"Is it okay if I take this apple?" I asked my mother the other day. "I need it for starting seeds."
Being slightly deaf, she gave me a skeptical look, as if doubtful that she'd heard me right. Perhaps she just felt inclined to remind me that apples don't come true from seeds. But it wasn't actually those that I planned to start. I needed a slice of the apple to put in a container with some sand verbena (Abronia) seeds. I'd been informed that ethylene would jumpstart them, so to speak, and ethylene comes from ripening fruit.
The treatment actually worked, as two of the three sand verbena seeds--which I'd placed on a damp paper towel with the apple inside a sealed container--sprouted right away. You should change the pieces of apple frequently, if you try this, as they mold quickly.
Scientists are conducting quite a few experiments these days to see which other seeds might have their sprouting accelerated by the use of ethylene. As it actually reduces germination in some types, though, I wouldn't try it with most of them until we know for sure.
We do know that quite a few species need smoke. Those are generally plants native to dry countries or grasslands where wildfires are common. Smoke cues them that they need to get busy and start replenishing those burned-over areas.
Fortunately, some seed sellers can provide you with papers which have been saturated with a smoke solution and then dried. You only need to add those papers to the water in which you soak your seeds. I've heard that the liquid smoke flavoring you buy at the supermarket will also work.
I would stick to the wet forms of smoke, even though I've seen some people recommend burning dried leaves or pine needles on top of your seed flat. If a klutz like me tried that, I would in short order set fire to the flat, myself, and everything else in the immediate vicinity.
The smoke treatment worked almost too well on some sugarbush (Protea) seeds I purchased a couple years ago, as I'd never had any luck with them before and so had planted too many. Granted, smoke hasn't helped with everything on which I've tried it, but I tend to overwater seed flats--not a good idea for plants accustomed to arid conditions.
The seed treatment I've employed most frequently is gibberellic acid, GA3. It's a plant hormone that, if used in small amounts, encourages sprouting in certain types of hard-to-germinate seeds or some with low germination rates. Gibberellic acid comes in the form of a white powder which is mixed with water.
I've tried it with albuca, vanilla lily (Anthropodium), columbine (Aquilegia), fuchsia, lewisia, lobelia, Matilija poppy (Romneya ) and sweet violet (Viola), all of which germinated. But I've also tried it with Japanese wood poppy (Glaucidium), saxifrage (Saxifraga), meadow rue (Thalictrum), and wake robin (Trillium), none of which germinated. So it's not what you would call a sure thing, and a lot still depends on the freshness and viability of your seeds. The acid can also cause weak and leggy stems in some seedlings. So I would only use it for species that are difficult to start by other means.
If you aren't sure which species those are, do as I do, and consult Norman Deno's books--mentioned in my previous article on starting seeds with paper towels. As for the smoke treatment, it is often recommended for species native to Australia or South Africa.
You may ask why someone who lives in Pennsylvania would want to start species from Australia and South Africa anyway, which is a good question! I must admit that I just enjoy the challenge. While some of those plants can weather our zone 5 winters under my grow-lights, others don't survive for long. But, as they say--and could say about seed germination as well--you never know until you try!
Photos: The Abronia fragrans photo in the thumbnail is by Jerry Friedman, courtesy of Wikimedia Commons and the Protea photo is by autodesign, courtesy of stock.xchng. The other photos are my own.