Agar

[john]

I am starting out with shroom growing. I see a lot of recipes for
agar. I have mycelium  growing in straight agar. Should I use a mix?

When peroxide is used is that just for sterilizing or is it included in the agar mix. 

sorry to be so ignorant.

john S / Nimshie29

[Darklight]

13 hours ago, john said:

I am starting out with shroom growing. I see a lot of recipes for

agar. I have mycelium  growing in straight agar. Should I use a mix?

When peroxide is used is that just for sterilizing or is it included in the agar mix. 

sorry to be so ignorant.

john S / Nimshie29

 

 

Hi john

 

Welcome to the wonderful, frustrating, fun world of growing mushrooms

 

The agar question is a helluva lot to unpack. There are a bazillion recipes for 'agar' ( which is really only a generic word for whatever gelling agent is used to solidify the semisolid stuff in a petri dish, but the common use now includes whatever else is in the mix ). Confusing as fuck IMO

 

Most people just use what's convenient for them that works, hence all the different agar types. Some types are specific to species, some are general, some used to deter competitors to get a cleaner culture etc

 

Are you using only agar and water- your OP refers to straight agar- or is there other stuff in there, malt extract, dog food, vegemite, lime etc

 

H2O2 ( hydrogen peroxide ) kills spore of bacteria and fungi without killing most mycelia- up to a point ( it can be overloaded, degrades if you keep the agar plates for too long, and shouldn't be added until your agar has cooled to the point where you can hold the container by hand )

 

3% hydrogen peroxide is usually added 2-8ml/L when your agar has cooled and is ready for pouring. It can negate the requirement for pressure cooking your agar and is also handy if you don't have a sterile cabinet or still air box to work in. I've poured H2O2 agar in the open in my kitchen and had good success with it. I usually carry some plates of it with me if I'm taking samples from mushrooms I find on bushwalks

 

You don't need H2O2 added to agar, but there are some situations which it really helps. Some species don't like it much and some take a while to establish on it

 

Hope that clears things up. Good luck!

 

[john]

Many thanks for the clear response. I just prepared some agar from a health food shop boiled with water - nothing else.

I will try H2O2 as suggested in the mix next go. Mine have started to grow but are moving very slowly after 2 weeks. Maybe I 'm

used to rapid growth in the tropics.

[Darklight]

2 minutes ago, john said:

Many thanks for the clear response. I just prepared some agar from a health food shop boiled with water - nothing else.

I will try H2O2 as suggested in the mix next go. Mine have started to grow but are moving very slowly after 2 weeks. Maybe I 'm

used to rapid growth in the tropics.

 

K- so you have made what's called water agar

 

It's not really nutritious at all and any growth you get could be resulting from residual nutrients in whatever it was you inoculated it with. That could be why growth is slow

 

A general purpose agar is something like Malt Extract agar

 

There are a million recipes for Malt Extract agar, often just varying the amounts. One that's worked for me for a variety of species is:

 

20g/L light malt extract ( brewing supply shops sell it )

100mg/L garden lime ( Bunnings )

100mg/L potassium dihydrogen orthophosphate ( some people omit this )

20g/L agar ( health food shops )

 

A litre of agar is heaps! Like, about 40 standard petri dishes worth. So work out how much you actually need and change amounts accordingly

 

If you want to add 3% hydrogen peroxide at 2-8ml/L, do that after you have cooked your agar and the container is at a temperature which can be held comfortably in your hand

 

Malt Extract Agar is really nutritious. Lots of species like it- so do lots of contaminants.

 

Not all species are happy with you adding hydrogen peroxide, but many will overcome their distaste for it and grow after a couple of weeks

 

Good luck!

[rottenjonny]

my recipe is 

 

1g light malt  - from the home brew shop

1g Agar - from the asian grocer

50ml water - from the tap

 

Never had any problems with oysters etc.

 

I use a method called pasty plates which uses little containers like you get from the chinese restaurant for sauce. 

[john]

10 hours ago, Darklight said:

 

K- so you have made what's called water agar

 

It's not really nutritious at all and any growth you get could be resulting from residual nutrients in whatever it was you inoculated it with. That could be why growth is slow

 

A general purpose agar is something like Malt Extract agar

 

There are a million recipes for Malt Extract agar, often just varying the amounts. One that's worked for me for a variety of species is:

 

20g/L light malt extract ( brewing supply shops sell it )

100mg/L garden lime ( Bunnings )

100mg/L potassium dihydrogen orthophosphate ( some people omit this )

20g/L agar ( health food shops )

 

A litre of agar is heaps! Like, about 40 standard petri dishes worth. So work out how much you actually need and change amounts accordingly

 

If you want to add 3% hydrogen peroxide at 2-8ml/L, do that after you have cooked your agar and the container is at a temperature which can be held comfortably in your hand

 

Malt Extract Agar is really nutritious. Lots of species like it- so do lots of contaminants.

 

Not all species are happy with you adding hydrogen peroxide, but many will overcome their distaste for it and grow after a couple of weeks

 

Good luck!

Thanks again. May be I can transfer the dishes that have started into a new agar mix. I am collecting some spores from a fried this morning so happy I got your recipe.

[john]

Just now, john said:

Thanks again. May be I can transfer the dishes that have started into a new agar mix. I am collecting some spores from a fried this morning so happy I got your recipe.

 

[Darklight]

Sounds good

 

If you are starting from spores though, remember you can't add hydrogen peroxide to your media. Hydrogen peroxide kills spores

 

[Northerner]

On 30/12/2020 at 6:21 AM, rottenjonny said:

my recipe is 

 

1g light malt  - from the home brew shop

1g Agar - from the asian grocer

50ml water - from the tap

 

Never had any problems with oysters etc.

 

I use a method called pasty plates which uses little containers like you get from the chinese restaurant for sauce. 

Yeah that's the same recipe I use, Except I cook up enough for 20 plates at a time and use china brand petri dishes. Been thinking about the pasty plates, seen the tek, just already have a big box of petri dishes to use.