How do i use my tds meter

Can any one help me or teach me how to use a tds meter. I was advised to get one am in week 5 of my very first grow of autoflower and first ever grow of any kind of plants. Started this with the thought of doing good but now am having second thoughts i have 2 at 5wks and one at 3wks. Choose to do a gap of 2wks so that if i do mess up al atleast have one turn out decent but now am sceptical. Am doing it on a tight budget and not good equipment.

We will need to know what grow medium you’re using and the nutrient line.

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Bio bizz nute line Bio Nova soil mixed with perlite and vermiculite. In a mix of 10L of soil 2L perlite and 2L vermiculite. And in my room i also have superthrive the original vitamin solution. Plant magic plus magne-cal + bio bizz alg.a.mic, fish mix , bio grow ,bio grow , topmax and 50ml bottle of plagron green sensation. Av only used bio bizz stuff i have there chart but was putting more water in than the 1l i was doing 1.5l to 1ml of what i was adding or telling me to add on there chart and i was ph my water but not the feed until a couple weeks ago or a bit less. If that help. I am not a green finger person until now. I really enjoy it but i want it to be worth it or it might cause a divorce lol.

I did a search and could not find a ppm or ec reference for that line of nutes. It’s hard to say where your runoff should be with that particular line, but if you measure your tap water and runoff and let us know how old the plants are, we should be able to help you fight it out.

Thanks i will let you know when i next water them and will let you know. Can you give me a step by step guide in what to do. That way i can see if am doing things wrong when testing and watering the girls. Do i do them all separate two are in the same mix and the other is in a different one as i was giving some advice about soil brand and well budget aswell. And i named them so its easier for me. I have 3 two that are 5wks and one is in bio nova soil mixed with perlite and vermiculite. And my other 5wk one is in soil mix with coco coir perlite and vermiculite. The soil in that one is a cheap mix of 3 types i was given from someone who grows different plants. Anyway i did start them all the same way it only changed when they were transplanted the first time and mistakes i made in pot sizes caused me to have to transplant them 3 times. And i have a 3rd plant that is about 3wks now one that i am doing without mistakes i hope.

You’ll want to start by measuring the ec and ppm of your tap water. Add full strength nutes according to the chart for your line. Measure the ec and ppm of the solution before watering. Water your plants as per usual and correct runoff from each plant individually, then measure the ec and ppm of each plant’s runoff.

This should give us a pretty good idea of where you’re at. Are you having problems or seeing signs of over/under feeding?

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Nope no under or over watering. Apart from when they are finished. Thanks…

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@3high5you if you need help, let me know!


Thanks @3 i will need every bit help i can get. Al take new pics of the girls today and post them so you can have a look you will see i have and might still have issues with one however am worried i might have ossues with both my older girls. And ive got a 3rd at 3wks doing good. So i dont want to make mistakes with her so that i can have 1 good plant or decent plant out of 3 unless i can get it all turned round and i should still have 4 to 6wks on 2 of the girls and and 6 to 8wks or so to harvest time. And am probably on a different time difference in my country.

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@bob31 @Mikos
I’m also here to assist if needed
As far as the tds meter
You should calibrate it when you fir get it and check it once a week to once a month depending on quality and storage habits
With that said
You’ll put water in container bucket whatever
Place meter in to water and swirl it around for 30 seconds Or so let Meter stabilize and read numbers that the ppm of you water
When mixing nutes you do the same after mixing well
And that’s the stresght of your nutrients mix
You should obtain a feeding schedule from the mfg of your nutrients and use that as a base line adjust feeding toplanys reaction
Some plants love to be feed and some just like kids are fussy
Happy growing :v:️CB :cowboy_hat_face:
Ps are you flowering yet ?
To determine ppm of soil you’ll need run off from pots


My tap water is reading 43ppm is tht right. Seems low. But then i dont know wat is low or high for a plant or human for tht matter. Hopefully i can feed them soon but am not sure if i want to give them feed or what to give them av got different nutes i was even given a sample bottle of stuff and i just dont know what to do. @Countryboyjvd1971 am getting lots of help and advice so i hope i can rescue this grow.

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do you have calibration solution @Mikos

Yeah its calibrated already it was a gift from another grower. And am waiting on my soloution arriving but its supposedly calibrated

I got run off of my 3 plants and they are all different one read 1311 one read 671 one read 532 av not phd thm yet but will do as soon as i get a sec. On dinner duty lol

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Ok sounds good @Mikos I’d recommend you pH the water Everytime before giving it to the plants. They don’t tolerate pH swings well.

It’s normal for them to have different runoff TDS. Are they all the same strain, size pots and soil? What was the TDS going in?

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Just plain phd water for them soil got different from my soiless one am just about to feed them there first feed since i flushed them all and this will be the first time i will have used my tds on thm with everything tht ive been advised down to phing my water and tds it before it is given to them with both ph and tds meters working and calibrated propely.

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My tds is reading 797 and ec is 1695 @bob31
And ph is 6.84 is this anygood

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Yes but for TDS you you need to check the same as pH. From the tap, after you add nutes and again the runoff. Otherwise you don’t know what is going in so don’t know if runoff TDS is good or bad.

Also mix nutes and then adjust the pH.

Yep those are good. So add your nutes to the water then give them a good stir of shake and then check the pH and TDS again

Thts wat i did my reading from it will i just feed my girls on tht @bob31