Plz help me understand PPM!

[ross]

Ive never really bothered with PPM and always thought it was kind of a hydro thing (i do soil) but might be purchasing a bluelab combo meter that has PPM so figured if I could use it to my benefit somehow I might as well. I know there are scales with ranges to use for different stages. I use tap water so I will already have dissolved solids in my water and Im not really sure if the scales are for RO water or what. Do I read the water plain then read it nuted and subtract the difference to apply to the scale if Im not using RO water? Any and all info regarding PPM would be greatly appreciated. I found it fairly hard to research cause no one says parts per million and PPM is often too vague lol. Thanks guys!

 

[Growdude]

PPM is a conversion from EC, its a measurement of conductivity.

There are 3 different conversion rates, hence the confusion with PPM.
Here is a link to a chart, US is normally the HANNA .5 conversion rate.
http://www.manicbotanix.com/hydroponic-grow-guide/ec-to-ppm-conversion-chart.html.

I don't deduct the PPM of the water when looking at the final strength.
It shouldn't be high enough to matter either way.

 

[zem]

ppm parts per million. it is the measure of total dissolved solids in a liquid. you dont subtract the ppm of tap water from it. the concentration if too high or too low, the plants will suffer. you can use it to you benefit in many cases like if you add a certain additive, you measure before and after you add to know how much you really added in ppm of that additive. in soil, you can only measure dissolved fertilizers and runoff water, it does not measure the compounds, but just the dissolved solutions

 

[ross]

ok cool I think I'll start PPMing my nutrient solution before I water. I found a PPM chart I think was from canna or somebody where it starts at 100-200 for seedlings and goes to 1000-1600 for full flower.

 

[Hushpuppy]

Its good to check the water initially so that you know where your water is. The meter will tell you how much dissolved mineral is in any water. If you stick it in RO water it should read 0, or if it is a very sensitive meter, it might read up to 5-10 depending on the quality and age of the RO system. But for you running tap water, it is good to see if there is a lot of something in the water like salt or calcium, or other heavy elements that could hurt the plants.

If you water reads under 100ppm then it is ok and you don't have to worry about it. If it is over 100ppm then you should have it analyzed to see if there is excessive salt, calcium, or chloramine/chlorine as these can cause issues if they are present in high amounts.

Using the ppm meter for following a feeding regimen is good to see where your plants feed best for the existing conditions, and to prevent over feeding. With seedlings, you start low and quickly ramp up the ppm each week as the plants respond, until you reach a max for that plant. In veg I don't push my plants hard since being inside grows, they don't need as vigorous growth. I usually run my max around 600-900ppm depending on the plant strain.

Then it is really helpful when transitioning from veg to flower as you want to ramp up the bloom nutes while backing off the grow nutes, but maintaining the total ppm level and continuing to ramp it up to a max of 1300-1600ppm.

 

[7thG]

Is it really worth the effort to worry about PPM if your in soil though?
Just wondering?

 

[Hushpuppy]

That depends on the soil method you are using. If you are using soil only for a root support medium and you are feeding wholly in a synthetic setup, then yes it is necessary to check the ppm until you get the levels down for that plant. I have had plants and nutrients that I ran for several cycles and didn't ever bother with checking ppm and that is in hydro. But that is because I had already learned both the plants and the nutes by heart. But for new strains or new nutes, I would go by the numbers all the way for a couple cycles.

For soil in synthetic nutes, I would do it the same way. Now if you want to do organic, you can put the ppm pen away as you don't need it, and it wouldn't be accurate if you did use it.

 

[WeedHopper]

I always feed till I get a little Turn and Burn and back off. Have never had a PPM meter. I gotta TDS meter with my Zero water picture,,never used it eather.LOL

 

[trillions of atoms]

Usually 200-250 is high ppm for city water. Usually it's bicarbonates that are hard to buffer.

If it's over 200 and hard water they make a GH solution called hardwater micro. This works well for starting solutions at around 280 ppm. More than that the buffers can't handle it and will need to be filtered

If your curious what's in your water take your sample to your local water authority.

If your solution is hard to keep buffered you probably need to run RO.

Lot of good points here but your meters will tell you everything that matters.

If ph stays outta wack you need to filter hands down.

 

[WeedHopper]

So will the TDS meter work? Never used them before for growing. Just a PH/Temp Meter(Pen).

 

[WAGMAN007]

Try this thread on another forum it was helpful to me.

http://forum.growkind.com/showthread.php?t=32657

:holysheep: **** to the people

Wagman