Larry Davis’ results using calcium nitrate on KO is fascinating. I am about ready to cold stratify my seeds and want to review the process. First: dilute 1,to 1 1/2 tsp of dry calcium nitrate in a gal of water. Then, using 1 part vermiculite to 2 parts diluted solution, wet vermiculite and use accordingly in baggie(or container)with seeds. I am assuming that there is no specific amount of required vermiculite plus solution per each container-except perhaps enough to expose each seed to the moist vermiculite. And then refrigerate, and in approx 60 days sow or warm stratify. Is that approximately correct, or are there any nuances?
We’re not to the stage of nuance yet. I used 30 g, one ounce, of the moist vermiculite in a baggie with about 100 seeds- 50-200 depending on availability to test several conditions. With 200 seeds, that’s pretty crowded, but the results still look good. this year is repeating findings of last year, with more CVs. I will be writing it up for winter, or next, whatever, newsletter.
I do not sow the seeds. I pick out the germinated ones from the vermiculite and transplant to potting mix. that’s because I have a long-=term expt going. what I would do is plant all when the first 5-10 % of seeds have popped, if I had to do it all at once.
I actually pick out the germinating ones also, and do not sow the balance. When they appear to be done germinating, I allow them to dry out. Locally all I can find is calcium nitrate/ ammonium nitrate, which probably is not as good? will get some overpriced calcium nitrate on line, which is available.
I am testing ammonium nitrate now. Potassium nitrate is OK. My impression is that I’m simply getting more nitrate when I use 10 mM of the calcium salt (2x) compared to the potassium. When I diluted the calcium nitrate to 3 mM or 1 mM I saw results drift back toward the control. I know that 20 mM of calcium nitrate was too high in at least the first year’s study. I initially thought that calcium was important, but I’m not so sure of that. Too much ammonium is probably toxic so I hesitate to recommend ammonium nitrate at high levels for anything. But I cannot yet say definitively that is would be bad. Nor can I speculate on a mixture. What is the ratio of calcium nitrate to ammonium nitrate in your source? If it is easy to get, I should test it so people will know if its safe or not.
One further point. So far I have not found any CV for which calcium nitrate gives poorer results than the control. For most it hastens germination, without increasing the overall level. But for some it appears to give a big boost in the % germ within a year. I am testing seeds of a few more species this year to see if they respond as do the repeat-blooming CV that I used previously. For a couple species the answer is yes.
The local chem supply co. carries (and my husband did purchase yesterday-so will try it unless I find out something negative otherwise)a solution grade calcium nitrate 15.5-0-0. It is made up of 1.0% Ammoniacal Nitrogen and 14.5 Nitrate Nitrogen (per label)total Calcium 19%, water soluble, derived from hydrated ammonium calcium nitrate double salt. I notice that in the winter 2010 RHA newsletter that there is a specific note about that. If you can comment on that. I was of the belief that calcium nitrate was calcium nitrate, but I am far from being a chemist.(Kind of like sugar is sugar, but not really.)
That is almost calcium nitrate with only a little ammonium thrown in. Because the molecular weight of N is 1bout 14 and you have around 14.5 grams per 100 grams as nitrate N and 19 % calcium you do have essentially two N for every Ca (molecular weight 40), but there is enough water (hydration) so that it is somewhat less concentrated than pure calcium nitrate. But it is only about 12 % low. Only question is if the ammonium matters. It is a very little amount so I’d think not.
Dear fellow rose hybridizers
I live in Denmark where I run a rose nursery. My hobby is hybridizing roses. In the cold climate we have here, I find better results in germination, when the seeds have got 2 month of warm stratification ( 20 grade Celsius) after harvest in October. This year I have given 1 and a
Thanks for adding your voice to the forum, Knud! I hope you will report back about the results of your experiment.
I don’t think anyone quite knows how nitrate is effective. From earlier work described in the RHA newsletter I think I’m fairly confident that it is not just salt. I tested calcium chloride and that is no better than plain water, sometimes worse. Also I tried the macronutrients in Hoagland’s solution- that is potassium acid phosphate and magnesium sulfate and some potassium nitrate. That does no better than water. As mentioned somewhere in a recent thread, lower levels of calcium nitrate work less well and double seems to be too much. Potassium nitrate was OK but the dose I used was only half as much nitrate as the calcium nitrate, so it wasn’t as effective. Potassium chloride was ineffective.
One reasonable postulate is that nitrate is reduced to NO (nitric oxide) by nitrate reductase and NO is a gaseous effector molecule in plants. That suggestion is very old, but may be right. Nitrate is also of course used as a source of N for plants and may simply signal abundance of N which means it is OK to start growing. When nitrate is pumped into cells it increases their osmotic pressure which may help swell them to split the achene. Other ions like Cl- are excluded. Sulfate may be taken up but calcium sulfate is insoluble and I tried a reasonable level of magnesium sulfate in the Hoagland’s macronutrients.
I used vermiculite as an “inert” medium, but of course it is not. It binds some of the metal ions, and calcium may cause it to release others. We should actually do tests with other kinds of supports such as perlite. It is hard to find something really inert, and not fermentable. With non-sterile seeds, paper towels get moldy. Peat moss is acidic and also binds metals pretty tightly. It also takes up borate which may be another important factor.
So there’s still lots of opportunity to tinker with this method to optimize.
The NO hypothesis is a good bet. It is known that NO is required for other abcissic acid mediated processes, see
Thanks to Larry and Don. It will be interesting to see if adding the calcium nitrate already in the period of warm stratification will give the same results. Thanks to Joe for your welcome. I will come back with the results hopefully already in Mach.
I proceeded with the calcium nitrate plus vermiculite, bagging up one batch(earliest harvested hips-all dated before 8/15/11) on Nov 8, the next batch several days later, and then the last batch about two weeks after that. One cup of dry vermiculite to one half cup of prepared solution seemed to be the correct/desired dampness–I think I got the proportions backwards on the above first question. SO–last night I decided to check and see if maybe there might be any movement towards sprouting among the first early picked batch-and could not believe how many little sprouts were awaiting me. I haven’t potted them yet-will do tomorrow-had to get the potting mix, pots, trays, etc., out and ready. Have 46 pots ready to go and am hoping that will be enough. I don’t think I have ever had that many ‘first’ seedlings before.
The proportion I used was by weight, because it is hard to get a uniform dry measure of vermiculite I found. But whatever works is OK.
One alteration you may want to consider based on my more recent experience. For some CVs it is clear that the dosage I used (10 mM of calcium nitrate was a bit too high. It still is the best for the CV I had tested first, as is confirmed by a repeat the next year, but for some others about half as much is optimal.
I’ve just started the full tabulation for the next newsletter. I have quite a few CVs, and a few species tested. So I think it will be interesting to see how the results actually come out.
Time will tell. I already have given them all the same dose. I am aware that this was/is still experimental and now hope that a few crosses that I have that I want to have at least a few resultant seedlings, I probably should have divided into two batches. One treated, one not. But I am sure going to find out which varietals respond to this dosage. The seed production was very good this year and I have about 1000 extra seeds–that is what prompted me to ‘experiment’.
I did pot up all the early germinations-there were 70 sproutlings from 400 seeds. Two were rotted, but I doubt that it was from just length of time, because they were only in the fridge for one month-shy by two days. What was really amazing is how totally desolved the ‘suture’ zone was. So much so that even with a tiny portion of radicle emerging, it was easy to split both the achene wall and testa with fingernails-usually exerting minimal to no pressure. This brought the question to mind about the Country Dancer achenes: Where any of these seedlings ‘grown on’ and brought to maturity after being counted? Where there instances of seedlings that sprouted but clearly where dead, and how were they accounted for?
I will check more often, probably weekly, since many radicle tips were apparent, but I did not separate out anything with less than a quarter inch ‘root’. Growth will probably be slow this week, since this batch of seeds are now in the shade of the patio on the north side-and temps were down to 33F-38F each night this past week. Not a whole lot different than the fridge.
In the first year test, I planted a very large # of C.D., known then only as “dorm pink”. I always lose a significant fraction of seedlings with radical emerged. Sometimes half. But in most instances, the things I counted as germinated in my monthly measures were at least 1/4 inch of root and many were a full inch or more seedling. When I used the treatment on more valuable materials of course I kept and grew out all I could. I did not notice that survival was lesser in the nitrate vs water treatments. But I didn’t really do serious counting, just impressions. For a number of treatments this year my germ rate is >50% but I’m less than half through tabulating other CVs and treatments. Some may be considerably lower
Sorry for the anonymous user posting.Not sure why it showed that way. I just found that feature of the post lists- very good.
BTW, I seem to be logged on a full day after having left. So if there is a time-out it is long.
I put my seeds into moistened paper towels when I give them cold treatment. This year I used 1 teaspoon of 10 mM Calcium Nitrate solution instead of water for each folded over paper towel. I started cold treatment on Nov 1st and had my first germinations by Dec 3rd. Last year it took 6 or 7 weeks befor the first germinations without the solution. I used it on some Smoothie OP seeds and the first germinations are happening in just 3 weeks. So far it’s only been 6 weeks of cold treatment and I have already planted close to 100 seeds and have 25 seedlings that have come up. I really think the calcium nitrate has made a big difference in how fast the seeds are germinating.
So far I have 28% of the seeds I took out of the fridge on Dec. 5, that have germinated and they look really good. I applied the calcium nitrate on Nov. 8 and am checking them weekly. So far 186 seedlings. Next week will be a big seedling week from the looks of all the radicles emerging. Will be removing another batch from the fridge next week. This looks like it will really speed up the germination to a much shorter ‘season’. But I will also run out of room with all those germinations in such a short time. Won’t have the opportunity to cull much without the germinations running over a much longer period.
Your results sound very promising! Is there an easy formula using easy to obtain materials to reproduce a 5 mM solution? I have some seeds that I would like to experiment with.