Growing Kanna from seed.
An instructional supplement for my Etsy store: Noteworthy Plants
As well as for anyone with a desire to grow a variety of mesemb species!
About Kanna: Kanna, or Sceletium tortuosum, is a succulent plant native to South Africa. Kanna is in the Mesembryanthemoideae (Mesemb for short) subfamily, which is the same subfamily as lithops and other split rock species. Like lithops, Kanna is an excellent ornamental species. Kanna is also grown for medicinal and recreational purposes. Unfortunately it can be difficult to grow, but given the right conditions it can thrive on a windowsill indoors. Kanna is grown similarly to lithops and other succulents and cacti, but has its own set of unique challenges. Kanna has beautiful textured shimmering succulent leaves, and produces a plethora of yellow blooms during its flowering period.
Delosperma cooperi, the "Ice Plant", is a close relative of Kanna, also in the mesemb subfamily, and has some interesting properties in its own right. I prefer not to use the name, "ice plant" because there are a large number of other plants with the same name D. cooperi looks similar to, and is in the same family (Aizoaceae) as, the highly sought after "bunny ears" plant (Monilaria moniliformis). Both of which are attractive ornamental plants. The ice plant, as well has the bunny ears plant, has long slender leaves, with a really interesting texture. Two other notable members that I like is Antimima fenestrata and Delosperma nakurense. All of these species mentioned can be grown using the methods described below for Kanna, and there are seeds available in my Etsy store, Noteworthy Plants.
Kanna can be tough to grow. It is best to start with good seeds. I have seeds available in my Etsy store, Noteworthy Plants. I only sell seeds that in my hands have at least a 70% germination rate, using the methods below.
Seasonal Growth Cycle: Kanna appears to only grow for ~3-5 months out of the year, and is dormant for the other 9-7 months. During the dormant months, avoid fertilizing, or watering too much. The soil should stay mostly dry. The leaves may curl up and turn crispy, but during the summer to early fall, Kanna will awake from its dormancy and will grow quickly. New branches, leaves, and towards the end of the cycle, flowers. During this active growth period, it is necessary to provide sufficient water and nutrients. I use a low strength fish emulsion dilution and fertilize every ~2-4 weeks during these active months.
This growth cycle phenomenon is where Kanna gets its genus name from. Sceletium is derived from the Latin word Sceletus, meaning skeleton. This is in reference to the leaves dying back in winter and leaving nothing but a skeleton of branches behind.
I have recently noticed that germination is much lower during winter months. For best results, germinate in Spring - early Fall.
Seed starting tray: Amazon has nice and relatively inexpensive seed starting trays. I get the one with the white bottom and clear top, with a black 12 cell insert. The humidity dome is crucial.
An alternative would be the bag method, which is to plant in whatever pot you desire or have (I would start off with a relatively shallow pot, you only need a 2-4 inches of soil during this first phase) and place it into a clear plastic zip lock bag when you are finished planting. Finally, you can use a deeper pot, and leave some room between the top of the soil and the top of the pot (room for the kanna seedlings to grow), and cover with saran wrap. Again, the common theme to all of these is relatively shallow pot with a humidity dome.
Soil: Look on this website for the soil recipes section. It has some great tips to make aseptic seed starting soil to maximize your success. I recommend the using the seed starting soil as described. Just scoop it from the zip lock bag after it has steamed and cooled down into your pots. Pat the surface down gently so that the soil is relatively compacted and flat on the surface.
Optional: you can use a thin layer of pure coco coir, or coco coir seed starting mix, on the very top. Only 2-3mm thick, enough to surround the seeds and keep them moist.
To plant the seeds: I recommend following the instructions on this website, under “small seedling handling techniques” section, where it goes into the following steps in detail. Carefully empty the tube of seeds onto a clean static free surface (like a fresh sheet of printer paper). You can use regular round toothpicks, dip them in water, and use that moist tip to touch and pick up the individual seeds. If using the 12-well humidity chamber, I would recommend around 4 seeds per cell. Or if planting in one larger pot, leave 1-2 cm between individual seeds.
Once all the seeds are place, I carefully sprinkle on a layer of medium grade sand. I use a salt shaker for this purpose, and my sand has been sterilized. But some good clean fresh sand would work fine. Sprinkle a very fine layer, not so much that you can no longer see the dark organic soil.
Finally, spray thoroughly with water from a spray bottle, until everything is dripping wet. Place on the humidity dome, or into the plastic bag, and place on a windowsill, preferably south facing. East and west facing will work, but just don’t grow under a north facing window (there will be no sun). I keep the seeds warm, or at least room temperature (72F).
Alternative notes: Just like there are as many recipes for tomato sauce as there are cooks in a kitchen there is a wide variety of opinions on Kanna growing from different growers.
Internet lore states that there are water soluble germination inhibitors in kanna seeds. To overcome this hurdle, people have had success by soaking the seeds in a small cup of water, and change out the water every day. I would recommend using either bottled spring water, or dechlorinated boiled tap water for this, as the chorine in the water can perturb all sorts of sensitive biological processes. After a week or so, the seeds should start to germinate in the water, and you can then plant the in soil.
Seedlings: After a few months and the plants start to look sturdier (like on the image below), and are on their 3rd or 4th set of leaves, you can start to remove the humidity chamber for at first hours, and then longer and longer times until you can keep it off. You may still need to mist for some time after the humidity dome. At some point, the root system will grow enough so that it doesn’t need any misting, and you will be able to water it like normal. There is usually a period about a month after germination where aboveground growth slows down. I think it is working on root at this point, so just keep them happy, and they will resume above ground growth after some time.
Mature Plant: When it is a couple of inches tall, I would start with some light cactus fertilizer. Dilute whatever cactus fertilizer you have by 4, and use that on it maybe twice a month. Look out for signs of over or underwatering, or any sort of nutrient stresses. Your kanna plant will grow fast once it reaches the size of your hand, at which point you can fertilize more as tolerated.
Propagation: Kanna will begin flowering at this time. Kanna can be a prolific flowerer, as seen in the image above. Kanna is not self-fertile, so you need at least two simultaneously flowering plants to use pollen from one flower to pollinate the other. This can be done with a fine and soft pain brush. Kanna can also be easily propagated by cuttings. Use a piece of stem 2-3 inches long, let a callus form over a couple of days, and place it in some cactus soil and keep moist.
Have fun and enjoy!