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I know about field capacity, I am just no good at judging it.

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#1 Guest_Mr. Natural #1_*

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Posted 30 August 2007 - 01:43 PM

I rarely get the moisture content of my subs or casings just right.

I wish some one could tell me of a tek that did not involve the squeeze technique of field capacity.

I wish I had a recipe that was measured by weight not volume that went something like this.

1 pound Coir.
1 pound Water.
1 pound Vermiculite.
28 gm. composted cow manure.
28 gm. worm castings.
1 gm. Brewers Yeast
2 gm. Shredded Coconut
48 gm. Coffee grounds
4 gm. Lime

Sterilize the dry vermiculite in the oven in an appropriate container.
Add the water and Coir and lime together in large cooking pot.
Let it set for 10 minuets for the ph to adjust.
Add the rest of the ingredients.
Pasteurize from 160 to 170 or 1 hour.
Then add the sterilized vermiculite.
Then use with out any further adjustment.

I know that these ratios are off
31% = 448 = 1 pound Coir.
31% = 448 = 1 pound water.
31% = 448 = 1 pound vermiculite.
1.94% = 028 = 1 oz. composted cow manure.
1.94% = 028 = 1 oz. worm castings.
0.07% = 001 = 1 gm. Brewers Yeast
0.14% = 002 = 2 gm. Shredded Coconut
3.3% = 048 = 48 gm. Coffee grounds
0.28% = 004 = 4 gm. Lime
  • = 3 pounds and 111 grams
So to narrow down the correct ratios I try to get the Water % / Coir % / Vermiculite % components close to field capacity

Percentages by weight.

Test # 1.
33.33% Coir 10gram.
33.33% Water 10gram.
33.33% Vermiculite 10gram.
Result: Not enough water to fully hydrate the coir. I did not add the vermiculite.

Test # 2.

25% Coir 12.5 gram
50% Water 25 gram
25% Vermiculite 12.5 gram
Result: Hydrated the coir but well below or under what I estimate to be field capacity. I did not add the vermiculite.

Test # 3.

20% Coir 20 gram
60% Water 60 gram
20% Vermiculite 20 gram
Result: Hydrated the coir but still below what I estimate to be below or under field capacity. I did not add the vermiculite.

Test # 4.

10% Coir 10 gram
80% Water 80 gram
10% Vermiculite 10 gram
Result: Hydrated the coir to what I estimate to be well above field capacity. When I added the vermiculite the mixture still was above what I believe to be field capacity.

Test # 5.

15% Coir 15 gram
70% Water 70 gram
15% Vermiculite 15 gram
Result: Hydrated the coir to what I estimate to be above field capacity. When I added the vermiculite the mixture was below or under what I estimate to be field capacity. When I squeezed an amount of the mixture in my hand, I was unable to get any drops of water.

At this point I am not really sure of which way to go.

Is the Test # 4. 10% Coir / 80% Water / 10% Vermiculite really to wet.

Is the Test # 5. 15% Coir / 70% Water / 15% Vermiculite really to dry.

Would someone good at estimating field capacity test the two mixtures and tell me what they think.


#2 python


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Posted 30 August 2007 - 02:03 PM

Let me first say, the definition of field capacity ---- which is the amount of water a substance can hold against the force of gravity

therefore there is no squeezing involved at all --- and i think also, that some people often misuse the term "field capacity" for casing materials etc, that they have squeezed (i.e. making the term "field capacity" incorrect in such cases)

For casing materials -- i often recommend that folks use the notebook method . Design some casing materials (different mixes) and add water to them....measuring all the ingredients...and take notes on what works best -- overtime you will accumulate a vast arsenal of information allowing to choose different casing mixes whenever you want, all while keeping far as moisture content goes

but untill then, just think about making mixes that are fluffy but moist --- not wet --- as they arent really proving too much water to the sub, but rather creating a microclimate that is preffered for inducing more efficient, and even pinning


#3 Lazlo


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Posted 30 August 2007 - 02:06 PM

Let me first say, the definition of field capacity ---- which is the amount of water a substance can hold against the force of gravity

Exactly. That's why some may here me say 2 drip capacity now.

#4 python


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Posted 30 August 2007 - 03:16 PM

moved to fungi.........

:thumbup: laz

#5 dial8


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Posted 30 August 2007 - 05:27 PM

But when I measure field capacity I do use the squeeze test. But, that water that drips falls back into the mixing bowl and what was in my hand gets mixed back in so no water is lost.

Squeeze test...take a handful of your mix squeeze lightly and you should see a tiny bit of water accumulate around the fingers. A hard squueze will produce a few drips.

#6 python


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Posted 30 August 2007 - 07:21 PM

an option to derive true field capacity would be a thin layer of "mix" put in a colander ---- wet it, and leave it till no water is dripping.........

even a thick amount... like a colander full of wet mix would essentially toss off the field a definative sense.......

thats why you have to find 'exact' amounts of water that are added to 'exact' amounts of material to get the 'exact' same result everytime.....

Like dial says, he uses the squeeze test, and thats what id say 80- 90% of people do..........and there is no need to change anything that works well........however, i should say that in the case of a casing mix (well a good deal of mixes)....true field capacity is probably a touch too moist.........

Also, please understand that I am just implying these methods as-to complete your interest in formulas/recipes ---- thus allowing you to form a portfolio of your favorite mixes

#7 {Mr}fLoYd



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Posted 30 August 2007 - 10:54 PM

Yeah Field capacity is a lot like everything else in this hobby. Failure. I dont mean that negatively but its true. If you look at a lot of posts the questions can usually only be solved by first hand eperience. how do i know if the popcorn is drained enough, is my casing too deep, ect ect. It took me years of casings and lots of substrates before i got the squeeze down. Its just trial and error. Taking a lot of notes is very very good but ultimatly if you just keep on squeezing substrate mixes and keep on writing things down you will get it. Not only that but a formula is only as good as the consistency of the product you put into it. If you change the brands of the components then your formula might not be right. So keep failing and keep learning. Thats what i try and do. persistancy is the only way to succeed in this game :) GL

#8 Guest_Mr. Natural #1_*

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Posted 31 August 2007 - 09:36 AM

Sorry about the improper formatting. When I cut/copy/pasted to the post pre-view page the text seemed to be 10 not 16. I thought the post pre-view page was wisiwig. Thanks for the edit python.
Thanks to everyone for all of the good advice. I have learned so much from all of you. I wish I had something to contribute around here besides questions. I wish I knew a small part of what y’all collectively know.
I may have understated my question. Which was about the last two mixtures.
At this point I am not really sure of which way to go.

By weight.

Is the 10%
coir / 80% Water / 10% vermiculite really to wet.
Is the 15%
coir / 70% Water / 15% vermiculite really to dry.
Another question about Coir/Vermiculite casing moisture content is this.
In The Mushroom Cultivator by Paul Stamets and J.S. Chilton on page 133 they describe an easy method to preparing proper moisture content for their peat casing mixtures. Saturate 80-90% of the material then add the dry 10-20% back.
Do you think that method is effective with a Coir/Vermiculite casing? If so what percentages would you first use?

#9 chimp


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Posted 31 August 2007 - 10:36 AM

I have never measured the amount of water in casing or sub mixture before. Except in pre-made mixtures like hippies BRF mix. I just put the water and mix until the moisture level is correct..If I put too little water I can always add more..If I put too much I can always add more material. Sounds like alot of mental work to
have everything precisely measured. Seems like it would take the fun out of it too.

#10 wayback



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Posted 01 September 2007 - 09:06 AM

Field capacity can bit a bit tricky at first, but the addition of those extensively extra recipies merely complicate an already delicate situation. Find a recipe that retains the moisute in your substrate for long enough for pins to form, and then hopefully fruit.

Me? I simply use 10 cups of peat moss, 10 cups of verm, and about a cup of hydrated lime. Oh yeah, I try to use distilled water if at all possible. I mix all those bad boys together and very well by mixing my dry ingrediants first. Afterwards I slowly pour just enough water to obtain that not so magical or mystical several drops of water when mix is squeezed fairly hard.

Naturally, too much water will result in increased contam growth, while too little will mean additional misting will be needed, and that can easily translate into less pins and fruits.

It's really not such a hard task, but yes, it often takes a number of attemps until one gets the hand of the end result. Also, one must take into account the amount of humidity where one lives when composing your casing materials. I've found that a little less water in the casings of high humidity areas works quite well.

Additionally, if you by chance think that your casing mix might still be a bit on the wet side, then distribute a half an inch or so in the bottom of your fruiting chamber tub. With the aid of gravity this should soak up the excess mosisture in a few days.

But don't worry bro, in this hobby there are many pitfalls that can either be viewed as complicated issues, or reduced to eaiser tasks through common sense. If more than a few drops can easily be squeezed out of your casing material, then compensate with the verm.

I hope you get the hang of creating good casings, because the yeild from a decent bulk can be a very rewarding experince. After all, for years I use to look at all those great pics that people send in and think, man if they can do it so can I. But keep in mind, these folks are sending in the best of their best photos, and they too have likely suffered a great many failures before comming up with a picture good enough for bragging rights.

Keep trying, patience is a virtue that pays of in this hobby. There's nothing like watching a great crop grow and produce another personel record.

Grow on bro, grown on and on. Peace.


#11 BuckarooBanzai


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Posted 02 September 2007 - 08:55 AM

I always test coir, verm or worm castings right before using them. Starting with 10 gm of the dry material, I add very hot water dropwise from a 60mL syringe and stir continuously with a fork.

When the material reaches the point where squeezing the 10 gm ball hard in my hand produces no more than two drops of water, I write down the ratio (weight of dry material to the volume of hot water) and test the other ingredients.

I then hydrate all materials seperately. I'll mix in slightly less water than I need and then stir, stir, stir until everything is uniformly hydrated. If the stuff is a tad dry (squeezing a fistful hard produces no water or only one drop) I'll add a small amount of water. If it is a tad moist (squeezing a fistful hard produces more than two drops) I'll stir back in some dry material.

I only mix materials, by total hydrated volume/weight, after I have the water level of each individual component exactly where I want it.

After mixing, a fistful of the substratre is squeezed hard. If more than two drops of water come out, verm is added to dry it out. I never add water after mixing up the substrate materials.

I always follow a rule that says "Too dry is WAY better than too moist."

#12 Mermaidia


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Posted 02 September 2007 - 03:27 PM

I always follow a rule that says "Too dry is WAY better than too moist."

Amen to that!

#13 Guest_Mr. Natural #1_*

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Posted 03 September 2007 - 05:31 AM

I will try that rule.
I really like the idea of squeezing an exact amount. Cause I have big clunky hands and always squeeze things too hard.
I am trying the dryer mixture 15% coir / 70% water / 15% vermiculite first.
I was using the 5-gram water per gram vermiculite Absorption Potential ratio I found in The Mushroom Cultivator, to try calculate the 90% moisture content that he recommends.
When I made the 75% water/vermiculite mix it was over saturated, the vermiculite could not soak up that much water.
So then I wondered what was the saturation ratio for my vermiculite.
I added 800 grams of water to 100 grams of vermiculite. After about 10 minuets I strained the mixture through a fine strainer for 10 minuets. Then weighed the water that came out of the strainer subtracted that weight form the 800 grams, to determine the saturation weight. I weighed all 4 mixtures to within a 10th of a gram.

Vermiculite saturation by weight.
1. 100 grams of vermiculite held 395 grams of water.
2. 100 grams of vermiculite held 383 grams of water.
3. 100 grams of vermiculite held 369 grams of water.
4. 100 grams of vermiculite held 389 grams of water.
100 grams of vermiculite held approximately 384 grams of water.
I weighed all 4 mixtures to within a 10th of a gram.
The first mixture was taken off the top of the bag. For the 2nd, 3rd and 4th samples I shook the bag up each time.
I did not think that there would be such variances between the samples.
So my vermiculite only holds approximately 3.84 grams of water per gram of vermiculite.
So maybe that when I used his calculations for my peat/vermiculite mixture the moisture content was too wet. They probably had better vermiculite.

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