How to grow cassava
Overview
Cassava (Manihot esculenta) is a tropical root vegetable grown for its edible, high-carbohydrate tubers. It is a staple in many cuisines and also yields leaves that can be cooked. Growers must ensure roots are properly cooked to remove cyanogenic compounds.
Varieties
- Atherton — A popular sweet cassava variety in Australia, known for its good flavour and reliable yield.
- KU50 — A high-yielding Thai cultivar suitable for tropical and subtropical regions, with good drought tolerance.
- MCol 2215 — A Colombian variety valued for its high starch content and resistance to common pests.
Soil Preparation
Cassava prefers slightly acidic to neutral soil (pH 5.5–7.0), sandy loam or loamy soil with good drainage. Amend heavy soils with organic matter or plant in raised beds to prevent waterlogging. Incorporate well-rotted manure or compost before planting for fertility.
Growing Guide
Plant cassava in full sun in well-drained soil, spacing cuttings 1 m apart in rows 1.5 m apart. Insert stem cuttings (20–30 cm long) vertically so two nodes are buried. Water sparingly until shoots appear, then maintain moderate moisture. Harvest roots 9–12 months after planting when leaves begin to yellow.
Care
Feed with a potassium-rich fertiliser once during active growth; avoid high nitrogen as it promotes leafy growth at the expense of roots. Mulch around the base to conserve moisture and suppress weeds. No pruning is required; remove any diseased foliage as needed.
Companion Planting
Cassava grows well with leguminous cover crops like beans, peanuts, and cowpeas that fix nitrogen. Avoid planting near other root crops such as yams or potatoes to reduce competition for space and nutrients.
Common Pests & Risks
Cassava in Australian gardens is relatively pest-free but may be affected by mites or mealybugs in dry conditions. Control mites with neem oil or insecticidal soap, and manage mealybugs by encouraging natural predators like ladybirds. Avoid overwatering to prevent root rot.
Harvesting
Harvest cassava roots when they are 20–30 cm long and the leaves begin to yellow and drop, typically 9–12 months after planting. Gently loosen the soil around the base and lift the root mass by hand or with a fork. Roots can be left in the ground for several months if needed.
In the Kitchen
Cassava roots must be peeled and thoroughly cooked to remove toxic cyanogenic compounds. Boil, bake, fry, or steam the flesh; it is used as a side dish, in stews, or ground into flour for baking. Leaves are edible after prolonged boiling but should be consumed in moderation.
Troubleshooting
Yellowing leaves: often due to nitrogen deficiency or overwatering; apply a balanced fertiliser and adjust watering. Wilting: can indicate water stress or root rot; check soil moisture and ensure drainage. Stunted growth: cold or poor soil; wait for warm weather and enrich soil. Leaf spots: fungal infections; remove affected leaves and improve air circulation. Mealybug infestations: spray with neem oil or insecticidal soap.