|PLANT TYPE: Annual
SCIENTIFIC NAME: Stevia rebaudiana
ZONE / HARDINESS: Annual – not applicable
MATURE PLANT SIZE: 24 inches high
LIGHT: Full Sun – but not hot weather
SOIL TYPE: Light, sandy, open, well drained soil
pH RANGE: 6.7 to 7.2
KNOWN PESTS: N/A
KNOWN DISEASES: N/A
Although stevia is not considered an easy herb to grow, it has proved to be quite adaptable and capable of being cultivated in climate zones as diverse as Florida and southern Canada.
If you haven’t grown this herb before, it does well in containers. Can be used as a ground powder or liquid in baking or desserts
Surface sow seed 8 weeks before last frost date or anytime if you plan to grow inside. Germinate using gentle bottom heat. Provide good drainage and do not overwater. Plant outside after all risk of frost is past, 8 inches apart into a full sun location. If you wish to overwinter the plants inside, remove from your garden before the temperature drops below 10 degrees C. Excellent in containers. Use the leaves, fresh or dried, directly in hot drinks. You can use ground powder or liquid in baking or desserts. Grows 24 inches high.
PROPAGATION / SOWING:
It is best to propagate stevia plants from cuttings or tissue culture from a plant that has proven to be successful. Growing stevia from seed normally has a very low germination success; sometimes only 10%. You can increase the odds if you select the very dark seeds and plant only those seeds – your germination should exceed 85%. Stevia grown from seed may or may not be sweet.
CARE & GROWING:
Stevia should be planted in the spring after the soil temperature reaches 65 deg F., in full sun and in a light, sandy, open, well drained soil with neutral pH. In southern states, stevia will require some filtered afternoon shading. Use a standard garden fertilizer. Do not use a lawn fertilizer or fertilizers with high nitrogen. Adding extra Boron will help keep the Stevioside level high. If soil could be mounded up into a raised bed, this would be even better. Apply a layer of mulch, such as grass clippings, or bark mulch. This will help keep roots cool, preserve water, keeps the leave clean from soil (prevents dirty taste in green powder) and hold down weeds. Avoid weeding around mature stevia plants as their brittle branches are easily broken. Avoid overwatering after transplanting and in winter as houseplant. Keep evenly moist during summer heat. Drip or soaker hose are very effective for summer watering.
Harvest entire plant as flower buds appear. Harvest only in the morning for highest glycoside /sugar content, whether pinching tips or entire plants. The full harvest will occur in late September or early October. Because it is a member of the Aster family, once flowering has begun, not a single normal leaf will be produced. Removing flower heads is not effective. Failure to harvest plants before several flowers have opened, will allow these flowers to impart a bitter/dirty flavor to the leaves. Harvesting is done by cutting the entire plant at the base. With a rubber band, tie loose branches together and hang upside down to dry under warm, dark, drafty conditions for 2-4 days. Avoid using food dehydrators or open oven doors as this will also tend to cause a bitter flavor. Remove any small branches and grind leaves into powder using an electric coffee grinder for 25-30 seconds. Food processors are not as effective because of their slow RPMs. Dried green stevia powder will last almost indefinitely or at least until the next harvest.
Leaves – raw or cooked. A very sweet flavour. The leaves contain ‘stevioside’, a substance that is 300 times sweeter than sucrose. Other reports say that they contain ‘estevin’ a substance that, weight for weight, is 150 times sweeter than sugar. The dried leaves can be ground and used as a sweetener or soaked in water and the liquid used in making preserves. The powdered leaves are also added to herb teas. The leaves are sometimes chewed by those wishing to reduce their sugar intake. The leaves can also be cooked and eaten as a vegetable. Many who hesitate to consume artificial food additives may prefer stevia because it is all natural. Stevia is calorie free, and therefore does not impact blood sugar levels, unlike sucrose (refined sugar). Stevia, when used in place of sugar, may also reduce the incidence of tooth decay.