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MagicalMedic

No growth on mycelium from spore inoculation

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A friend down the coast is trying to grow edibles from spores and made his own potato dextrose agar (boiled potato broth with some honey added) dishes. He inoculated agar dishes with one species weeks ago, and then tried another different species on dishes made from the same agar a week or so ago. No growth whatsoever has been observed on any of the dishes [with the exception of the germination of a single mold spore contam on one dish that grew well). Could it possible to make an agar with both potato starch and a little honey that just can't support mycelium?

He additionally made a spore syringe from the remains of a dirty print, hoping to put this to agar to isolate clean mycelial sample at a later stage, but observed a few days later that little white fuzzy dots were visible in the syringe, despite the lack of nutrients in the water. Could this be germinated mushroom spores or is contam more likey?

cheers

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Honey is not dextrose, rather fructose and glucose...however i think that mix should support growth. How much did you use, maybe the agar is too "rich". Is there any glossy/clear growth on the surface...cld be bacterial contam.

I believe spores can germinate in the syringe despite no additional nutes only way to find out... inoculate some substrate. wait and see... :rolleyes:

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I thought this mix should work too. He took the recipe from a good source at the shroomery, almost certain it's not too rich. One slant I had a look at definitely had bacterial contam - slimy looking clear growth that clouded the agar, but the others all look fine.

Inoculating some spawn with the syringe might be a good idea as I'm not sure how long germinated spores will last without nutrients (if they are germinated spores).

I thought honey had D-glucose = dextrose?

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What temperature is he keeping them at?

Low temperature I think - averaging about 22 degrees subject to daily fluctuations. I know this isn't ideal but he thought it'd just slow growth. Can it entirely prevent germination?

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nah 22C should be fine for mycelial growth. I've had very retarded progress at around 14-16C where it has taken a month for any sort of progress to be visible.

It's possible your spores are no longer viable?

I see no reason why your medium wouldn't support life but if that's the only variable maybe you should try something different?

oh and i didn't notice your second question...

if you have 100% spores in a syringe in water they won't germinate. However most amateur mycologists aren't able to seperate the spores from the gills, so i'd guess a dirty sport print would have a lot of gill remnants that the spores could use as food to germinate from.

Hope some of that random information helps :)

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I'm assuming he sterilized the agar mix in a pressure cooker or by doing a series of cooks in a microwave, yeah? Its easy to over-cook an agar mix and have

the sugars caramelise as to be unusable to the mycelium- it then actually can retard or deter growth. For 500ml, about 15min in a PC once its reached pressure is about right.

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How experienced is your friend at growing edibles? first time?

Maybe he should try a Karo Liquid Culture as it is super easy and it will get him started on the grow. Once he knows the spores are viable he can start experimenting with the agar.

Make sure you use a PC

Good luck. Some don't get it first attempt. If your friend keeps at it im sure he will succeed

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Cheers for the info, yeah it's first time. Bizarrely after more than a month some of the spores from one variety germinated and are now growing mycelium (albeit slowly). A second attempt with a different variety yielded faster germination (about a week)and faster growth. The agar was all sterilised, only one or two obviously risky containers contaminated. I think a different agar mix is in order.

Is it a problem sterilising the agar dishes / containers when they're already poured? This seems the best way to avoid contam, rather than pouring it out after you've sterilised - is the cooking time very quick in the case though to avoid caramelisation?

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If you keep the PC time under 45 mins you should be fine. I like to PC it for 30 mins.

I do both in terms of plate pour alternatives. I tend to mix 1L of agar and for 16 small PP take away containers, this is far too much. So i'll pour the 16, seal them, place them carefully in the PC around the now half full flask, 'sealed' with foil. PC for 30 mins once the jiggler starts doing its thing.

The agar in the flask will store for at least a month. I just put it back over a low flame when i want to pour some more dishes (into empty previously PCd containers)

Basically it's easy to throw a few empty plates in amongst a substrate cook. Hard to keep poured plates level amongst substrate bags.

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If you keep the PC time under 45 mins you should be fine. I like to PC it for 30 mins.

I do both in terms of plate pour alternatives. I tend to mix 1L of agar and for 16 small PP take away containers, this is far too much. So i'll pour the 16, seal them, place them carefully in the PC around the now half full flask, 'sealed' with foil. PC for 30 mins once the jiggler starts doing its thing.

The agar in the flask will store for at least a month. I just put it back over a low flame when i want to pour some more dishes (into empty previously PCd containers)

Basically it's easy to throw a few empty plates in amongst a substrate cook. Hard to keep poured plates level amongst substrate bags.

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Malt dextrose is best ;)

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I've been having the same problem.

I've streaked some plates with viable button mushroo spores and no go. I've also tried to clean up some wild myc using agar but conatms grow before the myc.

I've had success with an agar wedge someone sent me. The wedge was dry and in bad condition but when i put it on agar it did pretty well.

I have had success with wild mycellium though. I've dunked it in bleach/vinegar solutiion and then gone to liquid culture. Once the mycelium has grown a bit ive gone back to my agar and the myc has done really well....solid growth.

I've been using PDA. I havent been using dextrose though ive been using corn syrup. I'm going to try dextrose and follow the recipe exactly.

The only thing im thinking is that my agar is too dry perhaps. I using one teaspoon of thai agar to 1 cup of water

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