Tds; what's up/ understanding

Looking for imfo about tds. What do most growers use as a guideline for your plants best usage? I understand what goes in when you water, but what are acceptable numbers for the best growth of your plant? thanks to all

It would be helpful to know the context of your situation. What medium are you growing in?

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fox farm

Gotcha. Do you already own a TDS meter?

Yes, I have one Health Metric.

EC/TDS/PPM are important to know in hydroponic mediums. Personally, I’m not certain there’s much value in measurement in soil, provided you are following a bottle formula. I might check the PPM just to confirm my mixture matches the manufacturer’s, but it’s not really going to tell you much. I would not run at full manufacturer’s strength. Instead I’d go 1/4-1/2.


@KeystoneCops Has you covered. He knows his stuff for sure.:+1::metal:

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Thank you for your wealth of knowledge. That is why I like to use this forum. thanks again this hit is for you


If you want a more detailed explanation of TDS as it relates to soil or hydro, I can elaborate, but IMO it isn’t that interesting or relevant to soil.


No by all means. I think that there maybe something I may need to know or aware of.

In hydroponics, a higher EC makes it more difficult for the plants to pull the water in, which slows transpiration, possibly slowing photosynthesis. You end up dialing in EC/PPM through trial, error, and data collection strain to strain. At least, that’s my opinion on how you should do it.

Total Dissolved Solids isn’t the same as nutrient levels. When we add nutrients, we raise EC/TDS/PPM, but in order to measure the NPK (etc) you’d need an instrument like a colorimeter or more sensitive mass spectrometer. Those devices are impractical for home growers.

The more I dig into soil practices, the more I’m convinced we shouldn’t be adding synthetic nutrients. Instead we should be developing a healthy rhizosphere and adding organic matter via companion planting and top-dressing.


So you can use manure tea to water your plants?

Keep in mind these are only general guidelines. Not something you have to stick to. Values are in PPM (parts per million)

Seedlings: 100-250 (nutrients aren’t really needed here, hence there’s not a lot of particles needed)
First Half of Vegging Cycle: 300-400 (this is usually after you transplant, which still doesn’t require many nutrients)
Second Half of Vegging: 450-700 (you’ll start giving your plants more nutrients at this stage)
First Half of Flowering: 750-950 (your plants will be eating more as they grow, so they’ll be taking in more nutrients)
Second Half of Flowering: 1000-1600 (this is when your plant’s eating the most, especially if you give it additives)
End of Flower, Entering Harvest: As close to 0 as possible (this is when you’ll be cleansing your plants with plain water, so you don’t want there to be a lot of particles left over)


Thanks, that was what I was looking for, some guidelines. thanks again this hit is for you!!!

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That’s specific to a particular brand, correct?

Nope, just a general guideline for soil growing.

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Sprouted Seed Tea to give enzymes, and compost (top dressed, not tea).

If you’ve used this, what soil and what nutrient line?

@thecount13 here’s a couple more tidbits for you…

People always make things more complicated than they need to be when it comes to growing. Don’t put too much weight on the whole PPM thing. That’s why I stated they are just general guidelines. The most important thing is to pay attention to your leaves. They will tell you the most about how happy your plant is.

The other thing is - I just noticed at the top you mentioned you are using Fox Farms soil. I didn’t see where you mentioned which one, but I’m going to assume Happy Frog or Ocean Forest, since they are the two most common. You can follow the PPM guidelines I gave you when using those soils and your plants should be happy, but - you really don’t need to give them any nutrients at all for a while with those soils. If you want, you can just give them plain water with the pH adjusted somewhere between 6.2-6.8 and let the built-in nutrients take care of the plant. With Ocean Forest it will typically provide enough until 2-4 weeks into the flowering stage and with Happy Frog a couple of weeks less. If you go that route, just check your runoff PPM once a week and start giving the plant nutrients when it drops to 1000-1200 PPM, using your visual judgement of the leaves at the same time, of course.

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Thanks this was a wealth of valuable info. thanks double hit for you

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