Tuber Crops SS2 Horticulture and Crop Production Lesson Note

Class: SS2

Subject: Horticulture and Crop Production

What are Tuber Crops?

Tuber crops are plants that store their food (starch) in underground parts of the plant. Unlike maize or beans where we eat the seeds, for tubers, we dig into the earth to find our food. They are the best sources of carbohydrates for energy.

Cassava (The “Reliable” Tuber)

Cassava is the most popular tuber in Nigeria because it can grow in poor soil and survive dry weather.

• Planting Material: We use Stem Cuttings. Don’t use the very top (too soft) or the very bottom (too old). Pick the middle part of a healthy stem.
• Planting Method: Cut the stems into pieces about 20cm to 30cm long. Push them into the ridge at an angle (slanting).
• Spacing: 1m by 1m (100cm×100cm).
• Maintenance: Weed the farm early. Cassava doesn’t like to “fight” with grass when it is young.
• Harvesting: Pull the whole plant out of the ground after 9 to 12 months.

Yam (The “King” of Tubers)

Yam is a prestigious crop. It requires more work and better soil than cassava.

• Planting Material: We use Yam Minisetts or Seed Yams (small whole tubers).
• Land Preparation: You must make big, high heaps or deep ridges. The soil must be loose so the yam can grow big and straight.
• Staking: Yam is a climber. You must provide a tall stick (stake) for the vines to climb so the leaves can reach the sunlight.
• Mulching: Because we plant yams during the dry season, you must cover the top of the heap with dry grass to keep the “seed” cool so it doesn’t “cook” in the hot soil.
• Harvesting: Carefully dig around the tuber with a digging fork after 7 to 9 months when the leaves turn yellow and dry.

Cocoyam

Cocoyam is great because it can grow in shady areas where other crops might struggle.

• Planting Material: We use Corms or Cormels.
• Cultivation: It loves moist soil. In some parts of Nigeria, it is planted in the “valleys” between yam heaps.
• Spacing: Usually 60cm between plants and 90cm between rows.
• Harvesting: Dig up the tubers when the large “elephant ear” leaves start to wither.

Sweet Potato

Sweet potato is the “fastest” tuber. It can be ready to eat in just 3 to 4 months!

• Planting Material: We use Vine Cuttings.
• Method: We plant the vines on ridges. Because the vines “creep” on the ground, they act as a natural mulch, covering the soil and stopping weeds.
• Harvesting: Dig them up as soon as they are mature. If you leave them in the ground too long, “weevils” will start to bore holes into them.

Summary Table for Revision

General Care for All Tubers

1. Loose Soil: Always make sure your heaps or ridges are soft. If the soil is hard like a rock, the tubers will stay small and “stunted.”
2. Mounding: As the tubers grow, they sometimes “pop out” of the soil. Always cover them back with fresh soil to protect them from the sun and pests.
3. Processing: Remember that fresh cassava has a “poison” (cyanide) inside. It must be soaked, fermented, or fried (into Garri) to make it safe to eat.

Teacher’s Classroom Discussion

Ask the students: “If you have a very small piece of land and you are very hungry, which of these four tubers would you plant to get food the fastest?” (Answer: Sweet Potato—because it only takes 3 to 4 months).