Cassava: The tropical potato

The cassava, with botanical name Manihot esculenta, is a useful plant from the spurge family (Euphorbiaceae) and has been in cultivation for thousands of years. Cassava originated in Brazil, but arrived in Guinea aboard Portuguese slave traders as early as the 16th century, and from there to the Congo, quickly establishing itself in Indonesia as well. Today, it is found in tropical areas worldwide. Its cultivation is so widespread because cassava, also called maniok or yuca, is an important basic food for people around the globe. Its starch-rich root tubers are a healthy and nutritious food whose importance increases in times of climate change, as the edible plant can withstand both heat and drought.

What does the cassava plant actually look like?

Cassava is a perennial shrub that grows up to three meters (10 ft) high. It forms long-stalked, palmate leaves that visually resemble the foliage of hemp. The terminal white flowers are in panicles and are mostly male, but a small number are also female, the plant is therefore monoecious. The fruits of the cassava are distinctively shaped 3-fold capsules and contain the seeds.

However, the most interesting thing about cassava is its large taproots, which form cylindrical to cone-shaped edible tubers by secondary growth in thickness. These grow to an average size of 30 to 50 centimeters (12 to 20 in), sometimes even 90 (36 in). Their diameter is 5 to 10 centimeters (2 to 4 in), resulting in an average weight of 4 to 5 kilograms (8 to 10 lbs) per tuber. The cassava tuber is brown on the outside and white to slightly reddish on the inside.

Where does maniok grow?

As food and for commercial cultivation on a large scale, cassava can only be cultivated in the tropics. Geographically, it can be narrowed down to the area between 30 degrees north and 30 degrees south latitude. Its main areas of cultivation, besides its native Brazil and South America in general, are in Asia and Africa.

To thrive, cassava requires a warm and humid climate with temperatures around 27 °C / 81 °F. In the best growing areas, the average annual temperature is 20 °C / 68 °F. In terms of rainfall, the cassava bush needs at least 500 milliliters, below which the tubers become woody. In addition, sufficient light and sun are essential. However, the tropical plant has hardly any soil requirements: sandy-loamy, loose and deep soils are completely sufficient.

How poisonous is cassava?

Typical of spurge plants, cassava also has so-called milk tubes running through all parts of the plant. The viscous, milky plant sap contains the toxin linamarin, a hydrocyanic acid glycoside, which releases hydrocyanic acid in conjunction with the enzyme linase, which occurs in the cells. Raw consumption is therefore strongly discouraged! How high the content is depends on the variety and local growing conditions. Basically, the higher the starch content, the more toxic the cassava.

How can cassava be harvested and stored?

Cassava can be harvested all year round, and the cultivation period is between 6 and 24 months. Usually, however, the tubers can be harvested after about a year, with sweet varieties being ready for harvest sooner than bitter ones. You can tell when the time is right when the foliage changes color ,this is when the tuber is fully formed and the starch content is at its highest. The harvest period lasts several weeks, as the tubers do not ripen at the same time.

Cassava is very difficult to store: it begins to rot after only two to three days and the starch content decreases. The latter also occurs if the tubers are left in the ground for too long. They must therefore be harvested immediately, processed further or appropriately cooled or waxed for preservation.

What does cassava taste like?

Cassava tubers do not have a significant flavor of their own; they taste slightly sweet, but are not comparable to sweet potatoes (batata) or even our native potatoes. A great advantage of the tubers, apart from their high nutritional content, is that they are naturally gluten-free and can therefore be eaten by people with grain allergies. These benefit especially from the cassava flour, which can be used for baking in a similar way to wheat flour.

Is cassava healthy?

The toxins in cassava can be easily removed from the tubers by drying, roasting, frying, boiling or steaming. After that, cassava is a nutritious and very healthy food that can be used in many ways in the kitchen. The main ingredients at a glance:

• Water, protein and fat.
• Carbohydrates (more than twice as much as potatoes)
• Dietary fiber, minerals (including iron and calcium)
• Vitamins B1 and B2
• Vitamin C (content about twice as high as in potatoes, as high as in sweet potatoes, about three times as high as in yams)

How can cassava be prepared?

The tubers of cassava can be prepared in many ways, each growing country has its own recipes. But first they are always washed and peeled. After cooking, they can be pounded to a pulp, used to make creamy sauces, drinks or, very popular in South America, baked into patties. Roasted and fried in butter, they make a tasty side dish for meat dishes, called “Farofa“. In Sudan, cassava is preferably eaten sliced and deep-fried, but cassava fries are also increasingly enriching the international menu. In Asia and South America, by the way, the leaves of the shrub are also used and prepared as a vegetable or used as animal feed. They can even be exported in the form of dried tuber for livestock. The well-known tapioca, a highly concentrated starch flour, is also made from cassava. Gari, an instant powder found mainly in West Africa, is made from the grated, pressed, fermented and dried tubers. Since cassava cannot be stored, making cassava flour is the tried and true method of preservation. As “Farinha“, the flour is shipped from Brazil, among other places, all over the world.

Can maniok be grown in temperate climate?

Cassava is grown from cuttings that are inserted into the soil at a distance of 80 to 150 centimeters (32 to 60 in). However, these are difficult to obtain in most countries because they are difficult to transport. The tropical potato can therefore usually only be admired in botanical gardens. With a little luck, however, the plant can be found online or at specialized nurseries.

As a normal houseplant, the shrub is difficult to cultivate, but in the winter garden or the temperate greenhouse, you can certainly keep it as a decorative foliage ornamental plant in the tub. In itself, cassava is quite undemanding and robust, in summer it can even briefly move outdoors to a sheltered place on the balcony or terrace. And with pests or plant diseases it has no problems anyway, only aphids can occur sporadically.

The location should be sunny, the more light the shrub gets, the more often it needs to be watered. The substrate should be permanently moist, even in winter, when it can still manage with less watering due to cooler temperatures. Year-round temperatures of at least 20 °C / 68 °F, never colder than 15 to 18 °C / 59 to 64 °F in winter, are absolutely necessary for successful cultivation. From March to September, fertilizer should be added to the water once or twice a week. Dead plant parts are removed when they are completely wilted. Plant the cassava in humus-rich quality potted plant soil and mix it with expanded clay or gravel for better drainage to avoid waterlogging. Because of its extensive roots, cassava requires a very large and deep plant pot and usually needs to be repotted annually. However, there is a small damper: tubers from our own cultivation, even with optimal care, you will hardly be able to harvest.