saturated media extract

if you need to know whether or not you have over or under fertilized this is the correct method

Saturated Media Extract Method: This method is more accurate because it provides a more exact representation of field conditions but is more time consuming. Media samples are collected and put into a glass or plastic container. Slowly stir in distilled water until the media takes on a paste consistency with a little moisture glistening on the surface. Let stand for 60 minutes. Filter and then use your meter(s) to test the leachate for pH and EC

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Shoot for ~1.8-2 ec. The recommendation in the link is a bit high because its for greenhouse crops not cannabis. When I do it, I scrape away the top layer of "soil" and use a bread knife to cut a 2" x2" x2" cube of soil, roots and all, out of my container. Once the soil has soaked for 30-60min I use 6-7 coffee filters to act as a filter and squeeze the ball of soil in the filters to get all the water out I can for the test.

One thing to note, consistency of water additions is important for a reliable repeatable test.

IOW I like to pack the soil lightly before adding water and then I add water to the level of the soil. That doesn't mean I add the same amount of water every time, just that I bring the soil to the same level of saturation for each test.

http://www.greenhousegrower.com/production/crop-inputs/test-media-ph-and-ec-with-the-21-technique-pour-through-method-and-saturated-media-extract-methods/





As you can see I'm ~10 percent low, you can be sure that would translate to yield losses if not corrected before flower.





It'd be cool if we could get this stickied, I've never seen anyone post about this, and I honestly believe it will help a lot of fellow growers.

Sure did tbanks homie

Helpful tutorial. Not enough people are doing this. Runoff tells you something but this is much better.

Architect, do you ph adjust your media before transplant?

theother said:

Helpful tutorial. Not enough people are doing this. Runoff tells you something but this is much better.

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I think some people have read about it before but a pictorial always helps, I've always just seen it as a written guide. It's definitely the way to test if you want actionable/practical information

Architect, do you ph adjust your media before transplant?

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Nope, I use pro-mix hpcc. My tap is .2ec so it has a good carbonate level, which helps balance the pH naturally. If I were to guess at rootzone pH I'd say its about 6.2 or so give or take a few tenths.

Haven't really worried about pH for years, at least in medias other than water,

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bump