Growing Stevia, the Easy Way
It is claimed to be 300 times more sweet then cane sugar and it’s what the doctor advises the diabetics. Leaves of this South American shrub have been used for centuries by native peoples in Paraguay and Brazil to sweeten their yerba mate and other stimulant beverages. And now, there is great interest among Indian farm owners for Stevia, pronounced STEE-vee-uh. Stevia leaves fetch a price of Rs 60 to Rs 120 a kg.
Stevioside, the main ingredient in stevia (the two terms are often used interchangeably), is virtually calorie-free and hundreds of times sweeter than table sugar and naturally so appeals to many people as a natural alternative to artificial sweeteners. While Japanese manufacturers have used stevia since the early 1970s to sweeten pickles and other foods, the FDA has turned down three industry requests to use stevia in foods in the U.S due to the lack of date to conclude that the use [in food] would be safe. Canada doesn’t allow food companies to add stevia to their products. Nor does the European Union
The herb has been consumed without apparent harm in different parts of the world for many years, they argue. No reports of any adverse reactions have surfaced after 30 years of use in Japan.
Growing Stevia: It would be difficult, at best, to start a stevia patch from scratch — that is, by planting seeds. Even if you could get them to germinate, results might well prove disappointing, since stevioside levels can vary greatly in plants grown from seed.
The recommended method is rather to buy garden-ready ‘starter’ plants. Keep in mind that not all stevia plants are created equal in terms of stevioside content, and, hence, sweetness. It’s therefore a good idea to try to determine if the plants you’re buying have been grown from cuttings whose source was high in stevioside.
Once you begin, it’s best to plant your stevia in rows 20 to 24 inches apart, leaving about 18 inches between plants. Your plants should grow to a height of about 30 inches and a width of 18 to 24 inches.
Stevia plants do best in a rich, loamy soil — the same kind in which common garden-variety plants thrive. Since the feeder roots tend to be quite near the surface, it is a good idea to add compost for extra nutrients if the soil in your area is sandy. Take care not to overwater them and to make sure the soil in which they are planted drains easily and isn’t soggy or subject to flooding or puddling.
Frequent light watering is recommended during the summer months. Adding a layer of compost or your favorite mulch around each stevia plant will help keep the shallow feeder roots from drying out.
Stevia plants respond well to fertilizers with lower nitrogen content than the fertilizer’s phosphoric acid or potash content. Most organic fertilizers would work well, since they release nitrogen slowly.
Organic gardeners in particular should find stevia an ideal addition to their yield. Though nontoxic, stevia plants have been found to have insect-repelling tendencies. Their very sweetness, in fact, may be a kind of natural defense mechanism against aphids and other bugs that find it not to their taste. Perhaps that’s why crop-devouring grasshoppers have been reported to bypass stevia under cultivation.
Harvesting Stevia: Harvesting should be done as late as possible, since cool autumn temperatures and shorter days tend to intensify the sweetness of the plants as they evolve into a reproductive state. While exposure to frost is still to be avoided, covering the plants during an early frost can give you the benefit of another few weeks’ growth and more sweetness.
When the time does come to harvest your stevia, the easiest technique is to cut the branches off with pruning shears before stripping the leaves. As an extra bonus, you might also want to clip off the very tips of the stems and add them to your harvest, as they are apt to contain as much stevioside as do the leaves. In that case, your most successful harvest will probably come in the second year. Three-year-old plants will not be as productive and, ideally, should be replaced with new cuttings.
In harsher climates, however, it might be a good idea to take cuttings that will form the basis for the next year’s crop. Cuttings need to be rooted before planting, using either commercial rooting hormones or a natural base made from willow tree tips, pulverized onto a slurry in your blender. After dipping the cuttings in such a preparation, they should be planted in a rooting medium for two to three weeks, giving the new root system a chance to form. They should then be potted — preferably in 4.5-inch pots — and placed in the sunniest and least drafty part of your home until the following spring.
Drying stevia: Once all your leaves have been harvested you will need to dry them. This can be accomplished on a screen or net. The drying process is not one that requires excessive heat; more important is good air circulation. On a moderately warm fall day, your stevia crop can be quick dried in the full sun in about 12 hours. (Drying times longer than that will lower the stevioside content of the final product.) A home dehydrator can also be used, although sun drying is the preferred method.
Crushing the dried leaves is the final step in releasing stevia’s sweetening power. This can be done either by hand or, for greater effect, in a coffee grinder or in a special blender for herbs. You can also make your own liquid stevia extract by adding a cup of warm water to 1/4 cup of fresh, finely-crushed stevia leaves. This mixture should set for 24 hours and then be refrigerated.
You can grow stevia either in pots on your balcony or any sunny spot, or else in a hydroponic unit. Stevia plants also do quite well in “container gardens.” A 10″ to 12″ diameter container filled with a lightweight growing mix is an ideal size for each plant. A little mulch on the top will help retain the moisture in the shallow root zone. A properly fertilised hydroponic unit or container garden can provide you with as much stevia as an outdoor garden, if not more.
Stevia plants ara available at Rs 2 a sapling in several nurseries in Pune. An acre will need around 4,500 saplings.