How to Grow Cassava in Florida

For Floridians, cassava (Manihot esculenta) represents a starch that takes less space, time and effort to grow than grains demand. The small trees, which need eight frost-free months to produce their edible, potato-like roots, are reliably perennial in U.S. Department of Agriculture plant hardiness zones 10 and higher. Yet even in North Florida, preserving part of the tree's slender trunk, or stem, makes it possible to grow cassava as a yearly crop without reinvesting in new propagation material.

Soil testing kit or portable soil test meter

Compost

5-10-10 fertilizer

Spade

Garden hose or drip irrigation system

Machete or ax

Trowel

Test your soil before adding garden amendments. Cassava isn't fussy about pH, but some Florida soils have normal to excessive amounts of phosphorus.

Work a 4-inch layer of compost and 1 pound of 5-10-10 fertilizer into the top 12 inches of soil for each tree you will be planting. If you have normal to high phosphorus -- the middle number -- buy 5-5-10 or 5-0-10 instead.

Plant stem cuttings in early spring. Set each one about 3 to 4 inches deep, with the remaining several inches of the stem cutting left above the soil line. If you are planting several cassava trees, set the stem cuttings so that they are 4 feet apart.

Give the trees about 1 inch of water a week during times of low rainfall. Cassava will tolerate drought, but the roots will be less woody if the soil doesn't dry out between watering sessions.

Grow cassava trees at least eight months before harvesting roots. They do not need to be harvested within a year, but the roots may become less palatable if they are several years old.

Harvest cassava in late fall by chopping down the thin stem to about 12 inches above the soil line with a machete or ax, then lifting the stem to pull the roots up. If the roots don't come up easily, dig them carefully with a trowel to avoid nicking them with a sharp spade.

Cut the stems of uprooted trees in 8- to 12-inch sections. In USDA zones 10 and 11 you can immediately replant these stem cuttings. In zones 8 and 9, bring the stem cuttings inside until early spring. Alternatively, set them aside outdoors, covered with hay or earth.

Choose newer cassava cultivars known as "sweet" cassava types. They require less processing before they are edible.

The same compounds that make raw cassava toxic for people also make the tree able to defend itself against pests and diseases. Along with its ability to tolerate drought and infertile soil, its resistance to these problems adds up to a relatively trouble-free crop.

In USDA zones 10 and 11, unharvested cassava trees are evergreen. In USDA zones 8 to 9, the unharvested trees will die back, but often regrow in the spring.

You may also know cassava as tapioca plant, manioc or yuca. Along with cassava, all are common names for Manihot esculenta.

Both sweet and bitter cassava types contain cyanide. Peeling them and boiling them in at least one change of water before the regular preparation is the only way to ensure they won't be toxic when consumed.