I sowed some of these in insert trays, thinking I might set them outside under some cover for "winter sowing" stratification:
- Columbines (Aquilegea hybrids? ... "McKana's Giant Blend"),
- Penstemon strictus ("Rocky Mountain Blue")
- Delphiniums (D. elatum "Pacific Giant Blend" and D. grandiflorum "Blue Mirror"),
- Rudbeckia fulgida Goldstrum
I held them for a 2-3 weeks indoors "while thinking about it" and behold, all but the Rudbeckia have sprouted - like 50% or more. The Columbines and Penstemon came up especially well! Going by reading, I thoguht they all needed moist cold stratification.
I know my bedroom isn't cold enough to stratify them, especially that fast.
I know the seed store I got them from in year-end sales, and it isn't THAT humid or cold.
Some went in and out of the fridge in double plastic ziplocks, inside plastic jars for a few weeks, but there was dessicant in the jars keeping them at or below 10% RH.
Is stratification just for those who want to be able to say that they got very high germination?
Or did I just get lucky and should not expect a repetition?
I would have expected 10-15% to have escaped dormancy, but not this high a percentage. I got as good germination from Columbines and Penstemon than I sometimes get from annual seeds (maybe adding sand to the mix and watering less helped).
It certainly is not my green thumb: I'm more like "all thumbs". Maybe 10-15% of the Butterfly Flowers (Asclepias tuberosa) that wound up in one of those trays sprouted, and they AREN'T supposed to need special treatment to break dormancy.
I know that dwarf delphiniums and most rudbeckias don't need cold stratification,
because I've started them indoors. I always thought that columbine needed it, but maybe I'm wrong. Guess I'll try some indoors this year. I don't know about penstemon because the only one I can overwinter is "husker red", so I don't bother with them.
I think one of the variables that we can not control sometimes is the age of the seeds.
I used to wonder why I experienced different seed germination than the data bases, and have come to the conclusion that it is the age of the seeds which may have been different.
For example: seeds which need light or darkness when young ------may not require that when older.
In general, hybrids and selections of many plants have a much less (no?) need for stratification than native species. Age (as mentioned above) can also have an effect on stratification requirements, but unfortunately that is not consistent among species. With some species, stratification is a must with fresh seed, but older seed of the same species will germinate without treatment. With other species, the reverse is true. I have also seen some reporting the need for stratification with certain species, when what is actually needed is a very cool germination temp (as germination is inhibited by warmer temps).
My experience with the species you mentioned: Aquilegia - I grow many of the species and everything gets a stratification treatment (even the hybrids because I plant them all at the same time). Penstemon - same as Aquilegia, everything gets stratified and germinated at a cooler than normal temp (I have also played around with GA3 treatment for faster germ). Delphiniums, I don't stratify, but I try to germinate them at less than 60 degrees. Rudbeckia - I never stratify. Asclepias tuberosa - I get zero germination without stratification.
To summarize, I stratify everything I think might need it. I usually seed those needing stratification right after Thanksgiving, put them in the garage and forget about them until about March. Whether they have truly needed it or not is irrelevant as the cold will not hurt them and I usually get good germination from everything at about the same time.
>> have come to the conclusion that it is the age of the seeds which may have been different.
For example: seeds which need light or darkness when young ------may not require that when older.
>> In general, hybrids and selections of many plants have a much less (no?) need for stratification than native species.
>> Delphiniums, I don't stratify, but I try to germinate them at less than 60 degrees. ...
>> Asclepias tuberosa - I get zero germination without stratification.
Sounds wise to me. Thanks! These are all year-end-sale seeds.
Maybe sitting on the rack in the store gave them enough humidity that cool evenings gave them what little stratification they still needed.
>> Rudbeckia - I never stratify.
Maybe my Rudbeckia are resisting sprouting for other reasons.
You say Asclepias DOES need stratification? ... darn and rats! The seed packet did not mention that (Asclepias - tuberosa shrub-like plant - milkweed family)! "Plant outside after all danger of frost, up to 8 weeks before fall frost". I guess that expects the seed not to rot or be eaten through summer and fall, to sprout next year.
Re columbines, named varieties of A. vulgaris, like the McKana's Giants, don't need any stratification. The species (wild) version of A. vulgaris does, as well as A. canadensis, fragrans, rockii, and others.
Cold stratification is mostly for certain types of perennials. It does not help to cold stratify stuff that is easy to germinate, like morning glory, poppies, and whatnot.
Now that I have some perennial seedlings in propagation trays, I'm trying to decide the best way to over-winter them. In their trays, on the porch, covered and watering as needed? Put them in to the ground and subject them to slugs, squirrels, rain and rot? Pot them up to 3 1/2" or 4" pots and cover those on the porch?
One of my goals is to minimize the amount of squatting and reaching I have to do, especially trying to bend AND reach at the same time while trying not to fall down or destroy a seedling. Bad legs and shaky hands.
When I stratify perennial seeds, I use the method Norm Deno describes as Outdoor Treatment. I don't put the seeds in soil. Instead, I put them in a paper towel that has been wet with a solution of water and liquid kelp and then wrung out. Using kelp is my own contribution to this process--it helps with germination. Sprinkle the seeds on a quarter of the towel and fold up, gently pressing together. Put the towel in a cheap plastic baggie (cheap plastic lets in more oxygen), like the kind that does not zip. Label. Put all the labeled baggies together in an open box in a protected area outside like an unheated garage, a shed, or a covered patio. I use a metal cabinet on my roofed patio and put the baggies in an uncovered plastic box. They don't need light or anything. You can stack the baggies. Leave them out there through the winter. The water will freeze, but that does not hurt the seeds at all. Check for germination in the spring by opening up the towels. Then instead of trying to dislodge the seeds' roots from the paper towel, just rip off pieces and gently fingerpress them into the top of wet planting medium. They grow right through, no problem. I use peat pellets, but whatever floats your boat. And that's it.
This method has increased my germination rates for perennials massively. It works way better than putting the baggies in the freezer or than putting the seeds in actual soil that's left outside. You can do that, but like you say, it means bending over and lots of planting and soil and trays and whatever for things that might be DOA. With the paper towel method, all you lose is a paper towel and cheap baggie. It's also compact. One year I germinated 75 different seeds using this method. And they were all in a little box in my unheated garage.
For seeds that require extra cold, like aconite species and other members of the buttercup family, he recommends putting the seed in soil in a pot and then putting the pot in an open plastic bag, all of which is put against the north wall of the house, where the coldest temps are. I tried this with Aconitum napellus and hemsleyana, and it worked--when I could not get napellus to germinate even using a deep freeze. I think it's the temp fluctuation that's key.
None of this is worth doing for annuals. They germinate just fine at cool room temps (or spring weather) and in relatively short times. With named columbine varieties, I just plant them in peat pellets and grow them to transplants under shop lights in the basement, to get a jump on the season. I have also just harvested the seeds from my columbines in my yard and thrown them on the ground, which isn't the best method--inefficient--but works. I have done this with annuals that seed a lot too. It doesn't always work and isn't good for small seeds, but it sure is easy.
>> Sprinkle the seeds on a quarter of the towel and fold up, gently pressing together. Put the towel in a cheap plastic baggie
>> labeled baggies together in an open box in a protected area outside like an unheated garage ... They don't need light or anything. ... The water will freeze, but that does not hurt the seeds at all. Check for germination in the spring by opening up the towels.
>> With named columbine varieties, I just plant them in peat pellets and grow them to transplants under shop lights in the basement, to get a jump on the season.
I didn't realize Columbines have delicate roots. I had better pot them up from the 50-cell deep tray into 3-4" pots before frost.
Thank you! Baggies-in-the-fridge were something I was thinking of doing, but who has empty shelves in their fridge?
Corey ~ I picked up a small fridge at a Thrift Shop last year for $25.00. It is very small but perfect for seeds and bulbs. When not in use, I just unplug it. It is good for starting some in summer when it is too hot here and they need cold, then warm.
The Deno method also looks to be more efficient than what I had going last year with pots and flats everywhere. Still there will be a few I want to start early with heat inside. I may try a few more with the Deno method just to keep things cleaner as I had pots and trays and lights in my bedroom with heating pads underneath. Now I got some proper heat mats and a thermostat.
Here is the Deno method I use on Daylilies, and hardy perennials. I use Peroxide mixed with 10 part water to 1 part Peroxide to soak the paper towel in. Prevents mold. .
I have had the best luck to soak seeds overnight in hand hot water. Then put them in a damp kitchen towel folded over, and placed in a small plastic bag. I place the bag in the fridge for a minimum of 3 weeks for stratification. After 3 weeks, (6 weeks for hardy perennials) I take the bag and place it in room temp until sprouted. I check on the seeds every 3 days and plant those that have sprouted.
I use the small craft plastic bags available in Walmart. They are just large enough to hold one folded seed package. If youi have several, stick the bags in a bowl, or plastic container that salads come in.
This is the only method I use now to start seeds with.
Below are Columbine seeds just prior to pottine up.
i've always winter sown columbine and transplanted self sown seedling (usually) found underneath the leaves of other growing plants. However, i tried a native CA seed i harvested from my garden and am now trying to winter sow rocky mountain in my mini greenhouse. I'm thinking the native ca wasn't old enough and now i'm curious if the rocky mountain will have enough cold here, we'll see. This is all very interesting, very educational! I love it. Thanks for being creative thinkers and questioning minds. Also, i use a little sandpaper on my columbine seeds before i sow them. it seems to help, i think.