Salicylic Acid: where did I go wrong?

[Triffid]

Fairly new to growing and trying to reduce costs, I had read lots of good things about salicylic acid, so thought I would give it a go.

Purchased some powder, did some more research and calculations and decided on a method and amount.

DWC with 35 litre reservoir, gorilla glue auto entering it's first week of flower, running AN.

I used 0.143g of salicylic acid per 1litre of water, so 5g.
Dissolved the powder in 20ml isopropyl alcohol, then added it to the reservoir after a water change.
Checked at 1, 2 and 4 hours, everything looked good, EC around 1.1, PH stable around 6.2.
Checked again after the plants sleep cycle, about 12 hours after adding, and the plant was just looking the slightest bit droopy.
Off to work and check in when I get home (around 20 hours now) and everything has wilted, stalks and all laying flat on the reservoir lid!

Flushed the solution, washed everything as well as I could, reduced light, reduced EC levels, and it took about a week to recover and lift it's leaves back up.
Half the leaves had crisped (were still green but snapped and crumbled when touched), and the other half showing what looked like severe nute burn, brown tips with yellows and oranges down the leaf.

Anyone with experience using Salicylic Acid, what did I do wrong?

 

[Captain goodvibes]

Not sure about the salicylic acid but if I wanted to kill a plant I would give it isopropyl alcohol .

 

[Triffid]

I thought 20ml of alcohol in 38litre would evaporate off?

Would I need to let it sit so the alcohol evaporates, or need to heat it to burn off alcohol?

Any other ideas of how to get salicylic acid powder into solution without alcohol?

 

[Captain goodvibes]

Im no expert on DWC, just know alcohol is a good plant killer. Just wondering why you feel the need to add salicylic acid to your mix. Sounds like your plant was doing ok before you added the mix, why complicate things? Ive seen some literature which states that salicylic acid is beneficial to plant growth, but so are a lot of things. As you are a newish grower my advice to you would be to get the basics right first before adding advanced growing techniques. Ive grown thousands of plants and the one thing I have learnt, much easier to kill a plant with kindness than it is to kill it with neglect. Ive lost a lot of plants BTW mainly outdoors but also indoors and learnt this rule at my cost more than once. Good luck with your growing.

 

[Triffid]

I have done 4 complete grows, and this current one. 2nd and 3rd grow I used Bud Factor X, 1st and 4th I did not. All the same strain, from seed, so not completely reliable data, but thats my experience =). The grows I have done with BFX have been significantly heavier in final weight and stronger in effect. (Of course there are other factors as well, but enough evidence to go with)

Bud Factor X is prohibitively expensive, so I was trying to replicate the effects of BFX without the humongous cost.

Idle google research indicates that the effective ingredients in BFX are Harpin Protein, Salicylic Acid, and Chitosan.
More serious research in scientific journals etc indicate the effectiveness in all three of these in getting a bigger harvest, and having a more disease resistant plant.

Having had a few issues with bud rot when not using BFX, and to keep my plants healthy, (high ambient temp and humidity) cheaply, raw ingredients seem the way to go.

Harpin Protein - Super easy to find, water soluble (Instructions insist foliar, very easy to follow)
Chitosan Oligosaccharide - Super easy to find, water soluble, in reservoir, .124g/litre (.5g/gallon)
Salicylic Acid - Easy to find, not water soluble, in reservoir,


Anyone have suggestions on how to get the Salicylic Acid into solution, and what dosage?
.124g/litre (5gm for 38litre res) dissolved in isopropyl, absoutely fried my plant

 

[Triffid]

So, I did some quick experimentation, tried putting some isopropyl straight in the reservoir, not even the slightest twitch from the plant. So I don't think the small volume of alcohol/reservoir caused a problem.

Looking around online, (Research Papers), there are wildly varying doses of Salicylic Acid (SA), for various crops and circumstances, ranging from 1mM to .03mM (Molarity Calculator), but not much about Plant Specific research that I could find with relevance.

Finding labels, or lab analysis, revealing the % of SA in a number of popular nutrients for hydroponic reservoirs, a little challenging, but achievable! Having found 6 different products with reliable data, (another 4 with unverified data that would fit within the parameters), breaking down the instructions to a %/litre, I got from 0.010gm to 0.013gm/litre, a surprisingly small variance for 6+ products.

Correct dose for my reservoir, 0.455gm Salicylic Acid (35l@0.013gm SA/litre), awaiting new data for update.
My error, 5gm SA for 35litre, I multiplied the wrong fields, ended with a solution ~10x as strong as it should have been....

TLDR
Massively overdosed plant on Salicylic Acid, 5gm SA in 35litre reservoir.
New calculations 0.013gm SA/litre * 35litre = 0.455gm SA

 

[Nunyabiz]

I use Aloe Vera flakes for my Salicylic Acid in soil, not sure how that would work in DWC though.

 

[Triffid]

Got it sorted now, and the results have been pretty spectacular.

I put the 0.455gm of Salicylic Acid ( 0.013gm SA/litre ) into a tube with a small amount of Isopropyl and shake till the powder is in solution.
Add the solution into the reservoir.
Done.

Some experimentation shows that if you add water to the SA solution, it goes back out of solution, no good, have to add the solution to a much larger volume of water.