Grow Your Own Stevia (S. rebaudiana)

When most people think of ‘Stevia’, they think of the powdered green (or white… if it’s been bleached) stuff you can buy from most supermarkets, for use as an alternative sweetener.  But it doesn’t start out that way.

Stevia is a herb that you can grow in your garden.

I get a lot of questions about stevia, so I thought I’d give you a quick brief on it, including my experience in growing it the last several years.

Stevia is actually a whole group of plants in the Asteraceae (daisy) family.  The single plant prized for its sweet leaves is Stevia rebaudiana (so be sure that’s what you’re getting when you’re purchasing seeds).  Some say that growing from seed won’t produce a sweet plant, or that you’re less likely to get a sweet plant.

But let me debunk that myth right now. Stevia grown from seed is just as sweet as any other Stevia rebaudiana plant you might purchase.

This claim is likely a marketing gimmick, put out by the people who will profit a lot more when you purchase plants, instead of a packet of seeds.

In fact, I prefer to grow stevia from seed.

We’ve moved a handful of times, and usually I haven’t been able to take my plants with me (cross-country moves are hard on plants… and there are a couple of states in the U.S. that don’t allow you to take your plants across the border). So I’ve had to restart my stevia more than once.

When you grow stevia from seed, it’s true that the plants will vary slightly in the chemical makeup of the leaves. Some will be sweeter, and some will be less sweet. Some will have a fairly strong aftertaste (which some people really don’t like) and others will have hardly any aftertaste at all.

When you grow stevia plants from seed, you can grow lots of different plants, pick the plant(s) that produce the sweetest leaves with the least amount of aftertaste, and propagate from those with cuttings.

It’s ideal – least expensive method and you get the plants that suit you best. Perhaps not ideal for nurseries trying to sell you stevia plants, but that’s hardly your concern.

The only caveat is that stevia can be slightly ‘difficult’ to start from seed – and by difficult, I mean temperamental. Sometimes the seeds sprout beautifully, and sometimes they take forever to sprout, and then only half of them do. And the seedlings need to be coddled a little bit, for the first few weeks.

Once it’s growing, though, it grows very well.  It’s a pretty sturdy plant once it’s become established.  It produces fairly thick, leafy stalks. It’s best to keep it lower and bushier by pinching it back every few weeks.

If you just let it grow and reach its full height, it’ll begin to put out flower heads once the stalk reaches 2-3 feet tall.  The leaves become very sweet as the flower heads begin to appear (but before the flowers fully develop and open), and that’s just about the time you want to cut the stalks and dry the leaves.

Cut the stalk about 6 inches above the ground, right above a set of leaves.  The plant will sprout two new stems right above each of the leaves (as you can see in the picture at the bottom right).  These stalks were cut about a week earlier, and already you can see the growth of two new stems right above each of the leaves.

I found that S. rebaudiana likes a good dose of water nearly every day (and sometimes twice a day when it gets hot, especially if it’s in a container), but the container/soil needs to drain very well so it’s not standing in water, and has enough time to dry in between waterings.  I used sifted compost and sand to create a good, healthy mix for my stevia, and it worked very well.  If stevia gets too wet or the roots sit in water too often or too long, it can be affected by fungal disease, so good drainage is a must.

New shoots beginning to grow out of the leaf nodes on either side of the cut stalk.

I wanted to use compost, because a stevia plant that is fed with a nitrogen fertilizer will keep the leaves green, and perhaps produce more leaves, but they won’t be as sweet, and sweetness was my goal.  So to keep the plant healthy, with plenty of nutrients, without compromising the sweetness, a well-composted compost seemed to be the best option and it worked well with a good dose of sand mixed in (for my potted stevia.  A common garden fertilizer without nitrogen (or a minimal amount) would probably work well, too.

On the last note of nutrients – I have heard that fertilizing your stevia plant with Boron will increase its sweetness (perhaps boron is part of the process of making the sweetener that stevia plants produce) but I haven’t verified that claim.

A lot of people as me how stevia compares to sugar, and the truth is… it’s actually sweeter!  The sweetness comes from two chemicals: Rebaudioside A and stevioside.  As far as we know, it’s the stevioside that leaves a *slightly* bitter aftertaste.

There is a new ‘North American Stevia’ plant, which has been developed, through cross-pollination and selection, to contain less of the stevioside and more of the Rebaudioside A, so you supposedly don’t get very much of the bitter aftertaste.

The packet of seeds I grew did not indicate that it was one of these or not, so I don’t know which one I have.  The leaves on my plant are definitely sweet, and I don’t taste much of a ‘bitter’ aftertaste, though it is certainly a different sweetness from sugar… and maybe an ‘off’ aftertaste lingers a bit on the tongue.  If you want to be sure to get the new North American Stevia plant, it would probably be best to purchase one as a seedling, since cuttings are guaranteed to be true to the mother plant.  Check your local nursery for seedlings, or you can order seeds online from several different sources, including Baker Creek and Seed Savers.

The stevia stalks grew tall and strong, but they were a bit brittle, so I took care to stake them, and I’m glad I did.  The tallest stalk had the top snapped cleanly off during a very windy storm over the summer… the one bit that I hadn’t supported with some stakes and rope, so I was glad I’d supported the rest of the plant. You can also pinch it back regularly so it doesn’t get more then 6-12 inches tall, but I let mine grow tall in the beginning because I wanted to make sure it established well… having been so finicky to start from seed.

Grow your stevia in full sunlight.  The more sun, the more the plant will produce the sweetness in the plant, and the healthier the plant will be.

I’ll be overwintering my inside, which is why I grew it in a pot, because it is a very tender perennial.  If you grow it in the ground, you can either lift it and pot it up to bring it inside for the winter (if you’re colder than zone 9), or you can harvest it the stalks and let the plant die, and then just grow it again the next year.  If you overwinter it inside, be on the lookout for white fly.  If your plant is being attacked by whitefly, spray the plant with a Insecticidal soap, or a dilute mixture of water and household dish soap (making sure it doesn’t have perfumes or other chemicals in it that may harm your plant).  Or you can make a sticky trap with contact paper and a small stake.

The seeds are fairly expensive, as far as seeds go.  Once you’ve got an established plant, you can propagate it with stem cuttings, which are more likely to be successful if you use a rooting hormone powder.  I’ll be trying that myself in a few days, so I’ll give you an updated post to let you know how it goes.

To use stevia in cooking, once you’ve harvested the stalks, hang them upside down to dry until the leaves are brittle.  Or you can pull the leaves off the stem immediately and spread them out to dry on a screen.  Once they’re brittle, you can pull them off the stem and store them in an airtight container, or you can powder them (either manually or with a food processor) before storing them.

Then, when cooking, add a measured amount of the stevia powder to recipes.  Remember that because stevia powder doesn’t have the same properties as sugar, other ingredients in the recipe may need to be adjusted to retain moisture levels, rising action, etc. to compensate for the decreased amount of sugar.

I found a great Pinterest board with a bunch of recipes using stevia.  I think you’ll find it useful.  I can’t wait to try some of the recipes on there myself.

For my herbal teas, I just add a leaf to stew with the other herbs.  I can use the same leaf at least 2 or 3 times with great results.

I hope you enjoy growing and using stevia!  Below are some pictures of the growth of our stevia plant throughout the summer.  I thought you’d find them interesting.

One Response to Grow Your Own Stevia (S. rebaudiana)

  1. likia April 5, 2017 at 7:35 pm #

    Thank you for your sharing . Great information.
    I also read that boron improve the sweetness,
    maybe because boron is used as sugar translocation in the plant.


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