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Hemp (Cannabis sativa L) tissue nutrient analysis data

spurr

Active member
Veteran
@ Tester:

By "negative health effects?" (of Si in plant tissue) did you mean on humans when we smoke/consume cannabis, or on the plants?
 

spurr

Active member
Veteran
Hello all,

Below are new tissue assay results of veg and flowering cannabis leafs, as well as a nutrient (fertigation) assay and tissue assay report (the lab knew it was cannabis).

Below are some quotes from the person who gave me these data. In the near future I will be posting new tissue assays on cannabis at various stages of growth and plant parts, ex., from veg leaf, petiole, floral bract and floral leaf, stem, etc. I will soon have access to a lab for many tests, working to design a cannabis specific fertilizer formulation based on larger tissue assay data sets.

Making a solution for cannabis, a' la Hoagland solution for tomatoes, is my ultimate goal. So that solution can be used in many studies, trials, etc., then data and results from one study to the next can have higher correlation. That and so cannabis growers can finally have a real fertilizer formulation based upon science, not pushed by those seeking to make lots of money.

(text below is from the person who had the tests conducted; the media type is SunShine mix #4)
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Plants from the tissue tests were of varying sizes and stages. I know it's not going to be helpful to you but I was trying to just get an overall assessment of plant health. CNS Grow & Bloom were being utilized w/ 1 tsp per 13 gal of epsom [at EC of ~2]. Samples were taken a few hours after lights on both veg and bloom. They were fertigated a couple hours prior. Leaves had no prep from me other than tossing into paper bags.

Solution test from the lab were as follows. Sample #6 was CNS Grow Hydro + 1 tsp espom per 13 gal at 2.2 EC and 6.1 PH. Sample #7 CNS Bloom Soil + 1 tsp espom per 13 gal at 2.2 EC 6.0 PH. Feel free to post all the lab data as if it were your own. In the future I'll be far more precise about what we need to measure and preparing accordingly.

Fertigation is run to waste. Mature plants are fed 3x a day via drip rings. Peak water/food consumption is about 3 gallons per 24 hr. period. Runoff quantity is about 15%. Plant are flushed with municipal water 2x per week. At beginning of flush EC of runoff is approx. EC 5.0. When flush is complete EC is about the same as municipal (0.4). Each container is flushed with approx. 15 gallons.

Water source is 100% municipal. Filtered on-site through sediment and carbon (for chloramines, etc). Annual water report shows Na range 15 - 70ppm w/ average 35. Ca 7 -65 w/ average 31. Mg average is 5.2. Total EC about 0.4 and PH 6.8.

Mature plants are fed with EC of about 2.2 and PH 6.0.


Leaf assay:
picture.php

CNS fertigation solution (with Epsom salt) of CNS Bloom Soil and CNS Grow Hydro:
picture.php


Lab recommendations from tests above:
picture.php
 

spurr

Active member
Veteran
I forgot to mention, the Ca and B could so high (re K:Ca ratio and Ca:Mg ratio; and K|Ca|Mg values) due to use of ideal Vapor Pressure Deficit (among other reasons). I calculated the VPD for that room where those plants were grown, and it was ~0.7-1.08 kPa, and thereabouts, maybe a bit higher into 1.15 to 1.20 kpa. With ideal VPD comes high uptake of Ca and B, due to consistently ideal rate of transpiration, considering the media was kept at a near ideal constant moisture status, which is better than very dry to very wet cycle.
 

spurr

Active member
Veteran
Below is a must read, IMO, for those interested in plant tissue assays (tests) for minerals (like N, P, K, etc.), and fertilizer formulation. The following presentation is not the end-all-be-all, but it offers insight I think worthwhile, at least it was for me. And besides, I am a fan of Bruce Bugbee, I like reading his presentations on nutrients and light.

This presentation is generally focused on recirculating systems (soilless media and water culture), but the info about plant tissue testing, etc., is applicable to many grow situations.
Nutrient Management in Recirculating Hydroponic Culture
by Bruce Bugbee
Presented at the South Pacific Soil-less Culture Conference Feb 11, 2003 in Palmerston North, New Zealand
http://www.usu.edu/cpl/research_hydroponics3.htm
 
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