Harvesting of Horticultural Crops – SS1 Horticulture and Crop Production Lesson Note (Second Term)

Harvesting is the gathering of mature crops from the field or garden at the right stage of ripeness.

Behavioural objectives

By the end of the lesson, students should be able to:

1. define harvesting and state why it is special in horticulture;
2. name the tools used for harvesting horticultural crops and state their uses;
3. describe the visual, physical and time signs that show a crop is ready to harvest;
4. compare manual and mechanical harvesting;
5. list and explain the steps of post-harvest handling.

What is harvesting?

Harvesting is the process of gathering mature crops from the field.

• Horticultural crops: vegetables, fruits and flowers grown in gardens or on small farms, such as tomato, pepper, Ugwu and mango.
• Harvesting too early: the fruit is sour, unripe and poor in taste.
• Harvesting too late: the produce becomes over-ripe or rotten.
• Soft produce: unlike maize or cocoa, tomatoes and spinach bruise easily when handled roughly.
• Bruised produce: it changes colour and buyers reject it.

Why is harvesting special in horticulture?

Harvesting is special in horticulture because the crops are soft, perishable and often picked many times.

• Multiple harvests: you do not harvest only once. Peppers may be picked from the same plant every week for two months.
• Delicate touch: most horticultural crops are harvested by hand to avoid damage.
• Perishability: once cut from the plant, the produce quickly loses water and spoils, so you must work fast.

What are the general rules for harvesting?

• Time of day: harvest in the cool of the morning or late afternoon, not in the hot midday sun.
• Clean tools: use clean, sharp tools so that cuts are neat and disease does not spread.
• Gentle handling: place produce in containers, do not throw it.
• Quick shade: move the harvest into the shade at once.

What tools are used for harvesting?

There are four main groups of harvesting tools: secateurs, hand trowel or garden fork, knife or sickle, and baskets or crates.

Heavy machines are not used in small gardens. Small, sharp and clean hand tools are used instead.

1. Secateurs (pruning shears)

• Use: cutting the stalks of fruits like mangoes and clipping flower stems.
• Why: it gives a clean cut that does not tear the plant’s skin.

2. Hand trowel or garden fork

• Use: lifting root crops like carrots or onions out of the soil without breaking them.

3. Sharp knife or sickle

• Use: cutting leafy vegetables like Ugwu or Soko.

4. Harvesting baskets or crates

• Use: carrying the harvest from the field.
• Tip: plastic crates with holes are better than sacks because air flows through them and keeps the vegetables cool.

How do you know when to harvest?

Maturity indices are the signs that show a crop is ready to be harvested.

There are three kinds of signs: visual signs, physical signs and time.

1. Visual signs (looking)

• Colour change: tomatoes turn from green to red, and oranges turn yellow.
• Size: okra is ready when it reaches the size the market likes.
• Drying up: onion and garlic leaves turn brown and fall over.

2. Physical signs (touching and listening)

• Weight and sound: a ripe watermelon feels heavy and sounds hollow when tapped with the knuckle.
• Ease of snapping: a fresh okra tip snaps when bent. If it only bends, the pod is too old and fibrous.

3. Time (counting)

• Days since planting: each crop takes a known number of days to mature, so some farmers count the days from planting.
• Example: a farmer may say, “This pepper is 90 days old, it must be ready.”
• Limit: counting days alone is not enough, so check the visual and physical signs too.

What are the methods of harvesting?

There are two methods of harvesting: manual harvesting and mechanical harvesting.

1. Manual harvesting (by hand)

Manual harvesting is gathering crops by hand or with simple hand tools, and it is the most common method in horticulture.

• Hand picking: plucking fruits like peppers or garden eggs with the fingers.
• Digging: using a fork to lift root crops.
• Cutting: using a knife for leafy vegetables.

2. Mechanical harvesting (by machine)

Mechanical harvesting is gathering crops with machines, and it is used on very large farms for crops like beans or potatoes.

What is the difference between manual and mechanical harvesting?

What is post-harvest handling?

Post-harvest handling is the care given to crops after harvest to keep them fresh for the market.

The work does not end when the crop leaves the ground. Follow these four steps in order:

1. Cleaning: remove soil from carrots or onions. Do not wash tomatoes unless you will sell them at once, as water can make them rot faster.
2. Sorting and grading: put big, healthy fruits together and the small or slightly bruised ones in a different pile. This helps you set different prices.
3. Cooling: keep the harvest in a cool, shady place. Never leave harvested vegetables under the direct Nigerian sun, or they will “faint” (wilt) quickly.
4. Packaging: arrange the produce neatly in baskets or crates. Do not pack too tightly, or the ones at the bottom will be crushed.

Which tool and maturity sign suit each crop?

Each crop has its own best tool and sign of maturity, as shown in the table.

Evaluation

1. Define harvesting.
2. State three reasons why harvesting is special in horticulture.
3. Name the tool you would use to harvest Ugwu and the tool you would use to lift carrots.
4. Give two signs that okra and onions are ready to harvest.
5. State one advantage and one disadvantage of mechanical harvesting.

Assignment

List the four steps of post-harvest handling and explain, in one sentence each, why each step is important.