Vegetable · Euphorbiaceae
Cassava
Manihot esculenta
A rewarding warm-season root that pays off with care and proper processing.
Full sun
Every 7–14 days
59–95°F · 15–35°C
240–360 days
Overview
Cassava (Manihot esculenta) is a woody tropical shrub in the spurge family (Euphorbiaceae), and gardeners grow it for its starchy roots. It traces back to South America, where people have cultivated it for thousands of years, and today it stands as a major staple crop across warm regions.
Give it room and it rewards you: plants climb to 5 to 10 feet (1.5 to 3 m) and spread 3 to 6 feet (90 to 180 cm), growing at a steady, moderate pace. It is a perennial that thrives outdoors only, not in containers, and it shrugs off dry spells once established.
The catch is safety, and it is a serious one. Every part of the plant holds cyanide-forming compounds, so cassava is only safe to eat after peeling, grating or soaking, and thorough cooking. Handle that step right and you have a genuinely satisfying crop to grow.
Care
The short version: plant stem cuttings in full sun and warm, well-drained sandy loam at pH of 5.5 to 6.5, keep temperatures in the 59°F to 95°F (15°C to 35°C) band, and water young plants to get them going before easing off, since cassava is drought-tolerant once established. Feed a balanced NPK with potassium at planting, harvest roots 8 to 18 months in, and always peel, soak or grate, and cook before eating.
Light
Cassava loves the sun, so give it full sun for the strongest growth and best root development. It will get by in partial shade, but expect more reward where the light pours in.
Water
Water young plants steadily to get them established, then back off, because cassava turns highly drought-tolerant once established. In dry spells, water every 7 to 14 days and let the top 3cm dry between drinks. Steer clear of waterlogged soil, which brings on root rot and drags down tuber quality.
Soil
Plant into well-drained sandy loam at a pH of 5.5 to 6.5. Sharp drainage is the priority here: it keeps the roots healthy and the tubers worth harvesting.
Temperature
Keep cassava in the 59°F to 95°F (15°C to 35°C) range where it grows happily. It is frost-tender, and a touch of frost blackens the foliage fast, so grow it strictly within the frost-free season.
Humidity
Average humidity of 40% to 70% suits cassava just fine. It copes with drier air without fuss, so there is no need to chase humidity for this crop.
Feeding
Feed a balanced NPK with adequate potassium to power root development, applied at planting only. That early boost sets up the tubers for the long bulking season ahead.
Pruning
Cassava asks for very little here. Trim the lower lateral shoots to channel growth, cut back any damaged or frost-killed stems, and save the healthy stems as cuttings to replant next year.
Repotting
not typically container-grown
Size & spacing
Plan for plants that reach 5 to 10 feet (1.5 to 3 m) tall and spread 3 to 6 feet (90 to 180 cm). Space them with that mature footprint in mind so each shrub has room to bulk its roots.
When to plant
Cassava runs on the warm season, so timing keeps it simple. Plant your stakes once frost danger has passed and the soil has warmed, then let the roots bulk for 8 to 18 months before harvesting ahead of the first frost.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Plant woody stem cuttings (stakes) after all danger of frost has passed and soil is warm.
- Harvest: Harvest roots 8-18 months after planting, once tubers have bulked.
Hardiness
USDA hardiness zones: 9–11
Temperature: down to -7°C
Troubleshooting
Most cassava trouble traces back to three culprits: a virus carried by whiteflies, soggy soil at the roots, and a cold snap. Spot the signs early and each one is manageable, so here is what to look for and how to set things right.
Mottled, twisted leaves point to cassava mosaic virus
When foliage breaks out in a yellow-green mosaic and the new growth comes in warped and stunted, cassava mosaic virus has taken hold. Whiteflies carry it from plant to plant, and infected cuttings pass it straight into next season. There is no cure once a plant has it, so pull and destroy anything mottled and start clean with certified virus-free stakes.
Fix:
- Remove and destroy infected plants
- Use virus-free planting material
- Control whitefly vectors
Blackened, collapsing growth means frost has struck
Cassava is frost-tender, so a single night near or below freezing blackens the foliage and stems and drops the plant fast. Harvest the roots before frost arrives, and in all but the warmest zones treat the crop as a single warm-season run, timing planting and harvest to fit the frost-free window.
Fix:
- Harvest roots before frost
- Protect or relocate if possible
Soft, smelly tubers and a wilting plant signal root rot
Roots that turn soft, discolored, and foul-smelling while the plant wilts above ground are classic root rot, and the trigger is almost always waterlogged or poorly drained soil. Plant on ridges or a well-drained site, ease off the water, and dig your roots promptly once the tubers have bulked.
Fix:
- Improve drainage
- Avoid overwatering
- Harvest promptly once mature
Toxicity
This is where cassava demands real respect. Every part holds cyanogenic glycosides that release hydrogen cyanide when the tissue is damaged, which makes raw or half-processed cassava genuinely dangerous to people and animals. Keep raw plant material well away from children and pets.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Severe
Watch for drooling, vomiting, and labored breathing, along with dilated pupils, weakness, convulsions, and collapse. This is an emergency that needs a vet right away.
Dogs Severe
Drooling, vomiting, and breathing trouble come on quickly, followed by staggering and seizures. Treat any suspected nibble as urgent and call a vet.
Horses Toxic
Expect fast, distressed breathing, trembling, and stumbling; a large dose can be fatal. Get veterinary help without delay.
Rabbits Toxic
Their small bodies handle cyanide poorly, so weakness, gasping, and twitching can set in fast. Even a little is serious and warrants quick care.
Livestock Severe
Cattle, goats, and sheep may show rapid breathing, drooling, and staggering, then muscle tremors, convulsions, and collapse. Move them off the plant and call a vet.
Birds Toxic
Poultry and pet birds show labored breathing and sudden weakness, and their small size makes even a modest amount serious. Act fast and reach a vet.
People Caution
A staple for millions, but only after peeling, grating or soaking, and cooking. Raw or half-processed roots and leaves release cyanide that brings on vomiting and dizziness, and steady under-processing can lead to konzo paralysis. Never eat any part raw.
Proper processing (peeling, grating/soaking, and thorough cooking) drives off the cyanide and renders cassava safe to eat; the raw plant and unprocessed roots/leaves are dangerous. Keep raw plant material away from children and animals.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Cassava comes in two broad camps, and the difference is all about how much cyanide-forming compound the root carries and where it sits. Both still need proper processing, so know which one you are growing.
Sweet cassava
Carries fewer cyanide-forming compounds, and most of what it does hold sits in the peel. Still, you must peel and cook it before it goes on the plate.
Bitter cassava
Cyanide-forming compounds run throughout the root, so it demands heavy processing: grating, soaking, fermenting, and cooking before it is safe.
How to propagate
Cassava propagates the easy way: from stem cuttings, not tubers or seed. Take stakes from mature, healthy stems, plant them as the warm season opens, and watch new growth push out in just a few weeks.
Stem cuttingsEasy
Plant mature woody stem cuttings (stakes) at the start of the warm season after frost danger has passed. · 2 to 4 weeks for sprouting and rooting
Skip the tubers and seed and go straight to stakes: cut 20 to 30 cm lengths from mature, healthy stems and set them at the start of the warm season. Fresh shoots and roots break in about 2 to 4 weeks.
Myths
A quick boil makes any cassava safe to eat.
Bitter types need peeling, grating, soaking, and a long cook to be safe. A brief boil leaves far too much cyanide behind, and under-processing over time builds toward cyanide poisoning and konzo paralysis.
Only the roots of cassava are poisonous.
The leaves carry the same cyanide-forming compounds as the roots. Both have to be properly processed before any person or animal can safely eat them.