My stratification methods for this year

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My stratification methods for this year

Postby jbergeson » Mon Nov 28, 2016 11:07 pm

I'll try to let you know in the spring how this all works out for percentages and the like.

I was inspired by the research article posted here a while back where they got significantly increased germination by soaking their seeds in straight bleach for two hours. So I decided I was going to try that.

Their bleach was 5%. I bought Clorox concentrated bleach at Costco which said about 8% available chlorine. So I mixed in a little less than half the bleach amount of water to reach an estimated 5% chlorine and got started soaking all my seeds.

I put them in a cup with a label and some of the solution. I got a little distracted, and didn't realize how long it would take to rinse the seeds, so the first batch were soaked for up to three hours. Gosh, were they white. Some of the smaller, greener seeds ended up almost translucent. Interestingly, the seeds that came from moldy hips and were black going into the treatment came out the whitest, almost translucent.

Despite a visceral attraction to the whiteness and purity of the bleached seeds, I started to suspect that in this case the solution might be more dangerous than the problem. However, I thought I should give this method a chance to succeed, so I added a little water to the bleach and reduced the soaking time for the next batches.

I then thought of another variable: I usually don't let my seeds dry out before sealing them in baggies. Maybe the relatively fresh seeds would be more absorbent to the bleach and it might reach the embryo and kill it. I got out my nail clippers and opened a few seeds and couldn't really tell, but when I tasted the embryo of a bleached seed I could taste the bleach. So I've likely killed 1/3 or more of my seeds for this year, but only time will tell.

Before I describe later experiments, let me tell you the rest of the procedure, the things that remained constant for all the seeds. For all methods I added a foliar adjuvant called Capsil to ensure good coverage of the seeds. I imagine this works like dish soap. Boy, could you see a difference. Many seeds will float just from the surface tension of the water. One tiny drop of Capsil allows them to submerge. Even seeds that still float are obviously suffused with water. I wasn't real careful about the amount of Capsil, but 1 mL seemed to be more than enough for a half-gallon of solution. It did seem like I had to add more Capsil the second day to a bleach solution, as if the bleach broke it down.

I decided I wasn't going to attempt to add too many variables, but wanted to try the calcium nitrate thing, so all seeds after the bleaching soak and rinse were soaked to varying lengths of time (1 hour to 7 hours, with the longer times being in a cooler) in a solution of one gently heaping small spoonful per half gallon of water. Also with Capsil. I didn't have a measuring teaspoon handy, so it was just a regular small spoonful, slightly heaped, and probably the solution was on the strong side. Then I dumped the seeds in a small strainer without rinsing. Pressing the strainer onto a towel sucked away the nested water at the bottom and allowed the seeds to be easily dumped into a snack baggie. I decided to use fresh baggies to avoid recontamination with mold, since many of my seeds end up getting moldy in the bag by this point. I did not use any vermiculite or sand, instead just putting the freshly moistened seeds into the baggie and sealing immediately. I would then seal a bunch of these snack sized baggies into a quart sized freezer Ziploc of higher quality so they don't dry out in storage.

Because of my bad percentages last year with a warm stratification period I have decided to take Don and Peter's advice and put the seeds immediately into the cold. I want to find as cold of a spot as possible to avoid early germinations, because I have too many crosses to be picking out germinating seeds and planting them one by one. I want to sow all of the seeds in March.

OK, so with 1/3 or half of my crossed seeds processed I decided to take a break and do some trials of bleach and Zerotol on OP seeds and those few crosses of which I had huge quantities of seeds. Zerotol is hydrogen dioxide, I believe, and works in the same manner as hydrogen peroxide. It should be noted that what is on the market now is Zerotol 2.0, which has an added ingredient, but I was using the original Zerotol.

The strongest dilution of Zerotol that is recommended on their website is 1:100. I figured if the foliage of a plant can handle that strength then I'd better use something like 1:20 as my primary dilution. Impressionable newbies should be advised that I might be an idiot.

The variables of my test were:

8% bleach diluted to half strength
Zerotol 100% (just a few samples for this)
Zerotol 1:1 dilution
Zerotol 1:19 dilution
Control Plain water

All solutions including had Capsil and I aimed for about 1 hour soaking time. All were then rinsed and treated with calcium nitrate. Fourteen seed parents divided into a total of 39 lots (not all parents were trialed for all four variables) for a total of about 5500 seeds. Most lots were 100 seeds, a few larger.

(Right at the end I relented and did one trial of calcium nitrate, just eyeballing an equal # of seeds, about 500 each of nitrate soak and a control plain water soak. Both presoaked with 1:19 Zerotol.)

For the rest of my controlled crosses I pretty much used a 1:19 Zerotol soak for one hour. In one case two crosses of the same seed parent were super black and moldy so I soaked one in 1:19 Zerotol and the other in 1:1 Zerotol. There was a color difference in the end result. I will post some pics.

I hope to find this thread in the spring and post results.
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Re: My stratification methods for this year

Postby jbergeson » Mon Nov 28, 2016 11:34 pm

Some pics. See photo comments.
Attachments
IMG_0662.JPG
Strong bleach soak
IMG_0658.JPG
Well bleached seeds
IMG_0657.JPG
Bleach soak
IMG_0678.JPG
Zerotol didn't bleach them like bleach, but the stronger solution made the lighter.
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Re: My stratification methods for this year

Postby henry kuska » Tue Nov 29, 2016 1:13 am

I question the universal use of Capsil. Unless you have a reference that Capsil is beneficial I would think that you have too many variables.
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Re: My stratification methods for this year

Postby jbergeson » Tue Nov 29, 2016 2:30 am

Quick response to Henry...

Without Capsil or a similar agent to combat the surface tension effect (I don't know how to say it technically), the rose seeds themselves would introduce a significant variable. For instance, rugosa seeds seem highly repellent to water and float on top of any of the treatment solutions unless an adjuvant is added. Other rose seeds are not so repellent of the water. A seed that is floating on top of the treatment solution due to surface tension rather than weight is simply not being exposed to the treatment. I can't stand the thought of my seeds not making full contact with the solution.

Intuitively, I feel that the Capsil will also help with the uniform moistening of the seeds in the bag during cold stratification. If the seeds vigorously shed the water as some seeds seem to do, there might end up being beads of water at the bottom of the bag with dry seeds above. With the use of Capsil it seemed to me that all the seeds were uniformly moistened and there was no excess water in the bag at all. So I am particularly enthused about using Capsil when stratifying in a bag with no added stratification medium.

Having said that, I make no pretense of scientific legitimacy. These tests are to satisfy my own curiosity and to measure any results that happen to be dramatic rather than subtle. My measurements were often imprecise (especially in regards to the Capsil...if it didn't seem to be working I dumped in some more). My counting of seeds is also imprecise; if a seed seemed significantly smaller than the others I sometimes wouldn't count it, or would count 2 or 3 small seeds as one. In several cases I didn't want to take the time to divide a batch of counted seeds, for hypothetical example 278 seeds, and just eyeballed them on a plate and called it 140 seeds each. Soaking times in the various solutions varied, sometimes fairly widely, about which I just took vague notes.

But I stand by my assertion that the use of Capsil actually reduces the natural variable of the hydrorepellency of different rose seed types. My assumption is that, as a horticultural product intended to be added to solutions that are sprayed on plants, Capsil will do the job of dishsoap with less chance of phytotoxicity. An additional assumption is that seeds, especially rose and other hard seeds, will be much less susceptible to any potential phytotoxicity than a leaf surface. These two assumptions together are how I justify my carelessness in measuring, although I admit that carelessness adds back an unnecessary variable.
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Re: My stratification methods for this year

Postby henry kuska » Tue Nov 29, 2016 12:41 pm

jbergeson, thank you for your reply. You are not considering what Capsil does when exposed to oxidizing agents like bleach or hydrogen peroxide. This is the label:
http://florawww.eeb.uconn.edu/msds/capsil_label.pdf

I do not know what the results of an oxidizing agent with Capsil will produce. Please consider the possible safety concerns of unknown reactions. For example: http://www.doh.wa.gov/YouandYourFamily/ ... ingDangers
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Re: My stratification methods for this year

Postby jbergeson » Tue Nov 29, 2016 1:43 pm

Thanks for the research and the warning, Henry. Too late for me but it is good to caution others not to blindly follow my reckless methods.
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Re: My stratification methods for this year

Postby philip_la » Sun Apr 02, 2017 12:03 pm

Well, methodology notwithstanding, I'm wondering if you had any successes...
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Re: My stratification methods for this year

Postby jbergeson » Sun Apr 02, 2017 9:04 pm

Thanks for the inquiry, Philip. I am just in the process of sowing my seeds. I haven't had time to finish, but I have looked in the bags to pick out any that are sprouting heavily or molding badly.

One apparent takeaway is DON'T SOAK YOUR SEEDS IN STRAIGHT BLEACH FOR TWO HOURS. I think I killed a lot of them. They still smell strongly of bleach. Keep in mind that they were not allowed to dry after shelling from the hip and before that treatment, so maybe the achenes were softer and more permeable. Interestingly, exactly one of the seed parents that had been bleached was sprouting heavily. Most of the rest are not sprouting at all when it seems like they should at least have a few sprouts.

The 1:20 zerotol treatment seemed to be fine. Mostly the seeds are brown. It did not always prevent molding. Many of my seeds have a lot of mold in the bag, so I am agitating them briefly in a mild zerotol solution & rinsing in clear water before sowing. Luckily it seems like even if some are sprouting the mold has usually not killed them.

I haven't had a chance to analyze and draw any conclusions from my bulk seed trials of various strengths of bleach and zerotol. I suppose the final germination count will be the best measure, but there are always multiple variables. In this case the varying degrees of mold is a variable that can't fully be attributed to the soaking solutions as different spores could have found their way into different bags. Will report more on this later.

I'm actually pretty happy with the method, new for me, of stratifying seeds in baggies without any medium. Of the ones I didn't kill I think my germination rates are higher so far. I definitely have some learning to do and some tweaking. I wonder if using vermiculite would reduce the molding and keep the moisture levels more consistent. But I can't imagine picking the seeds out from the vermiculite to sow them - it seems like it would be very annoying when planting lots of seeds. One thing I could maybe do is sow the seeds earlier before the worst mold kicks in - maybe around March 1st, and then store the seedling flats cold until April.

Summary: Too soon to tell. Seems like the strong bleach might have been a bad idea based on initial inspections. Seems like a 1:20 zerotol didn't have significant negative effects.
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Re: My stratification methods for this year

Postby philip_la » Mon Apr 03, 2017 1:15 am

Well, here's a question based on pure ignorance and speculation..
I will first say that I really cannot fathom the benefits of bleach on seeds beyond sterilizing, and the following is purely on a whim...

I recall some comments on hydrogen peroxide and have seen other claims of vinegar aiding germination. H2O2 and acetic acid combined create peracetic acid, which is frequently used as a sterilizer in food industries... It forms an acid which is somewhat milder than the acetic acid, I believe. Anyway, I'm wondering if one used e.g. 2 parts hydrogen peroxide (3%) to 1 part e.g. cider vinegar (5% acidity) -- which is recommended by some for seed germination, and derived from apples in the rosaceae to boot -- to make a sterilizing solution, if that would be worth trying.

I have another dumb question... Many years ago, Joan Monteith shared some seeds she had stratifying. The cross involved Mr. Nash and Rugelda. She hypothesized that it would be a good while before they germinated, but on a whim, she had stratified the seeds in activated charcoal, wondering, I suppose, if that might remove any potential inhibitors. By the time the seeds arrived in the mail, several were already sprouting.

Has anyone else tried this technique? I have not been able to contact Joan since then, and don't know if she has had other successes using that technique.
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Re: My stratification methods for this year

Postby jbergeson » Mon Apr 03, 2017 9:58 am

Knowing me, Philip, I'll stratify my seeds in a slurry of bleach, charcoal, hydrogen peroxide, and vinegar next year! ;-)

Maybe have to try adding some peanut butter.
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Re: My stratification methods for this year

Postby philip_la » Mon Apr 03, 2017 11:00 am

Remind me not to come over to your house for dinner. I would imagine you give new meaning to the idea of fusion cuisine. ;-)
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Re: My stratification methods for this year

Postby roseseek » Mon Apr 03, 2017 12:18 pm

I was just thinking what you wrote about not coming for dinner, Philip! LOL! Now we have citric acid herbicide easily available, perhaps it may be instructive to try some very weak solutions of citric acid to sterilize the seeds prior to planting? It isn't something I am tempted to try as I sow them pretty much as I harvest them. The weather here has worked well for planting several batches of seeds over quite a few months from summer to "winter/spring".
Kim
California Central Coast
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Sunset Zone 15
Cooler inland coastal valley with strong marine influence
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Re: My stratification methods for this year

Postby jbergeson » Mon Apr 03, 2017 2:15 pm

My wife feels pretty much the same way about my cooking, although in my opinion I occasionally have spectacular results.

I just got a five pound bag of citric acid in the mail, so I'll have to add that to the mix, Kim. Not sure why you say "very weak", though. :)
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Re: My stratification methods for this year

Postby Warren » Tue Apr 04, 2017 10:34 pm

Here is what I did when doing tissue culture. Make up a solution of 1:4 household bleach and water. Dip the seed in 70% ethanol and then soak in the 1:4 bleach solution for 5 minutes. this should get rid of any nasties hanging around.

Warren
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Re: My stratification methods for this year

Postby jbergeson » Tue Apr 04, 2017 11:15 pm

The bleach soak wasn't as 100% fatal as I thought. I am getting some sprouts even among the seeds that still smell like bleach after four months and were visibly scarified by the treatment.

My problem now is finding time to sow the seeds.
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Re: My stratification methods for this year

Postby Warren » Tue Apr 04, 2017 11:17 pm

You think you have problems, I am scratching my head where in the hell am I going to put all these seedlings from this year LOL.
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Re: My stratification methods for this year

Postby jriekstins » Wed Apr 05, 2017 11:00 pm

Warren,
If I remember correctly, I saw some pretty big fields in some of those photos you posted. Or are you trying to say that you have already filled them all up? Such a problem to have, I only have gophers and expensive water to worry about.
Joe, that is good to hear that some of the extreme bleach soaks are actually sprouting. Rose seeds are tough.
Philip, That is a great question/idea about activated charcoal---if I still think/remember that come October, I would love to try that.
]Jackie, SoCal., zone 9b,coastal foothills
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