Plant sap testing

[MountZionCollec]

this is basically the modern classroom and it's people like you who have the knowledge, tools and plants to keep this experiment moving forward. Please do continue to post your results as small ganja farmers around the world are learning from Northern California farmers like you, not only that but other small farmers in California are improving their techniques to a point where they'll survive and thrive during legalization.

Do I share? I am only NOW coming to the point where I feel I have something to offer to my fellow growers and I will continue to try to do just that and plan to continue contributing for years to come. I will reveal my entire process from seed to sale to anyone who contacts me. I'm not sure I would be good managing a thread.

I am very good with post harvest handling and storage techniques so if anyone who is reading this is having trouble in that department send me a message either private or on my profile page.

I used to hold the idea about not releasing certain advantages I discovered but realized I would only be helping big business and i don't fear my fellow small farmer. If small farmers don't drastically improve their post harvest handling it won't matter how well they can grow it. The money is always made in processing (dry-trim-cure-store-wholesale). Farming it is quite cheap if you look at cost per acre.

 

[Humphry Davy]

Thanks MJ.
Thats what I needed to know. If you need any help collecting data, please dont hesitate to ask. Ill contribute what ever I can to help get a protocol established and get some solid numbers. My first Ca test I did at a friends house on new growth shoots... Tested at 30ppm. So I assume 4000ppm is super high for new shoots since that is where Ca def will show first .. should new leaves be that high 3-4000ppm?

For the record: Personally when I ask a question online, and anyone answers. If I chose to use that info in my garden, I dont hold anyone responsible for what happens in my garden except me. If I was too lazy to double check to confirm if your answer was right and then something goes awry, thats what I deserve. Being unable is one thing. Being lazy and expecting to use another growers research and hard work to get instant results is deserving of failure. Thanks for the disclaimer though. Ive been searching for the answers and havent found anything definitive not even loosely. That helps me get at least a ballpark est..

I guess once your soil hits Albrecht numbers then you test sap levels that should be the baseline. Your thoughts on that?

Just because the soil test is good doesn't necessarily mean the nutrients are as available as the test might indicate. It's a good start, but I wouldn't base sap guidelines from soil test data.

Right now my indoor plants are at 83% Ca and 1.7% K. No sign of K def and Ca/Mg uptake is not hindered. I don't know how it will end but the plants look good now. Albion K on hand for foliar if I see any sign of K def...24% K vs 7 for phtk

Have you confirmed no K def with sap testing the new and mature leaves? I ran similar Ca:K ratios and got healthy plants but lower yeild. I believe AEA stated Ca:K ratio is a big determinant on fruit size, one for building the volume the other for increasing the density.

 

[Humphry Davy]

Another note on basing the sap guidelines on soil tests, if you got a total test, paste extract, and the standard test and everything checked out ideal, then yes I would base guidelines on those or at least that would give you a good idea.

As for data, I'll be doing tissue analysis my next entire grow. 19x 100 gal geos start to finish. Going to try to get the soil balanced before the plant ever hits it. I'm hoping to have the extra cash to get the plant sap press and some laquatwin sap meters.

 

[milkyjoe]

I would base nothing about sap on soil tests til you have a clear understanding of a particular cultivar. My theory is because of lack of knowledge in breeding some strains cannot take up nutes through the roots efficiently through the roots. Same soil...side by side...sap pH in one is 6.4 and the other is 5.something.

Test it with anything with that durban f1 in it. See if it vegs faster under t5s or 1000s...it can't take enough minerals in to convert the energy to growth...I think.

Then foliar the fuck out of base cations...bypass the root system. No more red petioles, no more low sap pH, fatter stacked colas.

Just a theory really. Someone else test it...perhaps I have gone insane.

Anyways...no k sap meter for me yet...so that was simply observation of older leaves

 

[milkyjoe]

Labs get a little conservative beyond a certain terpene level on tissue testing. Do they know what you are up to?

 

[Avinash.miles]

Whoa- plant sap analysis and testing for brix are two entirely differing things. A simple set of vice grips or a garlic press are good for brix testing, but plant sap analysis requires something completely different, no?

i'm wondering this as well, do u use the same masticated plant juice as for brix testing to test plant sap pH and ca / k levels as well?

 

[Humphry Davy]

Labs get a little conservative beyond a certain terpene level on tissue testing. Do they know what you are up to?

Yes they do. Lab isn't too far from me, they're picking the samples up in person. I'm hoping soil test data and tissue data will tell us quite a bit.

As for the K, considering the plant demands a little more toward flower, I'm going back to slowly irrigating K throughout the grow, most likely K sulfate. Rather than front loading the K and it anagonizing other cations during veg. Start light and end light on K, try to slowly feed the K and maintain low K levels in the soil.

 

[milkyjoe]

So here is a cherry pie. Literally inches away from a hanging vert 1000. I foliar sprayed the fuck out of it to keep sap pH up to 6.4.

It is a sample size of one so it don't mean anything. But barely a few red petioles, no colored leaf (daytime temp 10 degrees F over nighttime, 82/72), and light green bud.

Ima find out more this summer with some gsc...but you can bet I will foliar it to maintain sap pH.

 

[Humphry Davy]

I wish I had access to a cherry pie clone, I've heard Ann Arbor has clones but when I looked online at the dispensaries most of me just had strains from breeders on attitude.

What is your foliar program btw?

 

[FatherEarth]

K trumped by high Ca uptake stimulated by Si

K trumped by high Ca uptake stimulated by Si

So I was looking at some sap analysis papers and came across something that may answer the question about the potassium silicate and K uptake.. Not sure if there is an order to the application or what. Notice what the chart says about applying Si to tomatoes..

Si:Stimulates Ca uptake, firm leaves. Decreases PM, Botrytis,Yellow calyxes and calyx fungi

:up to now no disadvantges in tomato, in soft fruits
K uptake will be lower caused by high Ca uptake

 

[FatherEarth]

Another note on basing the sap guidelines on soil tests, if you got a total test, paste extract, and the standard test and everything checked out ideal, then yes I would base guidelines on those or at least that would give you a good idea.

As for data, I'll be doing tissue analysis my next entire grow. 19x 100 gal geos start to finish. Going to try to get the soil balanced before the plant ever hits it. I'm hoping to have the extra cash to get the plant sap press and some laquatwin sap meters.

Right, thats what I was thinking...

about to run 45 100 gallons outdoors in a light dep. Ill know if my soil is worthy sometime this week. Im waiting on test results now. I may have too many cultivars for solid baseline data though...

 

[Humphry Davy]

Couldn't you use the same method as for K but in reverse? If old growth has higher levels of Ca than less mature growth than bump up Ca?

 

[leadsled]

Couldn't you use the same method as for K but in reverse? If old growth has higher levels of Ca than less mature growth than bump up Ca?

That methods applies to N,P,K,Mg since they are mobile.
Ca is not mobile.

 

[milkyjoe]

Ca depends on capillary action highly influenced by the amounts and ratio of B and Si. Without those it will not move to growth tips no matter how much you have. That means you can't reliably count on old v new leaf differences

 

[Humphry Davy]

That methods applies to N,P,K,Mg since they are mobile.
Ca is not mobile.

Which is why I stated to test in the reverse order, if lower leaves test higher than newly mature growth it could signify a deficiency or lack of a synergist.

Ca depends on capillary action highly influenced by the amounts and ratio of B and Si. Without those it will not move to growth tips no matter how much you have. That means you can't reliably count on old v new leaf differences

Agree, but it could be a another parameter, which could indicate Ca shortage or a lack of one of its synergists you stated or an antagonism occurring.

I think that goes for any element showing low on sap or tissue, have to consider all factors that could be limiting.

On another note, reading how many state that sap pH relating to anion/cation imbalance. With high pH meaning an anion shortage/imbalance and low pH meaning a cation shortage/imbalance, I understand the balance of charge....however say you have copper (II) ion, this is positive, yet it's acidic in solution, so I think it's more involved then simply saying a cation will raise the pH. Now for major cations I could see this as they're stable ions which readily dissociate, and even with a foliar, as they're accompaning anion, generally sulfate, is basic in aqueous solution.

 

[milkyjoe]

That is an amazing observation on Cu. It is the one micro cation that does not get tied up with P. I definitely don't understand fully

 

[BobbyIronsights]

Great thread people.