Sterilizing Soil & Fungicide for Seeds

[Plantcelot]

Hi There! I will be sowing columnar cactus seeds very soon. It is going to be my first time so I’m really trying to do things in the best way possible. I will be sterilizing everything, even myself ! There is a lot of good info in the forum but I did not find anything about these. My concerns at this moment are two;

1. Sterilizing the soil in the microwave
I will use the following components all sifted and mixed:

50% Miracle-Gro Cactus Potting Mix
25% Perlite
25% Schultz Aquatic Soil

I have read (different places) that the soil should be soaked in distilled water first and then placed in the oven or in the microwave in an open plastic bag. There are a lot of different opinions in the amount of time. My question is about the microwave:

What is the best amount of time (for my soil mix) to do this procedure in the microwave at a high setting?


2. Finding a good fungicide that it is safe for the seeds

I have read that this procedure is very good in order to prevent seed fungus. A diluted amount of fungicide is feed to the seeds/plants everytime they are watered.

I have not used any specific fungicide before (with the exception of the Rootone with fungicide added).

What is a good dilution rate that is very safe for the seeds/seedlings?

Any recommendation of good fungicide products?

[parodias]

I never sterilize my soil. A good well balanced soil mix doesn't need that and many experiments show that fungal germs are introduced by the seeds.

Fungicide .. use any brand Fungicide based on "thiram" It is the only mild fungicide that works properly without inducing germination inhibitions by accidental overdose. I am using "dry etching" ergo I use a small glass test tube with a tiny "knife tip" of fung. powder, put in the seeds, shake the contents and let the seeds roll off onto the soil. The excess powder (if any) remains in the tube and can be used for the next batch of seeds. This way seeds get coated with a thin layer of protective fungicide. It has never failed.
Be very carefull in using other fungicides, many of them are germination inhibitors and/or growth inhibitors even at normal doses ..
FWIW

[iann]

Turn on the microwave for however long it takes to get steam coming off, then a little longer. You are not actually sterilising the soil, that would take more heat for a longer time, more of a "pasteurisation" which will kill the majority of insect eggs, larvae, any existing fungus, and algae. The microwaves themselves are likely to kill many organisms but that would take only a short time. Be careful, this heating is hot enough to soften cheap plastic containers which may collapse. I microwave directly in the pot before sowing the seed.

My only fungal problems come, as Parodias suggests, from dead seeds and chaff. Live seeds seem happy enough, it is such a constrast between a piece of chaff which will become a ball of fluff in days, and a live seed which must have been exposed to exactly the same fungal spores but stays clean. I don't use a fungicide.

Almost all columnar seedlings are vigorous enough that you are unlikely to experience fungal or algal problems.

[Plantcelot]

I’m glad to learn that most columnar seedlings are vigorous, that increases my chances of success!
Waiting for the steam to rise and then a little longer time in the microwave is good advice, thanks I’ll use that method.

I will try to very careful using fungicides, the last thing I want is to harm my future seedlings. I’ll check to see if I could find a fungicide that contains “thiram”. I did a quick fungicide search and found a fungicide from Schultz named Tri-Action Fungicide (Insecticide, Fungicide and Plant food). Sounds convenient but I do not know yet if it contains “thiram” or not. I will keep searching for more info.
Schultz Tri-Action Fungicide


Thanks guys

[iann]

fungicide from Schultz named Tri-Action Fungicide (Insecticide, Fungicide and Plant food)

I don't think you want to go with that!

[Plantcelot]

I guess that means. . . not good!

[Plantcelot]

I was unable to find any products with "thiram" in the US, but . . . I found a product that works with seeds and Seedlings!
It is Physan 20 . I’m going to try it!

Thanks again to all of you for your help

[parodias]

I was unable to find any products with "thiram" in the US, but . . . I found a product that works with seeds and Seedlings!
It is Physan 20 . I’m going to try it!

Thanks again to all of you for your help

From the EXTOXNET info database

quote
Thiram
"Trade and Other Names: Common names include thiram (U.S.), thiuram (Japan), and TMTD (former U.S.S.R.), TMT, and TMTDS. Trade names include AAtack, Arasan, Aules, Fermide 850, Fernasan, FMC 2070, Hexathir, Mercuram, Micropearls, Nomersan, Pomarsol, Puralin, Rezifilm, Rhodiasan Express, Spotrete, Tersan, Thiosan, Thiotex, Thiramad, Thirame, Thiuramin, Thirasan, Tirampa, Tiuramyl, TMTC, TMTD 50 Borches, Trametan, Tuads, and Tulisan.
..."
HTH

[Plantcelot]

I found some information that I think is very interesting!

Hydrogen peroxide has been used successfully to sterilize seeds and also used for other garden problems as well.

The way they use it for seeds is to buy the 3% solution at a pharmacy and use it at full strength for 15-20 minutes to quickly disinfect seeds. Of course there are other variations to the method.

Here is a very interesting link about H. Peroxide:

Hydrogen Peroxide and Horticulture

[Plantcelot]

Thanks parodias

[parodias]

I found some information that I think is very interesting!

Hydrogen peroxide has been used successfully to sterilize seeds and also used for other garden problems as well.

Indeed .. the use or HP has been decribed in horticulture but the article such as the one you describe is clearly written by an amateur who lacks knowledge about the chemistry of Hydrogen peroxide. He claims that "oxygen" is released which in basic speaking is strictly correct. There is one caveat. The fact that HP is such a strong "disinfectant" has a reason. That "oxygen" is not released as an oxygen molecule being O2 but as an oxygen radical being O° this Free oxygen radical desperately tries to find another O° radical to get to the "neutral" state. to do so it is prepared to "oxidize" anything that is available. If that "anything" is a pathogen then that is fine, if it is not then loss could outbalance the gain. I've never used it & BTW mixing HP with other stuff like fertilizers etc is probably a very bad idea due to the very strong oxidative power of HP ..
I just stick to the beaten track with that sort of stuff
just my 2cts

[Plantcelot]

Thanks again parodias, your postings are always very interesting. I appreciate the help


Well I decided to share my findings about Physan 20 and Hydrogen Peroxide because I really found them interesting and there was no previous information about them here. I did find only one thread that mentioned HP but it was too brief to get any real info. Here is it: Seedlings turning white?

I believe that some people will actually be interested in learning (or testing) more about these products in order to have a wider choice of options. I already posted a link for Physan 20, so here is a link for the ones that will like to learn more about Hydrogen Peroxide:

Hydrogen Peroxide on seeds

[parodias]

well it never hurts to bookmark the link you provided .. one never knows if it may come in handy one day .. thnx

[hob]

ok so now you got me playing with google

www.google.co.uk

this one looks interesting .........

http://www.cactuspro.com/article014.en.html

[iann]

LOL. Small world!

That article more or less describes what I do, plus pictures Except I leave the lights on for more hours.