How To Grow Stevia and Make Your Own Extract

Sugar cane, sugar beets, agave, brown rice, barley, Sugar Maple, sorghum, and stevia, are all plants that can be grown for their sugars. Among these, stevia is the sweetest.  A good quality stevia leaf is estimated to be 300 times sweeter than cane sugar, or sucrose. There is evidence that stevia may even lower blood pressure, prevent and reverse diabetes, and possess anti-viral properties. Refined sugar is virtually devoid of nutritional benefits and, at best, represents empty calories in the diet. At worst, it has been implicated in numerous degenerative diseases. Stevia is much sweeter than sugar and has none of sugar’s unhealthy drawbacks.

There are over 200 species in the genus Stevia.  Native to subtropical and tropical regions of western North America and South America, the species Stevia rebaudiana, is the variety generally cultivated for the sweet leaves (it is one of the least bitter varieties).  Stevia rebaudiana is a small herbaceous shrub, a tender perennial. Wild plants occur on acid soils that are constantly moist, but not inundated, often near the edge of marshes or streams where the soil is sandy (Brandle et al., 1998). Stevia occurs naturally on soils of pH 4 to 5, but thrives with soil pH as high as 7.5. However, Stevia does not tolerate saline soils (Shock, 1982). It can be grown as an annual in cold regions.

Growing from seed: Stevia can be started from seed in late winter or very early spring. In general, stevia should be treated similar to tomatoes when starting from seed.  A standard potting soil mix works fine. Plant 2-3 of the tiny seeds in each pot or cell.  Cover the seeds with only about 1/8 inch of soil or fine vermiculite, and moisten gently with a spray bottle. Place a container or flat under the cells that will hold water.  Fill the bottom flat or container with about 1/4 inch of water, which will allow plenty of moisture to be absorbed. Place a clear cover on next, slightly ajar or with a few small holes punched in, to allow  airflow.  A sunny window or a  grow light and temperatures between 72 and 80 degrees will get the germination going after 6-14 days.

Remove the cover when more than half the pots or cells have seedlings showing. Keep watering the tiny seedlings from the bottom, rather than the top.   The goal is to keep the soil slightly moist, not soggy.  After about the third watering, add a little low nitrogen (1-1-1) fertilizer to the water every other watering (use a natural one, like sea kelp).  When the seedlings begin to grow well, decide which one is the best or strongest out of each pot or cell and cull the others (just cut off the top with scissors).

At about 8 or more weeks after germination, the plants may be transplanted into larger pots or into the ground if it is warm enough. When seedlings reach around 5 inches tall, trim 1-2 inches off the man shoot to promote branching  (you may use these leaves for sweetening.). Harden off plants for at least 5 days before transplanting to the garden. Do this by placing plants outside in a protected area on nice days and bring them in at night when temperatures are forecast to drop  below about 40° F.

Plants can be lifted from the ground and put in pots to bring inside in cold climates.  Once you have a strong, healthy plant going  you can propagate it through cuttings to increase your number of plants.  For a complete guide to propagation through cuttings, visit this great link.

Leaves may be harvested and used at any time after the plant is well established.  For a large single harvest, pick the leaves in late summer or fall as plants are starting to blossom.

Most recipes out there call for dried stevia powder or liquid stevia extract so that the flavor spreads uniformly through the substance being sweetened, but the leaves can also be used fresh. For example whole leaves can be used in tea, they can be pureed (like a pesto) and used in baked goods or sweet breads.

To make a liquid stevia extract (like the ones that sell for over $10 in the store) follow these instructions from Food Renegade:

“If you harvest your stevia at home, begin by washing your cuttings to remove dirt. Remove the leaves from the stem, as the leaves are what contains the sweet-tasting glycosides. Let them dry in the sun or a dehydrator until crisp. Then, using a knife chop your dried stevia leaves finely. Do not powder your leaves as the powder is hard to filter out later and creates a residue that settles at the bottom of your finished extract.

If you don’t have a stevia plant, don’t worry. You can find dried stevia leaves just about anywhere you can buy herbs. (See where to buy stevia here.)

Place your crushed stevia leaves in a glass jar, then pour vodka over them to coat. We are using vodka instead of water to extract the glycosides because we’ll get a much sweeter end result this way. Opt for vodka over other liquors because it’s flavorless and cheap.

Put the lid on your jar, shake it up, and let it sit on your counter for 24-36 hours. Don’t let it sit for longer than 36 hours, as it will turn more bitter. I used to make a liquid stevia extract the same way that I made other herbal tinctures, letting it sit for weeks. While this may improve the medicinal quality of the extract, it sacrificed a lot of sweetness to do it.

Next, filter out the leaves. You can do this by pouring the extract through a coffee filter or cheesecloth.

At this point, you have two options.

1) Keep the alcohol-containing liquid stevia extract. To do this, transfer into a colored glass bottle (for light reduction), and store in a room temperature, dark place for up to 2-4 years.

2) Remove the alcohol from the liquid stevia extract. To do this, gently heat the extract over low-heat for 20-30 minutes. DO NOT BOIL. If your extract comes to a boil, you will overheat the glycosides and destroy the sweet taste. The longer you heat the extract, the thicker and more syrup-like it will become. I’ve found that on my electric stove top on low, 20 minutes is about ideal. Transfer into a colored glass tincture bottle and store in your refrigerator for up to 3 months.”

To make a dried stevia powder (green powder–the white color in the store products is due to it being refined):

Place dried leaves in a blender or food processor and blitz until very fine.  Store in a jar or shaker.

On average, stevia can be substituted for sugar at 1 teaspoon liquid or powdered stevia for 1 cup of sugar.  This link has a conversion chart.

To find locally grown stevia plants or leaves, or any other farm produced items, search!


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