Germinating seeds

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julie777
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Germinating seeds

Post: # 70926Post julie777
Sun Jan 19, 2020 2:19 pm

Last October I planted a lot of rose seeds outside in pots of compost mixed with perlite. I got them from a variety of hips, some very red, ripe and mushy and some still green but the seeds inside them looked as though they were fully formed. Where I am on the south coast of England, zone 9, we have very mild winters and February is the coldest month. Now in late January days are noticeably cold whereas up to the end of December the weather was still very mild. We very rarely get snow or the temperature dropping below freezing. No snow yet this year, but plenty of rain.

I didn't stratify my seeds in the fridge, as I assumed that the winter would do that for me. It has rained a lot and outside compost is always damp. No sign of anything germinating yet, but I read that seeds usually germinate in late March, which makes sense as the cold weather would kill off any tiny seedlings, and the rainy weather attracts slugs that would eat them. Even though my roses happily flower all winter, they always look battered after periods of strong wind and rain but usually recover.

My questions are, do seeds also need the warmth of spring before they will germinate, as well as the cold stratification of winter, which in the UK is January and February? And do some rose hips stay green even when they are mature? I have noticed that hips on cultivars always seem to stay green, and only species roses make red hips. I am wondering if October gathered rosehips had time to mature.
Zone 9.

Plazbo
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Re: Germinating seeds

Post: # 70928Post Plazbo
Sun Jan 19, 2020 4:30 pm

Yes and no.

It depends a bit on class/species. I mean things closely related to species that rarely/never seen freezing temps arent likely to need stratification.

Probably also location. My seeds often never seen spring.

Im in Sydney Australia (very little chance of freezing, even then never really frozen, just a thin layer of sleet) and I sow seed in march (autumn), and can have first bloom by winter. Other things take longer to germinate or bloom.

Either way ive had gallica/centifolia hybrids and rugosa germinate without stratifying.

The only things ive had no success with is the pimp group (ie spinosissima, xanthia, hugonis, etc) but thats likely more to do with them taking 2 years to germinate from what others have said (soooo maybe something will turn up in their trays in a few months)
Anyone able to send rosa californica (op) seeds to me in Australia?

roseseek
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Location: Zone 9b Central California, Sunset Zone 15
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Re: Germinating seeds

Post: # 70929Post roseseek
Sun Jan 19, 2020 4:44 pm

I'd read repeatedly that germination stopped as temps rose to the 70 F levels, except mine regularly continue germinating well into the 80s F. They will germinate in a refrigerator at temps just above freezing, so why shouldn't they also try it in your pots? Do they need "warmth"? Probably some genetic combinations do, but not all, otherwise why would they do it in a cold refrigerator? They obviously don't need extreme cold stratification (again, depending upon genetic combinations) as I haven't provided anything "colder" than the fifties F in years and I always have far too many seeds and seedlings to play with. I bet if you were dealing with extremely Arctic hardy things, the answer would be vastly different, but if you're using moderns with some OGRs, minis, "regular species" which aren't overly cold hardy, they don't require it. Yes, some hips never change color. Others become highly colored, just as some apples remain green while others are anything from nearly black to orange, yellow, brilliant red and every combination in between. Ever hear of hips being called "rose apples"? Guess why. Generally, if the seeds are at least 110 or so days from pollination, they should be "ripe".
Kim
California Central Coast
USDA Zone 9b
Sunset Zone 15
Cooler inland coastal valley with strong marine influence

mntlover
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Re: Germinating seeds

Post: # 70930Post mntlover
Sun Jan 19, 2020 4:47 pm

color of rosehips vary at ripe stage, experience with a variety helps in this.
I have seeds germinate in the fridge while in cold storage. However, germination seems to increase when moved to a warmer temp. (50s and 60s). Perhaps some even require the warmer? Others could probably give you accurate information on that.
Also, there can be a great deal of time difference in length needed till germination.
I would recommend a search on here of "stratify, ied, ication" and "germinate, ing" etc.

Duane

julie777
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Re: Germinating seeds

Post: # 70933Post julie777
Sun Jan 19, 2020 8:10 pm

I wondered if rose seeds require a cold period followed by a warm period to germinate, which happens when you get a cold winter followed by spring. Needing a cold period would stop the seeds from germinating immediately in the late summer and autumn, as the seedlings wouldn't have enough time to grow to a decent size before winter and therefore vulnerable to being killed by the cold? Then needing a warm period would cause them to germinate when winter is over.

At the moment our temperatures are between about 1 degree Centigrade (33.8 Fahrenheit) and 3 degrees Centigrade (37.4 Fahrenheit), but in December they were more like 9 degrees Centigrade (48.2 Fahrenheit). Our typical summer temperature on a nice day is 26 degrees Centigrade (78.8 degrees Fahrenheit). Our temperatures very rarely drop below 0 degrees Centigrade, it almost never gets cold enough to snow.

I am guessing that the seeds I have are somehow adapted for this climate and will fingers crossed germinate after about late March. There could be epigenetic reasons for that.

I will search on here using those search words, thanks.
Zone 9.

Larry Davis
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Re: Germinating seeds

Post: # 70934Post Larry Davis
Sun Jan 19, 2020 10:33 pm

I tried a post earlier but it disappeared. Look on the home page for RHA, under publications. You will find a review that I wrote in 2010. It cites Tincker, at Wisley in the 1930s burying seeds in pots of damp stuff for the winter to vernalize and getting good germination when he took them out and planted them. So with your temp regime which is somewhat cooler than in southern France, where folks planted directly in fall, things may be later emerging. But as noted by roseseek, for HT, FL etc even warmer winter temps are OK.. and for more northerly species, colder ones are probably fine.

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