I saw a product today at my local garden center which is supposed to enhance germination.
It is made by a brand that focuses more on cannabis growing, but I was wondering if this might be useful for enhancing germination in rose seeds too?
The product is sold as a kit with ten cocopeat plugs and a mini greenhouse. They say to dilute the product 50/50 with water and soak the plugs with this solution, then close the greenhouse and let the seedbooster work it’s magic.
I was thinking of trying this after stratification.
Any thoughts on whether these ingredients might help with rose seed germination?
Thank you @lee_hull !
It seems like the calcium nitrate solution can give really good results in the right doses! Very interesting discussion in that thread.
I have some of that stuff as part of the Masterblend fertilizer pack. I had added it to one of my seed batches in the fridge but got zero germinations so far (OP Mme Charles F Worth, in the fridge for 8 weeks now).
The Seedbooster has different nitrates but also phosphoric acid, unfortunately they don’t state the exact strength of what’s in the bottle on the label, aside from the npk.
I have about 50 seeds of OP Honorine de Brabant that will be done stratifying in about a week. Those didn’t get treated with anything but a quick peroxide bath and then plain water.
I might get the Seedbooster and use it on half of them, and the calcium nitrate on the other half once I take them out and see what happens.
The calcium nitrate is meant for use during stratification. I generally use around 35 grams, somewhat more than an ounce, of the moistened vermiculite per sandwich bag with up to 100 seeds. IF I have very few seeds of a cross I may use a snack bag with somewhat less of the moistened vermiculite. To avoid crowding of sproutlings, I usually divide large seed quantities into multiple packets of around 50-75 seed per bag. The nitrate, ammonium, phosphate mix is reasonable. I didn’t bother to calculate concentrations in the units I understand (molar, millimolar). I found calcium nitrate the best source of nitrate in my early tests, although potassium and ammonium and magnesium salts also worked well. I avoided sodium because it is too much like salt. Be warned that the phosphoric acid is a problem with calcium because they form calcium phosphate which is insoluble. This will alter the pH somehow but ahead of time it’s hard to say just how in the presence of vermiculite or other potting medium which has buffer action.
I did some quick calculations. The N level in the seedbooster is about 10 mM total, around 8 mM of nitrate, 2 mM of ammonium. Too much ammonium is toxic to many plants. The potassium is around 1 mM and the P is somewhat lower than that. Net effect of those latter two is a pH buffer near 6.5, which is good. The ammonium counterbalances 2 m M of the nitric, leaving 6 mM to be accounted for pH balancing, so either calcium or or (more) potassium would need to be added somehow. I would guess that it was really composed of 3 mM calcium nitrate Ca(NO3)2 and 2 mM ammonium nitrate.
That is really interesting @LarryD , thank you very much for such a detailed reply!
I ended up buying the Seedbooster today.
I have some calcium nitrate, I could try adding a little of that to the solution. But you mention this might be incompatible with the phosphoric acid, so perhaps it’s best if I don’t try adding to their formula?
I’m still new at all of this, and only working with a small number of seeds this year, so anything I can do to increase germination will help me get the most out of what I have. I’m reading all the forum threads to learn from everyone’s tips and experiences.
I really appreciate you taking the time to look into the composition, thanks again.
I did an experiment on a large batch of OP Carefree Beauty seeds with a liquid suspension containing 8% N, 8% Ca and .5% Mg (diluted appropriately – roughly 3.5 cc/litre per my notes) with mixed results.
In my admittedly statistically insignificant experiment, I got overall slightly quicker germinations within a smaller window of time from the seeds having the solution than the others, but the overall long-term germination was slightly poorer. I wondered if the supplemental nitrogen might be helping microbes attack weaker seeds in the treated batches?
As I say, I consider that experiment relatively meaningless without recreating it multiple times to account for the probability of potential anomalies, but thought I might share for those interested in exploring such.