thoughts on germination media

I realize that many on this forum use no medium. But I’ve had my best luck with soiless mixtures. I may be wrong, but I feel like they help maintain more consistent moisture, and wonder if they might help with leaching out germination inhibitors. I also have heard (right or wrong) that peat has natural mold inhibitors…

A few other thoughts/observations…
-Joan Monteith once sent me some seeds – near species hybrids – which she had in a mixture including vermiculite and charcoal. She had begun stratification (a month or two), but we both assumed the seeds would probably require a full season of stratification. They were, in fact, germinating by the time I got them. I assumed the charcoal was helping to remove inhibitors as these were among the quickest germinating rose seeds I have sprouted. I assume she used activated charcoal – a purification product.

-Evidently smoke has been hypothesized to help germination. I wonder if some forms of charcoal might maintain compounds similar to smoke.

-Peat is acidic. I believe that charcoal (or at least ash) is generally alkaline, having as it does, potash/lye in it. Mixed in the right ratio, they might theoretically create a relatively neutral blend.

-there have been recent studies pertaining to “black gold agriculture” which utilizes biochar to enhance plants’ performance…

At any rate, I’m wondering if a mix using some peat and some charcoal might have any benefits to germination. Purely speculation, and probably a lot of humbug, but wondered if those more educated on the subject had any thoughts…

I don’t anticipate germinations due to age of seeds anyway, but went ahead and used an approx. 10:1 peat / charcoal (from unconsumed burnt wood in fireplace) blend in a mix for germinating seeds. Probably a dumb idea, but…


Very interesting, but if I’m understanding the synopsis correctly, why aren’t more hybridizers using charcoal?? I only have very limited anecdotal evidence of it helping, but in view of that paper…

I wonder if your using peat does not defeat the use of charcoal as the charcoal will be clogged up with chemicals from the peat.

I set my seeds up in moist vermiculite for stratification and germination.

I used sand.

I have some activated charcoal in the lab (it is ground very fine and neutralized for pH) and should try it. That sounds like a great idea. I have it for when we grow orchids especially in tissue culture to bind up the secondary metabolites they generate and exude into the media and which eventually limits plant growth. I should try the charcoal mixed separately with peat and vermiculite and sand for comparison.

I typically use just straight peat for stratification. The moisture can be held just right and having just peat makes it easier for me to see the radicals coming out for germinating seeds in the clear baggies. I check the baggies usually weekly and pot up what has germinated. It seems like the peat suppresses some of the nasty fungi, but there still what seems to be a good fungus that works on the pericarp. Having no medium and a little bit of water in the baggies hasn’t worked well for me with I think bacteria issues. Maybe I have too much water in there. Paper towels have been challenging for me for them degrading and root hairs getting entangled if they go too long before potting. Vermiculite has been okay, but I keep going back to peat.

I used moist Perlite this year. It happened to be Miracle-Gro Perlite which has a small nutrient charge. For large quantities of seed per cross I mixed the seeds with Perlite in the baggies. For smaller quantities, such as less than 150 seeds, I sealed the seeds in a nylon mesh teabag with their label. Then I immersed the teabags in wet perlite in a sealed container. After one month of warm stratification, I removed the teabags from the perlite and leached them under running cold water for at least several hours, overnight for most. After another two weeks of warm stratification I sowed the seeds in flats of germination media, covering them with vermiculite, and put the seedling flats into a just-above-freezing building. I’m keeping out one tray of R. nitida crosses to get a full two month warm stratification as recommended by Paul Olsen and others. Indeed as I was sowing all my seeds many of the seeds were quite black, which I think is a good sign that the warm stratification was softening the pericarp. Most of the R. nitida seeds were still shiny brown, which seemed like additional evidence that they should get more warm stratification.

So I really like the idea of the activated charcoal in some sort of oxygenated leaching. If the water was kept oxygenated, could you soak for longer without harming the seeds? So what if you set up a ‘bubbler’ to oxygenate the water, had a bunch of activated charcoal in the water, and let the seeds soak for 48 hours in that?

One of my customers once shared with me that she had gotten Iris seeds to germinate readily. I can’t remember exactly, but maybe sulfuric acid treatment followed by (this part I’m pretty sure) 24 hours under running water. Iris seeds really need the leaching.

It seems like if we got this system right we could achieve almost instant germination…just soften the pericarp and remove all the germination inhibitors.

Ditto that, David. I had nothing to speak of for my efforts the years I used no media, and the year I used paper. Admittedly, I had very limited seeds, so that affirmation isn’t statistically meaningful in view of the ridiculous range of results I get anyway.

I was fearing that using straight peat (as I have in the past) might be foolish in view of pH issues, but you make me breathe a little easier about my M.O… I have not had good results in a while, but largely due to my inclinations to experiment as well as other distractions in life I think. The powdered charcoal (at least the stuff I’m using) in the mix really darkens it and should make the radicals really stand out. I was a little disconcerted at the extent of pigmentation, and worried I might have overdone the char.

Henry, I take your point. (I figured there would be some logical error to my thinking! I was rather wondering about the Ca(NO3) being absorbed into the charcoal – didn’t occur to me I was potentially defeating the absorption…)

I would assume that activated charcoal would be cleaned of any “smoke” activators, should such exist. I wonder if hardwood charcoal (of the sort in high-end smoker/grill applications, i.e. not the processed briquets) might have merit? One would have to carefully check for pH, of course. I used unconsumed hardwood char from my (evidently inefficiently-burning) fireplace. (I won’t tell my wife which kitchen appliance I used to pulverise it. :slight_smile: )

Joe, based on some of your earlier posts, I think you and I are kindred spirits. :slight_smile:

I soaked some dried hips in a very diluted blend having about 5 parts H2O2 to one part cider vinegar. Presumably, I had some dilute peroxyacetic acid (which is used for sterilizing in the food industry) in my very oxygenated solution. I probably killed the seeds. (Not the proper way to conduct an experiment, Philip! LOL)

I always feel odd on this topic.
I just use what I use in pots? 1:1:1 coconut coir, vermiculite, compost (or potting soil depending what i have bags of lying around). I dont stratify either, straight into the mix after being harvested. Im lazy and dont want to fuss eith them much.

This approach for me hasnt been an issue with moderns/minis, fairly high germination (probably because the seeds never get dry and i never have to deal with frost or freezing). Unsure about species and ogr roses though, have added a number of those this year so will see how things go with that but theres a lot of “never seen germinate in the first year” reports so will be interesting/new to me.