Sulfuric acid seed treatment


#1

I am thinking about experimenting with sulfuric acid treatment of Cornus mas seeds.

I have never done this with any seed before. Does it remove the need for both scarification AND stratification or is that seed dependent?

From what I have read Cornus mas seeds need about five months warm stratification followed by three months cold. Supposedly the five-month warm stratification allows for microorganisms to degrade the surface of the seed making it penetrable to water. The acid is supposed to replace this part of the procedure (if I understand it correctly). Would I then just cold stratify the seeds or is that still necessary?

Thanks,

Matt


#2

It does not eliminate stratification requirements to any seeds. At least cold stratification. I never heard of a seed needing warm stratification. In the case of Rubus seeds if you didn’t use acid, it will sprout in 2 years. But it may only need 5 months, getting 5 months the first season would be hard, so it usually sprouts the 2nd year.
Rubus is tough as the seeds also need light to sprout so cannot be buried.
Also I have grown Cornus mas seedlings and they need 6 years to fruit on average, a minimum. I have a couple seedlings that may take 8 years? Three did fruit in 4 years, the rest out of 14 of them fruited in 6 years, except for two. Fruiting is sparse the first few years.
The two unfruited trees are now 7 tears old. Hopefully next year.


#3

The acid could help with scarification but it won’t reduce the need for stratification. What concentration of Sulfuric acid are you thinking about using? Concentrated sulfuric acid would destroy the seeds. You’re going to need to use a diluted acid. I have worked with concentrated sulfuric acid and it’s not something you want to handle without PPE and reviewing the SDS.

Several suggestions:

I would join the Facebook group for Cornelian Cherries (cornus mas). People there are starting cornus mas from seeds for rootstock or breeding.

Why are you starting cornus mas from seeds? If your wanting rootstock or just to make a hedge for decorative use this is a reasonable approach. If your growing it for fruit you really need grafted trees. It really takes too long to grow them from seeds and the fruit quality isn’t as good as you get from grafted trees. I planted grafted trees and it took 4 yrs to get a small crop of fruit.

I have “Plant Propagation” by Alan Toogood. For cornus mas propagation it recommends:

  1. Store fruit in warm water for several days and remove seeds.
  2. Then store cleaned seeds in moist sand for 60 days in a refrigerator.
  3. Then sow into containers and germinate at 60-70F.
  4. If germination fails chill again for two months and try to germinate again or leave outside over the Winter and germinate in the Spring.

#4

From …
"Seeds of woody plants in the United States "


#5

That looks like good info. Cornus mas though is a lot different than the other dogwoods.
Here I stratify seeds in an unheated garage over winter. Works well and I can keep moist and no soil in the fridge! My only beef with the article is lack of info on sulfuric acid concentration. I also have Gibberellic acid but I use it for other reasons (larger grapes, more fruit on tomatoes).
I have found with stone fruit if you put the seed in moist paper towel for a month in the fridge the shell becomes brittle and is easy to break. The seed is re wrapped in moist paper towel and kept moist in the fridge till it germinates, than is placed in soil.


#6

Info on acid treatment ( concentration from…
"Seeds of woody plants in the United States "


#7

So your unheated garage would be your cold stratification? And that’s all you do to the seeds? Or are they in your garage long enough to experience a swing in temperatures (60s trough 30s)?

I’m trying to grow a bunch of rootstock for future grafting but thanks to the Facebook group listed above I now know of a nursery that sells rootstock. Given that I now have seeds I may pursue both options.

From a couple of different sources I have found online it seems like warm stratification and scarification are the same thing or rather they perform the same function. They both allow for the impermeable seed coat to be degraded and warm stratification was probably in practice long before someone tried dropping seeds in acid to see what happened. When scarification became more common the term stratification became universally understood as cold stratification. Probably.

Thanks for all the replies everyone!


#8

Yeah it gets down to 25. Really you need chill hours, so anything under 40 counts.
It is warm at first till winter hits, and then warmer in the spring. I usually put them outside on my porch (overhead protection) in March. So once they can germinate from warmer temps, they are outside.

I agree, I never heard of it, but that is my ignorance. I have now thanks for posting about this.

Yes, I never knew of warm, just assumed cold. I know better now.

Oh I use battery acid btw as it is sold at any auto parts store. It is only 30% and safer to work with. Leave in 3 times longer than you would in 95% sulfuric acid.


#9

Sounds good…I have a half dozen 5 year old cornus mas…maybe I’ll get a fruit or two next year.


#10

@Drew51
For cold stratification , I was taught …
,it’s time below 45deg F.
But above 32deg F .
Below 32 the clock stops.
And can damage some seed to freeze when wet.
( pawpaw for example.)
Others not so much


#11

Yeah I was doing Rubus seed. It does not mind. I get plenty enough chill. Surprised about pawpaw as they are native here.