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njbiology

For experts in cold-stratification -- native seeds.

njbiology
9 years ago

5 sets of questions regarding cold-stratification of seeds...

1. I began cold-stratification (moist peat, refrigerator) for most species that I have (dozens). Some of these species only require 30 days of stratification, and others require approx. 20 days. The only species that I did not began stratification for were the legume -- and that will be covered in my next question. So, for seeds requiring only 30 days (for instance Callirhoe spp.), will they germinate far too early? They were started on December 23... does that mean they will wake up from stratification in February or March, even though refrigerated? IF this is a risk, can I take any species out of the refrigerator and leave the individual moist peatmoss/seed filled bags open so that they dry out and then begin the process of stratification 30 days before spring? Or is it just that they NEED 30 days for a decent % of germination, but would benefit from the 90 days that I could give them in refrigeration?

2. For Agrostis spp. Surprisingly, members of this genus is listed as requiring 60 days of cold stratification. If this is so, same as with my first question. I feel that grasses -- especially those that do not require cold stratification (Soghastrum, etc.) -- will wake up in the refrigerator if given too long. I think that I'm taking a big risk by starting them now. The problem with taking them out of the refrigerator now is that if they do not absolutely require cold-stratification, they might wake up while I'm trying to dry the bags out for later starting the cold-stratificaiton process. I should have contacted you before starting all this, but hopefully you will let me know its ok to give seeds longer. Another idea would be to take the seeds out and direct sow them. I preferred to do things indoors because I have a seed bed (weed seed free soil) prepared so that when they are at the brink of germination, I could sow them and manage the bed for a year prior to transplanting.

3. For Phlox pilosa and other difficult-to-germinate (C) code species... can I place the moist bags in the freezer for two weeks, then the refrigerator? I read a research paper which indicated success with freezing -- but I don't recall whether the seed much be dry if freezing, and then moisture is added. P. pilosa shouldn't be allow to dry out, so I'm not sure. Also, I have a little bit of GA-3. Should I sprinkle a pinch into each bag of difficult-to-germinate seeds at the very end of the stratification period. I might even sprinkle some wood ash for tricky prairie species. I

4. Are high-PH species are best cold-stratified in clay rather than in peatmoss? Wood ash may help in such cases.

5. Although native the legumes are listed as requiring just 10 days of cold-stratification (cf: PM Nursery, etc.), the seed (various species) I received have not been scarified. Do you recommend that I wait until the very end of spring to begin cold stratification (with use of the species-appropriate inocula)? Or, because they have not been scarified, should I begin stratification at this time and in a few months (end of winter), add the inocula? The only species I haven't begun stratification for were the legumes because I could see 60 or 30 being stretched out to 90, but not 10 days.... unless not using the incolum for a species until the end will ensure the stretch is achieved. I'm just concerned that 10 days is not enough since they haven't been scarified.

Thanks!

Hopefully many will benefit from responses to these 5 questions.

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