Cassava grows even in poor, dry soils. But when harvested too early, the cassava tubers are small. They are poor in starch, and full of fibres and water.
How does cassava grow?
A few days after planting, the cassava cuttings develop roots which take water and nutrients from the soil. When the first leaves emerge, they absorb sunlight and air. The more the plant takes up sunlight, air, water and nutrients, the more starch will develop in the tubers. Cassava tubers have the most starch 8 to 12 months after planting.
How to grow big, starchy cassava tubers
1. Use improved varieties which resist disease. Some varieties resist drought; others branch early and suppress weeds better. Some varieties mature more quickly.
2. Apply manure or compost. It has nitrogen that cassava needs to grow. Do not leave manure uncovered or on top of your soil, as the nitrogen will evaporate. Age or compost the manure. When aged, it will lose its smell and its heat, but will still have its nutrients. When you plant the cassava, add a handful of manure or compost and close it with soil. This will protect it from washing away in the rain and will feed the roots.
3. Apply mineral fertilizer when you plant, or wait 3 weeks until the roots have developed and can absorb nutrients. You can apply 5 grams of NPK, which is enough to fill a bottle cap. Put this fertilizer with a handful of manure around each plant. Cover the fertilizer with soil so the rain does not wash it away.
4. Grow a legume crop such as cowpea, groundnut, beans or soya beans between the cassava. Sow legumes 4 to 6 weeks after planting the cassava so they do not grow over the young cassava plants. Legumes absorb nitrogen from the air. Legumes grow fast, and suppress weeds.
5. Plant cassava at 1 meter by 1 meter, and grow 2 rows of legumes between the cassava. Or you can plant the cassava plants half a meter apart, and leave 2 meters between rows, to leave more space for legumes.