Trouble with spawn drying out before jars fully colonise..

[MagicalMedic]

Has anyone else had trouble with spawn drying out while the mycelium is still colonising the medium in jars? I've got WBS jars that were doing well but then I noticed black patches forming on the outside edge of the mycelium, followed by growth stopping. On removing the WBS (mostly colonised) it was very hard and crumbly and I realised that growth had probably stopped because it'd dried out so much. Is this a common problem if you've got large filters on the jars and you're incubating, and could you help it along by injecting more sterile water? This has happened in the past, the jars had been colonising for a few weeks.

It also lead me to wonder how necessary filters are, if you can grow shitake in large sealed bags until the sawdust is fully colonised, for example, does myclium really need gas exchange to colonise - or is it different between species?

Edited April 15, 2012 by MagicalMedic

[El Presidente Hillbillios]

Sealed bags do breathe a little bit thought that actual plastic.

How have you made the filters in the lids? and how big are the jars?

[obtuse]

i dont bother with filters on my jars. if find its too much hassle. I seal my jars, and that keeps in the moisture, and keeps out nasties. I have found in most cases you can keep jars for a while using this method.

i have experimented with filters, but it always seems to end bad.

you could use sterile water to attempt to rehydrate the WBS, but i think once the seed has dried out the damage is done.

How do you prepare you WBS. I soak mine for about two days, then drain for a day. Pressure cooking evaporates some of the moisture from the jars, but once sealed they work brilliantly.

I use the approx. 500 ml jars that you buy tomato paste in. are your jars bigger or smaller. It means i cant do much in bulk, but i only have a small pressure cooker.

Hope that helps,

Cheers, Ob.

[Distracted]

I use filters on my jars, never had a problem with grains drying out unless I didn't prep the grain properly.

Do you keep your jars in an area with a high wind flow? like a fan, air conditioner or open window? The extra flow of area of a fan has been known to dry out jars.

Hope that helps...

[Sallubrious]

What sort of filters are you using.

Micropore tape and tyvec will fail a lot more often than cheap shit poly fill.

You have your location as temperate NSW with no frost so they probably won't need incubation until the cold weather really sets in. Mycelium generates it own heat so most of the time incubation is not needed at all and can be counter productive. As soon as the temp gets over about 26 deg the contaminants gain the upper hand and will start to win the battle, over 28 deg and you will lose more than you get colonised.

The type of incubator is important too, a heat pad or heat mat will dry the jars out where a tub in tub at the same temp won't have that drying effect as much.

The best advice when starting out is to do control jars that get cooked and don't get innoculated, that way you can determine if you have sterilised the grain properly.

If the control jar/s contaminate you know you have to fix that stage of the process and you can eliminate any other causes of contamination.

Only shake your jars once during colonisation at about 50 - 70 % colonisation. Too much shaking will set back the growth and increase the chance of contamination. Another shake when they 100% colonised the night before you spawn is handy to loosen the grains as it will give the mycelium time to recover and quickly start growing again by the time you spawn.

[MagicalMedic]

Thanks for the detailed replies! I am using a variety of jars - the smaller than 300ml ones colonised easily, those closer to or bigger than 400ml didn't colonise completely. The grain was soaked for one day and drained for a few hours. I am using material with very small pore size for filters (pore size is a tiny fraction of that of tyvek), and the filters are about 2x2cm - possibly unecessarily large. There is very little airflow in the incubator, it's a dual tub setup - but it has been warm, around 26 degrees.

I haven't actually had any contamination this time around, I think the black spots were just dead or rotting material, as there was no evidence of it spreading or being fuzzy.

I find it odd that there is still seemingly a fair bit of uncertainty as to whether filters are necessary or worth the risk.. Without filters your risk of contamination is so much lower, I'd only use them if I was certain they were necessary.

Changing up the approack a bit sounds like a good option - soak the seed for longer and drain it better, innoc a bunch and leave some at room temp separate, and some without filters, to see if they colonise as fast. If colonisation times aren't too different, do away with filters.

Edit: I hadn't considered the fact that palstic bags breath. Do you think it'd be enough to make a measurable / significant difference to say, colonisation rate in a truly sealed enviroment? The simplicity of directly innoculating bulk sub in sterile bags has always been appealing but I've not read much about it. I noticed in the mushroom growing course mentioned elsewhere in the forums recently, they used sawdust & straw bags sterilised and directly innocd for successful shitake. Would be much easier than the sometimes catastophic transfer of grain spawn to bulk sub.

Edited April 16, 2012 by MagicalMedic

[migraineur]

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They last for years and years and they fit mason jars perfectly. You can find those jars here: http://redbacktrading.com.au/index1.html