Seed failure.

A meeting place for rose breeders.
Post Reply
roseman
Posts: 1
Joined: Sun Nov 14, 2021 5:38 pm

Seed failure.

Post: # 73491Post roseman
Sun Nov 14, 2021 5:56 pm

671B5E18-C760-49B0-AF48-830B4D467133.jpeg
Hi Everyone,
This is my first post on the forum. You all seem like great and helpful people here. I’ve been cloning roses for a few years and decided to try my hand at hybridizing this year. I planted my first batch of seeds in plastic jiffy grow trays with sterilized seed mix, about a quarter inch down, with a light mixture of super thrive, experimented with placing them inside and outside (my falls are pretty mild here in Redondo Beach California) and so far the only result from my efforts has been a few roots breaking the surface of the soil. I think maybe I kept my soul too wet. I also stratified for eight weeks in my refrigerator at 34°, and wonder if that was just too cold. Would appreciate any diagnostic help as far as what I did wrong.

roseseek
Posts: 5333
Joined: Sun Dec 11, 2011 6:54 pm
Location: Zone 9b Central California, Sunset Zone 15

Re: Seed failure.

Post: # 73492Post roseseek
Sun Nov 14, 2021 6:39 pm

Welcome! I moved on from these small cell potting types because they were impossible to keep properly moist and they were too subject to temperature extremes. If you have outdoor space, you will very likely benefit from planting in larger boxes outdoors so the soil will retain moisture and you will benefit from the day to night temperature changes. Rains will also assist as the seeds KNOW the difference between hose water and rain. The first issue with your inquiry though is, you didn't indicate how LONG you have waited for germination. I've had some seedlings exit the soil in seven to ten days from planting while others required two years. Literally. Thirty-four degrees isn't too cold, but it may delay germination longer. You also don't mention what type of rose seeds you're planting. Minis seem to germinate significantly faster than some other types and some species can really require a long period of stratification before they cooperate.

I have planted my seeds outdoors for the past 35 years in the San Fernando and Santa Clarita Valleys and now in the Santa Maria Valley. I decided on planting around the week of Thanksgiving many years ago because it was the last of my "spare time" until after the end of the year due to work and family requirements; and it was when the temperatures should fall into the range more suitable for germination and when the rains historically began. Of course, in later years, the temperatures and rains have changed dramatically, but outdoors is still the preferable practice.

If at all possible, I would use wooden boxes, either commercially available planting boxes or a type you can easily and inexpensively make using commonly available supplies. Please feel free to take a look at my blog post about it here. http://pushingtheroseenvelope.blogspot. ... ables.html I've been using these boxes for the past nearly 30 years with good results. Each one holds approximately four cubic feet of potting soil, giving seedlings plenty of root room to develop. If you build a frame about 18" tall above the box and staple either nylon window screen or plastic hardware cloth over three sides and the top, while leaving the bottom of the side you most easily access the table free so you may flip the side over the top to gain access, you can keep any rodents and birds out of the table as both ADORE rose seeds! The high frame over the top will allow seedlings to grow taller and provide you some time before you must remove them so that can be scheduled to your time, energy and the weather.

Of course you can create smaller versions of the above to fit your desires and needs. You just want them large enough to prevent being overheated in direct sun and by any "unseasonably hot, windy" weather events, which are more and more frequent. Also, living in similar conditions to where you are, I have found that using Miracle Gro Moisture Control Potting Soil, the blue and green bag and NOT the "organic" material in the white bags from landfills, has worked quite well. With the reinforced screen bottoms, drainage is superb, even during extreme rains. The soil type retains good moisture levels even when the aridity is higher and the winds extreme. If you desire, you can lighten the seed cover by adding perlite or even using a seed starter mix to cover the seeds, but the moisture control soil is perfect in the SoCal climates.

Please feel free to browse the blog if you desire and ask any questions you may have. I do wonder, however, if the issue you feel you are experiencing may simply be possibly not waiting long enough for germination of seeds which may be a bit longer delayed due to the lower stratification temperatures and the seeds not receiving the proper stimulation from the weather by not remaining outdoors for the greater extremes between day and night? Good luck!
Kim
California Central Coast
USDA Zone 9b
Sunset Zone 15
Cooler inland coastal valley with strong marine influence

henry kuska
Posts: 1119
Joined: Thu Dec 15, 2011 9:06 pm

Re: Seed failure.

Post: # 73493Post henry kuska
Sun Nov 14, 2021 8:28 pm

I placed my boxes right on the soil (zone 5 northern Ohio). I used metal screens to prevent the "critters" from gnawing through plastic type screens.

Plazbo
Posts: 219
Joined: Tue May 09, 2017 12:18 am

Re: Seed failure.

Post: # 73495Post Plazbo
Mon Nov 15, 2021 2:44 am

I'm on the other side of the pacific (Sydney, Australia) but similar monthly avg temps, just have rain year round.

I sow outdoors beginning of March (first season of Autumn/Fall and sow what ripens later as it's ready) without stratification, around mid to late March is around the time min temps start to fall below 15c/60f somewhat consistently, seems roughly required to get germination, don't seem to get much if any germination when min temps are above that here.

Similar to Kim in using long, wide planters, outside of pulling out duds to bin or exceptionally vigorous seedlings to pot individually most seedlings will be in the box a long time as I'm not doing much outside during the day from mid spring onwards, the sun is just too harsh for how pale I am.

As for what you've done wrong, possibly nothing. May just need more time, may have been dud seed (eg Sunny Knock Out and Golden Wings make a lot of seed but not a lot of germinations). May be helpful to post who the seed parent/s are to seem if they are a difficult parent.

roseman777
Posts: 3
Joined: Sun Nov 14, 2021 5:34 pm

Re: Seed failure.

Post: # 73514Post roseman777
Sun Nov 21, 2021 4:05 pm

Had to change my username because having trouble with account activation.

Thanks you all so much for the comments and advice. Much appreciated!

I’ve been hybridizing a wide mix including high and yellow flame, ebb tide, Don Juan, golden opportunity, graham thomas, beloved, and wildfire. A mix of hydrid teas, climbers, floribundas, and even an old English rose. I’ll look to give your techniques a try.

One question I still have is what does it mean when all I see is a root breaking the surface?

Also, I’ve read that I should keep the seedlings at 70 Degress but your advice was to expose then to extremes. Curious as to the reason for this conflict.

roseseek
Posts: 5333
Joined: Sun Dec 11, 2011 6:54 pm
Location: Zone 9b Central California, Sunset Zone 15

Re: Seed failure.

Post: # 73515Post roseseek
Sun Nov 21, 2021 4:22 pm

I had routinely read that germination occurs at temperatures below 70F. From observation, germination can continue well into the mid to high eighties as long as evening remain cool (fifties to sixties). "Extremes" meaning nights of high forties and above and days into the seventies or so. That range usually indicates the season is moving from "winter" into "spring" when they safely germinate. If the temps are too low, they "know" is is unsafe to germinate due to potential for freezes. If the temps are too high, they usually stop because they "know" the chances of survival are too low due to being cooked, fried by too high heat or extreme sun. You want a range of temperatures between the very cool nights and warm but not blistering days as the seeds pop out of the ground quite well at those temperatures. As for "root breaking the surface", I"m sorry but I have no idea what you mean by that. It is something I have never observed. Roots tend to grow with gravity. Stems grow against gravity, toward light. Roots grow away from light.
Kim
California Central Coast
USDA Zone 9b
Sunset Zone 15
Cooler inland coastal valley with strong marine influence

mntlover
Posts: 397
Joined: Sat Dec 29, 2018 7:11 pm
Location: Mazama, WA

Re: Seed failure.

Post: # 73532Post mntlover
Thu Dec 02, 2021 12:36 pm

I don't know about the others, but Graham Thomas was one of the first few seed parents I used.
If I remember correctly, I kept the seeds in the fridge for two or three months (in damp paper towel in a ziploc), then planted in a tray and had in room where I kept the temp. between 50 and 60 degrees.
The seeds germinated really well under those conditions. I don't remember exactly, but I think there were more than a hundred seedlings that first year.
I don't know how they will germinate under other conditions, but those conditions seemed to work well.
Duane

roseman777
Posts: 3
Joined: Sun Nov 14, 2021 5:34 pm

Re: Seed failure.

Post: # 73541Post roseman777
Sat Dec 04, 2021 5:43 pm

Thanks!

I’m wondering if I should take my current seedling trays which are still not showing any sprouts after a few months, and either put them outside, or put them in a spare refrigerator, to see if they just need to be stratified further. Any thoughts?

roseman777
Posts: 3
Joined: Sun Nov 14, 2021 5:34 pm

Re: Seed failure.

Post: # 73542Post roseman777
Sat Dec 04, 2021 5:44 pm

I also wonder if I just cut the soil to damp for too many weeks after the original planting, and if all the seedlings are probably just rotted under the surface and it’s time to start over

mntlover
Posts: 397
Joined: Sat Dec 29, 2018 7:11 pm
Location: Mazama, WA

Re: Seed failure.

Post: # 73544Post mntlover
Sat Dec 04, 2021 6:27 pm

you might try putting in a refrigerator for a while and then bringing them back out to see if you can jump start them.
Or perhaps see if you can find any seeds left, to know if they are rotted or not?
Duane

Karl K
Posts: 1452
Joined: Sat Jun 02, 2012 4:49 pm

Re: Seed failure.

Post: # 73601Post Karl K
Fri Dec 24, 2021 6:20 pm

Germination is a surprisingly complicated subject. Various structures in the seed may postpone germination by blocking water from penetrating the seed, or inhibiting gas exchange. These factors get confused with others, so ...
Botanical Gazette, 47(4): 341-342 (Apr 1909)
Germination and Light
William Crocker
It is surprising that experimenters are so slow to see that the proper test for dormancy of an embryo is to free it from incasing membranes with aseptic precautions and then to subject it to germinative conditions. This treatment will probably show the cause of most cases of delay to be in structures surrounding the embryo. If such treatment shows real dormancy of the embryo, as in the radicle of the hawthorn,14 it is then necessary to find the particular process that is delinquent. This is certainly possible in the light of the great progress that is being made in studying the catalytic nature of protoplasmic activity. When cases of delayed germination are investigated in this way, we may hope for progress. But to assume dormancy is merely marking time and leaves the physiology of delayed germination, as it is now, more than ten years behind other phases of plant physiology.
With these factors out of the way, we can concentrate on three things: after-ripening, chilling requirement and compensating temperature.
1) After-ripening is a biological process that generally occurs at low temperatures, at least for plants of the Temperature regions. Crocker (1925) discussed this.
Dormancy in rose seeds is a very interesting story but time and space will not permit its telling in detail. Rose hybridizers stratify these seeds in a cold place. Under this condition the seeds gradually germinate through a period of five to seven years—a long time to wait for the last seedling of the hybrids. Fortunately, science has stepped in here and helped. First, it has shown that the embryos themselves are dormant and that these embryos must go through some very definite and important chemical changes, called after-ripening, before they are ready to grow. Second, science has shown that these changes occur most rapidly when the germinator or stratification bed is held at 41°F. Under this condition the seeds of all the rose species tested to date will after-ripen and germinate within 140 days. Some of the hybrids offer much greater difficulty. It has also been shown that when the stratification bed rises considerably in temperature the seeds go back into the dormant condition. Thus in the old stratification practice much that is gained in the winter is lost the following summer. This old method was a good one but it lacked one very essential feature—that of controlled temperature in the stratification bed. The new method saves time.
2) Chilling requirement is another way of saying that species differ in the length of their after-ripening phase. Risley (1958) pollinated 'Skinner's Rambler' by various pollen parent, and found that the number of days to germination ranged from 83 to 173, depending on the pollen source.
3) Compensating temperature was described by Stewart and Semeniuk (1965) as "that temperature at which mature, moist seed does not germinate, after-ripening does not take place, and dormancy does not change. Seed germination was reduced by interruption of the after-ripening period with intervals at temperatures above the compensating temperature. The interruptions were more effective in reducing germination when more frequent and when the temperature during the interval was higher. Species differed in their sensitivity to high-temperature reduction of germination. Those having the longest after-ripening requirement were most sensitive. Germination of seeds which had the minimum after-ripening treatment was repressed more by high temperature than germination of those seeds which had an excess of after-ripening. The decrease in germination resulted from imposition of a secondary dormancy of the embryo, and probably also from reversal of the after-ripening effect upon the primary dormancy imposed by the seed coat."

After-ripening is especially important to understand because it can influence the future quality of the clone. This falls under the heading of Physiological Predetermination, but I won't go into that now. Instead I'll quote this very old experiment:
R. Buist, Florist, &c, Philadelphia. (1838)
Sir,—Some time last year I observed in your Magazine, a difference of opinion between two of your correspondents, in regard to the vegetating of rose seeds. I then determined on sowing some of the many varieties, and send you the result of my experiments.
No. 1. Seeds of Rosa indica odorata, or tea rose, were sown on the first of December, 1837, and vegetated in a temperature of between 58° and 65° Fahr., in from six weeks to three months, coming up occasionally during that period; the most of them have now bloomed, but not sufficiently strong to determine their character.
No. 2, of the same seed, and picked at the same time, was kept four weeks in sand, and sown on the ninth of January, 1838, and vegetated generally in seven weeks. The plants grew stronger and flowered better than No. 1, although treated in the same manner.
No. 3, seeds of the same, kept in sand till the first of February, and sown in pots and placed in dung or manure hot-bed, vegetated beautifully in six weeks, temperature from 65° to 75° Fahr., and are now promising, in growth, bloom and character, to surpass Nos. 1 and 2.
In this case it paid to wait until after-ripening was completed (or nearly) before sowing the seeds. There is more to a plant than its genotype.

Post Reply