We hope so, because we’ve got fresh, top-quality stevia seed just waiting for your garden and container! As more and more of us transition from sugar or artificial sweeteners to the natural goodness of Stevia rebaudiana, it makes sense to integrate this plant into our gardens. Here’s how:
Native to the tropical climates of South America, stevia is found along stream banks and in rich forest floors in the wild. Technically it is a tender perennial, but unless you live in zones 10 or 11, you will be growing it as an annual. (The easiest and most effective way to harvest stevia is to cut the entire plant, anyway!) It needs three things: full sunshine (or very bright light if you want to grow it indoors), consistent moisture, and excellent soil drainage. Given these, it grows readily.
Starting stevia from seed
is not like tossing out some zinnia or bean seeds into the spring soil, but it isn’t really difficult. If you have a Bio Dome and plant grow lights, it’s a snap. Let’s look at that process first:
Drop one seed into each pre-drilled hole of the Bio Dome, put the cover on the dome, and set it beneath grow lights in a room with a temperature of 70 to 75 degrees F. (Actually, it can be a little cooler, because the dome will add a few degrees.) If your room is too cool, use a heat mat beneath the dome. Within 1 to 2 weeks, you will see sprouts. Do not be discouraged if they do not roar right up in size; stevia grows slowly, but it is not fussy. Bottom-water the dome and add seedling fertilizer; the little sprouts will reach transplant size within 8 weeks of sowing.
If you are starting the seeds in a seed flat, egg carton, or other container, place 3 to 4 seeds together in very shallow holes, or sow lines of closely-spaced seeds in rows about rows about 4 inches apart. Cover the holes or rows with a scant 1/8-inch vermiculite, and water from the bottom of the tray or mist very lightly from the top. Keep room temperature at 70 to 75 degrees F, or use a heat mat beneath the seed flat. If you do not have grow lights, place the flat in a bright (but not drafty) windowsill or just below kitchen fluorescents. Germination should take 7 to 15 days. When the seedlings are an inch or two high, thin them, discarding or transplanting the extras.
If you are growing stevia for the garden, sow the seeds at least 8 weeks before the last scheduled frost in your area. (For indoor use, of course, they can be started at any time of year.) Wait until the soil has warmed and nights are consistently above 55 degrees F before transplanting this tropical.
In the garden, you can grow stevia in any sunny spot.
To ensure excellent drainage, raised beds are superb, but so is hilling up a mount of soil and planting it there, a few inches above the soil line. The soil should be enriched, but don’t bombard it with fertilizer throughout the growing season; that will affect the flavor of the leaves. Just begin with good garden soil, mulch around the plant when the summer heat arrives (to keep moisture in), and watch it closely for signs of budding.
Stevia reaches its peak of flavor just as it begins to flower. Now, you can pick individual leaves for eating all season long, beginning just a few weeks after you transplant the seedlings. Like most herbs, it will regrow any cut stems, and so you will get a bigger harvest by cut-and-come-again picking. But the intensity of the sweetness doesn’t reach its peak until you see flower buds. Experiment with harvesting both ways and see which you like!
Flowering is triggered in stevia by cold temperatures. These may occur in late summer, early fall, even late fall if you have an Indian summer. Just keep an eye on the weather (as gardeners, do we ever do anything else?!), and when the chilly mornings arrive and you see buds on your stevia plants, cut the whole plant, hang it upside down in a warm, dry place, and once it has become brittle, strip the leaves with a simple swipe of your hand. Done! Your harvest is ready!
In the garden, stevia can reach a foot high and about a foot and a half wide. If it’s in a container, it will probably stay smaller. If you want to let a few plants flower so that you can collect their seed for next season, go ahead; this is the species and will come true from seed. (And wouldn’t it be fun to grow a bunch of little seedlings to give as “sweet treats” to friends for the holidays?) Have fun discovering the various ways you can grow and enjoy your stevia plants. We’re so glad to have this new herb brightening our gardens and satisfying our sweet tooth!