This is the process to which I referred in last Saturday's post, the one that got me ~91% germination on a batch of gift seeds. (This is the last day to request your own Clivia seeds.) It works a lot better than the process I used on my Clivia seeds in 2013.
You will need: ripe Clivia fruits, a germination container, vermiculite, vinegar, a pot in which to boil water, a bowl, paper towels, a warm but not hot surface on which to set your container.
(EDITED to add photos, 4 May 2017)
1. Get ripe fruit that contains seeds. I'm not actually super clear on how you know when a fruit is ripe, but I figured it out in 2013 so I'm going to assume it's pretty obvious.
2. Boil some water. (Tap water is fine; softened tap water is not.) This is mostly for your germination medium, so how much water you need depends on how many seeds you're starting, but, you know, it's just water, and it's about as easy to boil a lot as it is to boil a little. Once that's done, cover it, set it aside to cool, and hope that it will be cooled down enough to use by the time you get to step 6.
3. Open the fruit. I just kind of squeeze it until it comes open; this is kind of messy, but not as messy as you'd think, since almost the entire volume of the fruits is dedicated to seeds, so there's very little pulp.1
4. There is a thin membrane or skin covering each of the seeds individually, which will likely tear as you separate the seeds from one another. You need to remove all of the membrane from the seeds. It's fairly easy to see and feel the difference between covered and uncovered seeds, as the membrane is a little bit fibrous, and thick enough to be visible. It also peels off of about 80% of the seeds really easily, and is impossible to get off of the remaining 20% because the whole thing is kind of wet and slimy and the seed itself is round so there's no easy way to get a tear started. (I had some success with setting down a paper towel on the work surface and rubbing one particular spot on the seed lightly against the paper towel until a hole started.)
This is the most annoying step of the process; it's all downhill from here.
5. Next you'll need to get a container to start the seeds in, and a growing medium. I used vermiculite for my growing medium, and strongly recommend that you do too.2 For a container, I used the same clear plastic containers I use for germinating everything else,
but there's a lot of leeway there. Mostly what you need is a container that allows light in, but not air (or at least, not a lot of air -- you don't want the seeds to dry out), and is deep enough to accommodate 1-1.5 inches of vermiculite at the bottom while still leaving a couple inches of room for leaves to grow.
6. You need to moisten the vermiculite. If your boiled water has cooled off to 90F/32C or below, go ahead and saturate the vermiculite. (90F/32C is a guess; I'm pretty confident it's safe, but that doesn't mean 95F/35C is necessarily not.) Pour off any excess water, then cover the container.
7. Rinse the seeds in dilute white vinegar. I was told 2% vinegar, but I didn't actually measure it out when I did it: I just filled a clean large bowl with water, added a couple splashes of the vinegar, and dropped the seeds in.3
8. Pour the vinegar solution off the seeds, rinse with more of the boiled water and pour that off too, then set the seeds in the vermiculite, eyes down. (The eye is a slightly-raised bump on the seeds; it's easy to locate because it's the only distinguishable feature they have.4)
9. Cover/close the container and set it in a location with bottom heat (on top of a refrigerator or hot water heater; maybe on a heat mat specifically for seed germination if you're fancy5) and wait.
I saw the first leaves and roots begin to appear after about two weeks. They won't necessarily all germinate at once. Some small percentage are likely to be duds, that do nothing at all (about 6% of the total, in my case), and a few others germinate but then just stop developing (about 3%). Since so many did work, I didn't bother trying to figure out what was wrong with the ones that didn't.
10. Seedlings are ready to transplant to individual pots of potting soil (about 2-3" diameter) when the roots are about an inch long. Usually you see the surface of the seed shrivel and dull a little, too.
It's fairly obvious where the soil level should be: the plant starts growing out of the side of the seed, with leaves going one direction and the root going another. Plant it so that the root is below the soil and the leaf is above the soil. The seed will usually wind up mostly above the soil.
My source recommends a mixture of orchid bark, perlite, and a little bit of time-release fertilizer like Osmocote, though I didn't follow most of those suggestions6 and my seedlings seem to be fine.7
11. I set my potted seedlings on a low shelf in the living room (which means strong air movement, cool temperatures, and brief morning sun) but I don't think they're super-picky about location. I do watch them pretty closely to see whether the soil is drying out, and so far have been watering them about once a week; if we didn't have the ceiling fan going, I could probably get away with less frequent watering.
And that's pretty much it. The tricky part, for me, is getting Clivias to bloom: they need cooler temperatures than we have in the house. I may try keeping some of them outside this year so they're properly chilled.
This is not the only process that people have gotten to work; my source reports being able to start them in damp paper towels sometimes, and that some people soak them in water until they germinate though that doesn't seem to work as well. A few people just plant the whole fruit in potting soil without doing anything else, and apparently get seedlings out of that sometimes. My source says that on at least one occasion, she didn't have time to sow the seeds after stripping the membrane off of them, so she put them in the bottom drawer of a refrigerator, in perlite, and forgot about them, and a substantial percentage of those germinated when she checked them later. But I can vouch for the method outlined above, not the others, so it's what I'm recommending.
2 I've tried perlite and potting soil previously. Perlite doesn't seem to work for me, though some people apparently can use it successfully. They'll germinate in potting soil, but the main obstacle to germination is fungus, so things work out a whole lot better if you use a sterile medium like vermiculite.
3 I'm told it doesn't necessarily hurt anything to rinse the container out with some of the vinegar solution, followed by boiled water, at the beginning of step 5, but I was pretty confident that my container was clean already, so I didn't bother.
4 I'm not convinced that the direction of planting makes that much difference, personally, since the roots are bad at burrowing into the vermiculite. What winds up happening is that the seed scoots around on the surface of the vermiculite, or turns itself upside down, or whatever, as the root tries to grow downward but can't penetrate the surface of the vermiculite. I include it anyway because it was in the instructions I got, and I'm not sure it doesn't make a difference, either.
5 The light fixtures on the shelving units in the basement are warm enough that I just set my Clivia seeds on the shelves and let the light for the shelf below them provide the heat.
6 The roots were 2 or 3 inches long on most of the plants. (I potted them up on 30 March, about 7 weeks after sowing; some of them were probably ready to go after 4 weeks. Compared to Anthurium and Schlumbergera, Clivia seedlings grow very quickly.)
I did use 2.5" pots, but I used my regular potting mix (about 45% composted bark and 40% chopped sphagnum moss), and I fertilize with the Miracle Gro I use on my other plants.
7 I did lose a few. A couple were, I think, late germinators that weren't developed enough to pot up yet. I broke the tip off the root of one of them, which either set it back or killed it. (I'm not sure which one of them it is.) A couple got knocked out of place when I watered, buried under the potting soil, and may or may not be able to grow enough to dig themselves out. I'm still going to end up with about 60-65 seedlings, from an initial 77.