Curious to what your current preferred stratification medium if stratifying in a ziplock baggie? These are the options I am considering, I would love to hear your recent experiences with them:
Paper towel
Perlite
Vermiculite
Pro-mix or other seedling mix
Peat moss
Silica sand
Playground sand
Nothing - moist bag
Are there any other options available?
Any feedback is greatly appreciated!
Thank you,
Roselynn
Hi Roselynn,
I just finished statifying my rose seeds, I used I litre ziploc bags and just a 1/4 cup of pro-mix.
I add only one tablespoon on water to each bag.
Chuckp
Nothing. I shell the seed and put each cross in a small zip loc bag with a plastic label. IF I have to hold them a long time (weeks) prior to planting, they go in the vegetable crisper. If I can plant fairly immediately, I just keep them in the house where it remains in the sixties to low seventies, then plant. They really don’t seem to even notice.
Playground sand.
It does not support mold.
It can be separated from the germinating seeds with a kitchen strainer and running water.
The color of the sand changes when dry.
It does not react with germination enhancers like digestive enzymes and hydrogen peroxide.
Usually I have sown my seeds directly into a seedling flat with a commercial germination mix, as I have the luxury of a cold storage facility that can fit many flats. Last year I decided to do that but give them a warm stratification period as some have recommended. It didn’t seem to work out so well. It seemed like germination percentages were quite low, although I don’t have hard data. So this year I’m going to try stratifying them in the baggies with nothing else added. I figure I’ll dip them in a calcium nitrate solution, give the strainer a few taps, and dump them in the bag. I am also going to experiment with a bleach soak prior to stratification as was outlined in the paper that was linked to here fairly recently. I haven’t decided how much if any warm stratification to give them prior to the cold. I really don’t want them germinating in the baggies, so I am going to try to find a fridge space that stays just above freezing. Then later in the winter I will sow them. I, too, welcome any tips or suggestions from those more experienced.
What Henry Kuska said about playground sand is true, but I did experience some mold. Here, cleaned masonry silica sand is what is used as playground sand, if that made any difference. I now use perlite for several reasons-lite weight, easy to see the seedling root emerge, and because it is lite weight, it is easier to remove a fragile root that might get otherwise missed without breakage. I moisten it with the calcium nitrate solution closely following the recommended dosage per gal of water and cold stratify. Except for last yr (had the house fumigated-seems to have affected germination) germination has been good.
I like using a higher quality peat moss in baggies. It makes it easier for me to see the white roots emerge against the dark peat and it seems to have some natural antifungal properties. If I transplant relatively early, the roots separate pretty easily.
Moist vermiculite in 2 oz plastic cups in plastic bags.
Just a light mist of water in plastic bags for the last 2 years and germinations seem unchanged.
This sounds interesting and a lot less work. I think I’ll give this a try this winter.
This sounds interesting and a lot less work. I think I’ll give this a try this winter.[/quote]
Go very light on the misting. Without any medium in there to soak the water up, the seeds can easily get oversaturated- at least they did for me last year.
Thank you for that tip Donald!
Thank you everyone for sharing your helpful experiences.
I ended up trying a few things:
Silica sand - good distribution of moisture, but hard to tell when the sand was too wet
Nothing, moist bag - it was too easy for me to add too much water. Worried I may have drowned some. I agree, need to go light on the misting for this one if I try this again. The simplicity appeals to me.
Perlite - Distribution of moisture ok
Peat moss - Distribution of moisture good, but bag looked muddy
And now I’m giving playground sand a try. I am liking how the sand stays clumped together and moisture levels look more obvious.
Instead of sandwhich bags, I am contemplating using smaller thicker baggies or petri dishes in the future.
Being the first time I’ve done this, even if I manage to get one seedling, I’ll be happy.
Roselynn - it never seems like any will germinate…and is so magical when they do.
Thank you jbergeson for the reassurance, I greatly appreciate it, especially as I look at my seeds wondering if I’ve provided them the optimum conditions or not. 
Roseseek, I also like your method of nothing at all (I assume with no added water) other than a ziploc bag, it is the ultimate in simplicity, I think I will give it a try next. One of my concerns this time was too much moisture.
Roselynn- it’s always suspenseful, waiting to see what sprouts. I have a few seed parents that I can count on for viable seed no matter what I do to them- Hot Tamale, Morden Centennial- and I always make sure to plant a fair number of those just to make myself feel better when my more difficult crosses don’t germinate.
The excitement and anticipation of seedlings germinating each winter is there each year for me.
This is my first year stratifying in plastic bags with no medium. I can’t comment on success yet, but they look good in the bags.
Here is my tip for getting well-moistened seeds with no excess moisture. First, I believe there should be something added to the water to make it stick to the seeds. A drop of dishsoap in a cup of water should do the trick, although I used a commercial substance called Capsil. It is easy to see when seeds that were floating on the surface tension of the water are no longer floating, or if they are they are submersed with water sticking to them rather than it being repelled by them.
After wetting the seeds by soaking in water with the Capsil (and calcium nitrate in this case), I dumped the solution out through a coffee-mug sized wire strainer. There is always some nested water being held by surface tension on the bottom of the strainer, so I briefly pressed the bottom of the strainer against an absorbent towel to wick away that moisture. After doing that the seeds could easily be tapped out of the strainer into the baggies. They were freshly and thoroughly moistened, but there generally wasn’t even a drop of excess moisture in the baggies.
I was pretty proud of this technique as it seemed to wet the seeds to the perfect degree, but keep in mind that I’ve never done it like this before so this is not expert advice.
Therefore, is it generally better to keep the seeds on the dryer side rather than the wetter side during stratification? I wish there was a way to measure what is moist, but not too moist.
Donald, it is great to hear Morden Centennial is good for viable seed, I planted her this year and was very happy with the abundant hips and OP seeds harvested.
Roselynn,
I do not think that you can keep your seeds to moist if you take care to drain off any excess standing water after a couple of days. Keep in mind that most species of plants did get carried on ocean currents for days as a way of spreading from continent to continent, or to some islands, and if they reached fertile soil, many did sprout and survive. It is possible to keep them to dry, however, and the seed covering does need to be rehydrated fully to enable germination.