How to Grow Stevia

• Introduction
• How to Start Your Own Stevia Patch
• The Care and Feeding of Stevia
• Gathering autumn stevia leaves
• Unlocking the sweetness in your harvest
• Growing stevia without land
• Sources for mail-order stevia plants

Introduction

You need not be a South American planter to be a successful stevia grower. While the herb’s native locale may make it appear somewhat exotic, it has proved to be quite adaptable and capable of being cultivated in climate zones as diverse as Florida and southern Canada.

True, home-grown stevia may lack the potency of refined white stevia extract; whole stevioside content generally ranges from 81 to 91 percent, as compared to a leaf level of approximately 12 percent. But it can provide you with a quantity of freshly harvested stevia ‘tea leaves’ to augment your supply of commercial stevia sweeteners.

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.

Then, too, raising stevia yourself, whether in your back yard or on your balcony, is another positive way you can personally (and quite legally) protest the wrongheaded government policies that have for so long deprived the American people of its benefits — a kind of contemporary Victory Garden.

How to Start Your Own Stevia Patch

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, which given stevia’s ‘growing’ popularity, may well be obtainable from a nursery or herbalist in your area — provided you’re willing to scout around a bit. If you’re not, or are unsuccessful in locating any, there are at least three growers of high-quality stevia who will ship you as many baby plants as you’d like.

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.

Because tender young stevia plants are especially sensitive to low temperatures, it’s important that you wait until the danger of frost is past and soil temperatures are well into the 50s and 60s before transplanting them into your garden.

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.

The Care and Feeding of Stevia

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.

Besides being sensitive to cold during their developmental stage, the roots can also be adversely affected by excessive levels of moisture. So 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 a lower nitrogen content than the fertilizer’s phosphoric acid or potash content. Most organic fertilizers would work well, since they release nitrogen slowly.

Gathering Autumn Stevia Leaves

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.

If you live in a relatively frost-free climate, your plants may well be able to survive the winter outside, provided you do not cut the branches too short (leaving about 4 inches of stem at the base during pruning). 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.

Unlocking the Sweetness in Your Harvest

Once all your leaves have been harvested you will need to dry them. This can be accomplished on a screen or net. (For a larger application, an alfalfa or grain drier can be used, but about the only way an average gardener might gain access to such a device is to borrow it from a friendly neighborhood farmer). 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.

Growing Stevia Without Land

Just because you live within the confines of an apartment or condominium doesn’t mean you can’t enjoy the benefits of stevia farming. This versatile plant can be grown 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 fertilized hydroponic unit or container garden can provide you with as much stevia as an outdoor garden, if not more.

Sources for mail-order stevia plants

The Herbal Advantage is a Missouri herb supplier offering 2 1/4″ pot size stevia plants ready for planting in your garden. For information and prices, call 800-753-9929, or write to them at Rte. 3, Box 93, Rogersville, MO 65742

Richter’s Herbs, a Canadian business, offers plants in 2 1/2″ pots via courier to customers in the U.S. and Canada. For information and prices, you can call (905) 640-6677 or fax them at (905) 640-6641 or write them at 357 Highway 47, Goodwood, Ontario L0C-1A0

Well Sweep Herb Farm is another source offering plants in 3″ pots either via mail order or to customers who stop by. It is located at 205 Mt. Bethel Road, Port Murray, NJ 07865 or can be reached at (908) 852-5390

Reprinted from The Stevia Story, copyright 1997 by Donna Gates. Photos courtesy Agriculture Canada.