Low EC in soil after ferts... are soil tests accurate

father nature

Well-Known Member
I have 2 outdoor plants. They are about 5 feet tall in 27 gallon containers. 2 1/2 months old. I've only fed them once a month ago. They seem to be doing ok but they seem a little lime green so I thought I would give them a good watering with ferts

I mixed up some all purpose fertilizer 18 18 10 in a watering can. I tested it with a Bluelab EC meter.
THe solution came up as 1.9 EC which I thought was good for a full size plant.
I watered the plant with 4 gallons of solution until water came out the weep holes. I haven't watered in awhile and it was ready.

15 minutes after watering I tested the soil. I dug a couple inches down to the roots and mixed up a half cup dirt with a half cup water for a 1 to 1 ratio.
The soil test came back at .3 EC and that was using tap water with an EC of .2. I know I should use distilled water but I didnt have any.
So I only gained .1 EC after fertilizing. I wasnt expecting the soil to be the same as the solution but I thought I would gain a hell of a lot more than .1. I tested this on 2 plants and they both came back with the same low reading. One plant I watered 3 days ago and is showing no signs of nute burn

So Everything I'm reading says plants should be around 1.8 during veg and I'm barely showing a reading directly after fertilizing. I would have to add a boatload of ferts to get that high according to my test

I'm completely confused.
How are people getting such high readings?
Should I add more ferts in a week?

Any input welcome

Will be calibrating EC meter tomorrow when the hydro store opens and I can get test kit. But I thinks its accurate
Soil is around a 50/50 mix of FF and MJ performance organics mixed with perlite. Soil drains well and is well rooted
Please dont make it an MJ bashing thing. First soil grow and what's done is done.
 
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