For several years, I stratified seeds in the fridge : 50% 2-3 mm aquarium sand + 50% sphagnum moss, or peat. I even tried what was suggested on a bonsai forum : soaking the seeds for 24-48 hours, discarding those that float, filter them and just put them in a zip bag without any medium. I had lots of seeds 2 years ago, I tried it, and it worked ! Just make sure the seeds are damp, but not soaked, and open the bag once in a while. I also sowed some in planters, or various pots and containers, left them outside and actually this seems the best option : less hassle and an equivalent success. In this case, I use 25% sand and the rest is a mix of what I have at hand (growing medium, akadama, ...) I also use a little hydrogen peroxide when soaking them, it's to prevent diseases. That's what my Mum used when I get back home crying, with a bleeding knee, so that must be good ;°) On some online vending sites, I saw that some species like shirasawanum and others are supposed to have a "double stratification" : 2 or 3 months warm stratif (20° or so), then 3-4 months cold stratif (3-5°C) Since I think that altenate periods of cold and waemer weather helps, I'm trying a "shortcut" : 3 weeks indoors, next to a radiator (20-22°), then 3 weeks in the fridge, then 3 weeks indoors, 3 weeks in the fridge again, then I will plant them in a planter and leave them outside. I tried it once, but I didn't have many seeds : only 3 out of 10 or so germinated, but that's not so bad, is it ?
Wait, isn't it the other way around, those that float are empty? Our own D (@LoverOfMaples) wrote a really good article for the MS JM FAQ, on how to grow seeds, several people have already found it really helpful. He doesn't use medium in the bags. For the double stratification, I find the first year in the fridge and a second winter outside, I get germination on the second year often. It will be interesting to see if your system works! I use the fridge the first winter 'cause of mice. -E
Damn! All they say on French forums is wrong then ? Well, all the seeds that were sunk were flat, and those floating were rounded, so...
Curious from you, my dear ! Don’t you understand french ? All those that float are empty (you have to move samares in water and wait one or two days to be sure to chose the good one’s, they are down water). As Emery suggest, i am pretty sure of that and say it on a french forum since years.
It would be interesting to see if all of @AlainK's floaters (now stratifying) are indeed empty. If he wishes, he could cut a sample of his floaters in half to see, rather than wait many months to find out.
Hey yall! In my experience, the floating ones are empty. I normally let them soak for an extra 24hr after the first 24 to make sure. When I first started germinating seeds I decided to check some of the floaters to see what was inside. I found some were either empty and some had developed looking ones. I throw the floaters out in the flower beds. But I did keep about 500+ floaters from Acer shirasawanum 'Palmatifidium' this year to see if i have any luck.
I'll get some more seeds from a friend, I hope that I will do it right this time. To illustrate what I do when I plant seeds, this time without soaking them, so I can't be wrong! - Oh my, what a shame... I put a piece of "plastic corrugated cardboad", or whatever you call it, to show the size of the pozzolan. 1-1.5 cm: 0.5-0.7cm Mix : 10% pozzolan 5-7, 60% potting soil, 30% 2-3 mm aqurarium sand: Adding seeds on a fine layer with a bit more sand: I try to plant seeds that are different so if ever the labels get lost, the seedlings will look different.
At the last minute decided to pick seeds for sowing today, at least partially inspired by this thread! Still quite a few were in evidence on the most heavily seeded trees despite the lateness of season. They are going to be soaked overnight and planted out tomorrow. I like to stratify outdoors, the natural way, and am fortunate not to be be bothered by rodents so can feel safe with the seeds outdoors all winter. Not soaking to separate floaters, just to be sure the seeds are sufficiently hydrated. I will plant them all and any empty ones will add organic matter to benefit the fertile ones. Off topic a little but interesting to note the difference in size between Acer palmatum and Acer amoenum var. matsumurae. Top to bottom: 'Azuma murasaki' (said to be matsumurae) ; 'Senkaki' or 'Sango kaku' (palmatum) ; dissectum (matsumurae) :
Well, after 16 hours at 15-16 degrees C most had sunk anyway. (80-90% for the larger varieties and 99% for the 'Senkaki') I had already discarded all the obviously empty ones at the picking stage. They are now potted and living outside for the winter. These were rather aged seeds; not sure if fresh "in the green" or "in the red" seeds would behave the same way as they don't have the dried tissue ready to soak up the water. A few months ago I planted out some old Acer shirasawanum 'Aureum' and Acer X 'Jordan' seeds I found that had been living in the back of the fridge for an unknown number of years. Will be interesting to see if (m)any sprout next spring.
I tried 3 things this year, all with fresh seed 1) 50/50 sand/peat mix, put in seed, moisten a bit, spray with fungicide, and put in fridge 2) put seed in bag, moisten a bit, spray with fungicide, and put in fridge 3) regular sowing mix, put in seed, water well, put in greenhouse for the winter Let's see what happens... Been reading a Dutch professional article about stratification of acer palmatum spp. palmatum seed (75.000 seed per kg), this is the small seed, which don't need a warm period before the cold period. You should add about 35 to 37% water to your seed and store at 1-5 °C. 39% or more will cause early germination. Weigh every week and keep moisture at 35-37%. After 12 weeks, sow outside. Results were amazing compared to "the old way" of sowing outside.
