Pulsatilla alpina --seeding questions

[Robert Pavlis]

I germinated some Pulsatilla alpina 'Sulphurea'  in baggies. Some seemed to die as soon as they were planted in Promix + grit. Others formed complete codelyden leaves and then sat there for a month or more before dying--the codelyden leaves slowly turned brown. The last few are now loosing the codelyden leaves and I dug down a bit to find a swollen tuber and in one case several new growths--one of which seem to be rotting.

Some questions:
1) Is it normal for the seedling to take such a long time before making a true leaf?
2) Should the swollen tuber be at ground level? maybe I planted them too deep and that is why the true leaves are rotting?

Any advice on seeding and growing seeds is appreciated.

[Gene Mirro]

I don't understand the whole baggie thing.  It just forces you to handle the seedlings when they are very delicate.  I just sow directly into 3.5 inch square pots.

A lot of alpines will die just as you described if you try to grow them at room temperature.  They need to be cool, 10 degrees C or less.  I have a fluorescent light rigged up in my cold greenhouse for growing these plants.  European alpine gentians like it really cool, down around 5-10C. 

A lot of other plants will grow well at around 15C, but will have problems above 15C.

Another possibility is that you stressed them when you transplanted.  Did you let the roots dry out?  Did you expose them to the sun?  Did you apply concentrated fertilizer?

This is one of my old posts that tells you how I grow difficult plants from seed:  http://www.srgc.net/forum/index.php?topic=71.msg722#msg722
This is too much fuss for a lot of gardeners, but the advantage is that I get very high germination rate and high growth rate, so I don't have to wait four years to see a flower. 

Edit:  here's another post that shows you how I use propagation domes:  http://www.srgc.net/forum/index.php?topic=1166.msg26355#msg26355

[Lori S.]

If you read Deno's publications, it is clear that the use of the baggies was to be able to conduct a very large number of germination experiments in a limited space.... a hundred baggies takes up much less room than a hundred pots, and it doesn't appear he was germinating seedlings for the particular purpose of growing them on, but rather, to understand the germination inhibitor mechanisms for each species.  I find (or found, haven't done this in some time) it does save space, of course, but only temporarily - if the germination is successful, they have to be popped up anyway.   

[Gene Mirro]

Another thing about Deno's germination rules:  he limits himself to just a few conditons to simplify things.  When he says a seed will germinate at 70F, he doesn't mean that you should GROW it at 70F.  For most alpines and a lot of perennials, 60F is as warm as you want to go.  For some alpines and a lot of north American wildflowers, 50F is better.  This is why it's important to sow your seeds no later than early Fall.  Otherwise germination is going to happen very late in Spring when the weather is too warm.  I usually store my seed exchange seed in the freezer until late the next Summer for this very reason.  This only applies to seed which requires a cold period to break dormancy.  Note that dry storage in the freezer does not count towards breaking dormancy.  The seeds have to be planted in moist soil and then subjected to a cold period in order to germinate.  The proper temperature for the cold period is around 40F, NOT freezer temperature of 0F.  If you place moist seed in the freezer, you will kill it, guaranteed.

[Robert Pavlis]

At this time of year I am growing at 70 deg (20 C) under lights so that may be a problem. I did not realize the need for lower temps--thanks for this info.

They don't get stressed when they are transplanted. A few seconds at room humidity, and then right into 100% humidity, mimicking the humidity in the baggies, where they get slowly conditioned to lower humidity. they don't get fertilized until they have true leaves and then only with very low levels.

Why baggies? I used to use pots, but for seeds that take several years to germinate, I would not give them the care they need over the summer too much drying out. The baggies allow me to easily give them cold treatment, I can see what is going on with the seed, I can pot them up individually for rare seed, and pot them up as they germinate for seeds that germinate over long periods of time. I am not convinced it works for everything, but it does produce higher rates for me than pots. Things that have not germinated by mid summer go into the fridge in the hopes they don't germinate until late winter when they get some warmth--so I don't have to deal with them in fall and early winter. I don't have a greenhouse. Unfortunately, this year I seem to be getting more germination than usual from things in the fridge.

I have 150 baggies in a very small space in the fridge at 10 C, but I'd have no way to keep 150 pots at 10 deg.

[Robert Pavlis]

Gene Mirro--I have always believed that cold dry storage does not qualify for stratification, but many web sites and seed companies say it does. So I agree with you. However, I'd be very interested in finding data that shows that this is in fact true.

I author a blog called http://www.gardenmyths.com/ and this is one of the topics I would like to write about, but have never seen scientific data to validate my position.

[Robert Pavlis]

Gene--thanks a lot for your posts.

I have been trying something new which is some what similar to your method. I do find that I loose some germinated seeds when I transfer from the baggies to the pots. I am not sure why. It could be the temperature and I'll work on that. But I have been checking the soil and the material I use to cover the seedlings--I don't think that is a problem, but could be. I may get them too wet? I may be planting too deep?

What I have tried over the last few weeks was to just lay the germinating seed onto the soil with no attempt to bury it. I then put it in a plastic bag. I had used this earlier for trillium seeds, just laying them on paper towel, with great results. I can see the development of the root and leaves. The seedling has 100% humidity.

Once the true leaves have developed and the root system is larger with root hairs, I slowly cover it with soil, or dig it deeper into the soil. So far it is working with 2 species I lost in the past. At the very least I hope to be able to witness the death of the seedling and maybe find out why I loose some seeds.

I plan to repeat this for my spring seedlings--50-100 species and then report on the results.

[Gene Mirro]

The method you just described is one that I use a lot, especially for tiny seeds.  As soon as they start germinating, I add a small amount of peat or vermiculite to the pot and cover them a little.  It works great. 

About wet vs dry cold treatment:  I have stored seeds in the freezer for over 30 years, and they still need a wet cold treatment before they will germinate.  I just googled "seed stratification techniques" and got 444,000 results.  I read ALL of them just now, and they all say you should moisten the seed. 

There are a lot of people on the web who are just quoting what others say.  What makes it worse is that people who talk about cold treatment do not explicitly state that the seed has to be moist.  I have even read that you should place moist seed in the freezer, which is clearly not going to end well. 

[Lori S.]

Gene Mirro--I have always believed that cold dry storage does not qualify for stratification, but many web sites and seed companies say it does. So I agree with you. However, I'd be very interested in finding data that shows that this is in fact true.

I author a blog called http://www.gardenmyths.com/ and this is one of the topics I would like to write about, but have never seen scientific data to validate my position.

Again, simply read Dr. Norm Deno's publications - thry're all on the internet now!!  I believe they are even posted at this site.
Edit:  Okay, perhaps they are not posted at this site (though they should be.    )
Here's a link to them from the NARGS site:   https://www.nargs.org/forum/link-pdfs-dr-denos-seed-germination-books

[Maggi Young]

Links to Deno's papers are listed at various places in the Forum - for example :

http://www.srgc.net/forum/index.php?topic=8368.msg311376#msg311376