carrot 30 cm between rows, thinned to 5 cm.
The number of plants that fit on an area is:
plant population = area ÷ (distance between rows × distance between plants), with all lengths in metres.
Question: Mugisha will plant cabbage on 0.05 ha at 60 cm × 50 cm. (a) How many plants does he need? (b) He raises 10% extra seedlings to replace any that die. How many should he raise?
(a) Area = 0.05 ha × 10,000 m² per ha = 500 m².
Space per plant = 0.6 m × 0.5 m = 0.3 m².
Population = 500 ÷ 0.3 ≈ 1,667 plants.
(b) 1,667 × 1.1 ≈ 1,834 seedlings (about 1,850 to be safe).
Tip
Memory hook for field care: "Gap, Thin, Water, Weed, Mulch, Stake, Feed, Protect."
Exam technique: in plant-population questions, convert every length to metres and every area to square metres first (1 ha = 10,000 m²). Most wrong answers come from mixing centimetres and metres.
Distinguish between primary and secondary cultivation.
Solution: Primary cultivation is the first, deep digging that breaks and turns the soil and removes weed roots. Secondary cultivation follows it, breaking clods and levelling the soil to make a seedbed of the right tilth.
Give three benefits of mulching a tomato crop.
Solution: Any three: conserves soil moisture; suppresses weeds; keeps the soil cool; stops rain splashing soil and disease spores onto leaves; adds organic matter.
Onions are planted at 30 cm × 10 cm. How many plants fit on 60 m²?
Solution: Space per plant = 0.3 × 0.1 = 0.03 m². Population = 60 ÷ 0.03 = 2,000 plants.
Why should weeding around vegetables be shallow?
Solution: Many vegetables have shallow roots; deep hoeing cuts them, stressing the plants and opening wounds for disease.
Suggest two ways of reducing bacterial wilt in tomatoes without chemicals.
Solution: Any two: rotate with crops of other families (not eggplant, pepper or Irish potato); use clean, healthy seedlings; uproot and destroy wilted plants; plant resistant varieties; avoid waterlogged fields.
Summary
Sources and credits
This lesson adapts CC BY-SA material and is shared under CC BY-SA 4.0.
