A simple and easily followed but approximate (note the approximate here) formulation for 5mM would be 1/2-3/4 teaspoon of calcium nitrate dissolved into one gal of water. If using with vermiculite, wet to where all liquid is readily absorbed (which is approx 1 cup vermiculite to 1/2 cup liquid solution-I’m sure some vermiculite will vary, so this is also approx.), or use with paper towel as per Paul G’s description.
This is just a preliminary observation but I have noticed approx. 5 seedlings with emerging roots that were in differing levels of “root turning brown”. In the first week two seedlings with roots well grown out, (maybe 1") were completely brown and appeared ‘rotted’. This may be that for this variety the 10mM solution was to strong. In the second week I noticed 3 roots that had only the very tip turning brown- and these are doing well now that they are planted. I don’t know how long the first two were germinated before I checked for any seedlings, but in the second week they could only have been germinated for a max. of one week and left sitting in the solution with vermiculite. This is purely conjecture, but my fridge was not freezing, and now that I have the seeds outside, the temps. have been between lows of 33F and highs of around 55F for the last 10 days. It is really interesting to see so many of one variety germinate so fast, all at once. It will be interesting to see Larry Davis’ complete tabulations when this season’s crop is germinated completely.
I missed out on the original article by one issue, and it doesn’t show up in the archives (maybe it came on the DVD…I’ll check that when I get back to my PC.) I really look forward to the upcoming article.
I found calcium nitrate on Amazon: five pounds for under twenty bucks after shipping. I think it’s the same fertilizer-grade stuff, containing 1% ammonium nitrate, that Jackie mentioned earlier.
All of my seeds are sown, stratifying in a commercial growing mix. What do you think of the idea of mixing up one teaspoon per gallon fertilizer-grade calcium nitrate and watering down my seed flats about one month before pulling them out of cold stratification? Probably wouldn’t hurt anything, I conjecture. Worst case scenario the peat renders the calcium nitrate ineffective. If I have multiple flats of one type of seed I could run a trial, although irregular mouse damage will render all results inconclusive.
If you would like, I can mail you two-three ounces of the calcium nitrate. I bought 50lbs for $12.00. I can use some on the slopes so I didn’t mind having a little extra-but this is a bit much and you need so little. A gal of solution would probably be more than Weeks or Jackson & Perkins could use. With Christmas mail a bit busy, it might take a few days extra, but my guess is that it would work the way you propose-but I would think that if you could devise a means to only dose a percentage of your seeds,the results might be more meaningful for comparison purposes.
I did some further tabulations last evening. It is clear that the 10 mM calcium nitrate speeds germination of most, but not all CVs. Also clear that for many of them the final total is lower with that than it is with 10 mM potassium nitrate. I am working on various refinements but won’t have them for another year. 72 bags of 50-100 seeds in test now. Some with various combinations of ammonium and calcium nitrates. Meantime, I would encourage you to go a bit lower with the calcium nitrate. The worst that can happen is delay of the speed-up. I did try 10 vs 3 vs 1 mM and I think I mentioned somewhere up above that the lower the level, the slower the germination. 1 mM was not much better than just water for the particular CV I was testing. But that may be different for others. Tests are started. I would shoot for something round half a teaspoon/gal. (3 grams) A bit more if your nitrate salt is hydrated. It takes up water easily. Fertilizer grade may contain excess calcium too (from lime). So perhaps 3/4 tsp/gal.
I guess I should explain how to make a two pan balance, and a standard weight for the balance pan, like a penny or dime. Or an old-fashioned letter weighing one that works in fourths of oz, or less. Next newsletter.
Species and CV do differ. For instance with R glutinosa I got really a lot of seedlings with calcium, less with potassium and very few with zero of nitrate. Not just a time thing, but a change of overall total. That contrasts with the effect mentioned above with some complex CVs. See above for R pomifera effect.
I don’t think the nitrate hurts seedlings, in most cases. I know in some instances they have been exposed to it for more than a month after germinating. I have very few, maybe 1 % of seedlings die while in the vermiculite. In some cases the achenes turn black, but the seedlings are happy. I even dried (unintentionally) a batch of R. multiflora with the nitrate. When I rewetted a month later, the calcium nitrate treated came up fast and more abundant than the potassium or water. These seeds had been harvested about Jan 1 after freezing repeatedly on the bush so overall germination was not very good in any treatment. But even the very high osmolarity of concentrated salt did not kill them.
Larry, the results people are reporting using your method of treatment with nitrate are pretty remarkable.
The differences between the calcium and potassium salts is probably partly explained by their difference in solubility product constant. If I get a chance I’ll dig out my CRC and work up a graph to compare the concentrations of free nitrate ion.
Jackie, I’d take you up on that. I’ll probably need more than a gallon, because my seeds are already sown in seedling flats and I’ll be wetting a much larger volume of soil than those germinating in vermiculite. I’ll have to wet about 12 to 18 standard greenhouse (11" x 22") flats worth of soil about 1.5 inches deep. Still, at about one teaspoon per gallon it shouldn’t take too much.
I’m in no hurry. I don’t really want my roses to start germinating while still in storage. I’m more interested in the possibility of increasing total germ percentage, and possibly getting more uniform germination.
Thank you Jackie and Larry for this information! It looks like you might have something of a breakthrough Larry, for helping to germinate difficult to germinate seeds. I am looking forward to your final results.
This is totally a “thank-you Larry” project. I’m merely jumping the gun in trying it so soon, but I believe Peter Harris tried it also last year. I am happy to try out various germination methods and not scientific enough to come up with anything on my own. So any observations on my part are really just conjecture, always subject to modification.
Thanks for investing so much effort and for sharing the results.
As a matter of curiosity – and I may be interpreting risks and effects incorrectly – I was wondering if anyone has attempted an alternative pre-soak of seeds in a concentrated solution, and then planting up in unadulterated media. I’m wondering if that might do the job of breaking dormancy without strongly tainting the media in which the seed germinates. I have no idea if that might decrease any potential detrimental effects to young plants from salts…
I, alas, am unable to conduct any experiments – still “armchair hybridizing” at the moment – so please forgive me if I appear to be suggesting what others might experiment with for the greater good.
I think Larry and the others are in a way already doing a pre-soak. They’re saturating vermiculite with the solution and stratifying the seeds in that. When the seeds germinate, only then do they pot them into growing media.
Your suggestion, I think, is more relevant to me…I sow my seeds directly into potting soil mix and stratify and germinate them right in the seedling flat. It’s too late for me to try your suggestion this year, as all of my seeds are in the soil already. I’m planning to try saturating my soil with a solution at the same rate as Larry is using for his pre-soak, but I don’t think there will be a problem of too much salt buildup, because the rate is fairly weak as fertilizers go. We’ll see. With the additional factor of peat moss, there is no guarantee that the solution will have any effect at all. I’m gambling that there will at least be no negative effect.
The 10 mM calcium nitrate is a bit more than Hoagland’s solution, but not a lot. So if it is added to a soil that already has some water, even if added to runoff, it won’t be all that high.
Pre-soaking obviously could range from 1 hour to several weeks. The danger of the latter is that things might go anaerobic and that would presumably be bad. What is the optimum time and treatment arrangement in between those two is something that is open for study.
Yes, of course. I would be afraid to soak anything for more than a day or two at any rate. And I suppose getting the correct concentration to start the process without being toxic would be a bit of a trick – and likely variable from one seed to another – but I wondered if one could gauge the effect so as not to adulterate the environment into which the embryo itself emerges. (Or does it matter?)
I’m trying to remember all of the seed treatments that seem to be able to accelerate germination from calcium nitrate to tomato pulp to…
I’m super excited to see what will happen!! I had some cleaned dry seed in the fridge of a Basye’s Legacy seedling, a couple polyanthas, and some other things. I took the seed and divided them in half and put one of each pair in a baggie with vermiculite with 6mM calcium nitrate and the other in vermiculite moistened in water and then put them in a little warmer fridge (9C). THere is a mix of species with pretty strong dormancy and material with much less dormancy (polyanthas) and it’ll be fun to see how they all react.
The intelligence of hindsite never fails to amaze me, as I think about the fact that I should have divided up some of my batches. But I peeked into what will be the next bunch of seedlings that I will plant on Thurs/Fri., and I see that a number of the seeds that I really want to see some results from are starting to germinate. And some of the iffy small batches, possibly somewhat incompatible, or had low fertility pollen, are showing some germination. I did have some second thoughts about my all or nothing give 'em the same treatment actions, but now am not so worried.
First, thanks for the formula, will go with it next season.Until now I always put my seeds in growing mix with low nitrogen content (as commended by all experts). Now it seems that Nitrogen can be very helpfull to support germination. I also found an old study, not on roseseeds but on oat.