PPM and EC of runoff help

Good morning, all.

Obviously I’m new and have another question. Last week I watered my plants to runoff and measured the ppm and EC for the first time. (The meter is a cheap TDS/EC “blue” one). Water is filtered with a starting ppm of 79, ph 6.5 - no nutes.

4 plants, going on 8 wk old, transplanted to Happy Frog soil about 4 weeks ago.

The reading was high compared to what I see referenced here. At that time ppm was 1800 and the EC was 3360 (not sure how to read this, I commonly see like 1.2, 1.4)??

Today, 4 days later they were dry so I watered them again to runoff and measured. Nearly same results. (No nutes again)

Any idea what my step should be? Should it be a flush?

Plants look healthy and happy to me.


1.) How big are your pots?
2.) When watering how much water are you giving each plant?
3.) What’s your temperature in relative humidity
4.) Are you in a tent?

When you say you watered today and you got nearly the same runoff what was the exact runoff numbers including pH/ppm


This isn’t high for organic amended soils like the FF mediums. She looks healthy and I wouldn’t change a thing. Keep monitoring your run off PPMs and PH and start a nutrient regiment once that gets around 800 or below. Will this be an organic grow or will you be using synthetic fertilizer? If organic I would recommend scratching in the organic nutrients when the run off is around 1200, it’ll need a few weeks to start working. Synthetic fertilizer should be fead around 800-1000 PPMs to liberal run off and use a drench to drought routine unlike organic where you maintain a damp consistency :love_you_gesture:


5 gal pots, tent. 75 deg @ 58%RH.

Slowly watered to runoff, propped in bucket angled to allow to drain.

Plants were allowed to dry, then watered. I’m guessing 3/4 gal, maybe 1gal until runoff for each plant.

The numbers are nearly identical.


Using Happy frog soil in 5 gallon pots I always water with 2 gallons this gives me a four cup runoff. Like @OGIncognito said don’t change anything. You probably have two more runoff feeds of just H2O before your numbers come down to feeding numbers.


Excellent!! Thank you both!


This will be a synthetic nute process. FYI


Good deal, agree with @Lostgirl on monitoring the run off for feed time. I definitely recommend a drench to drought feeding or watering routine for soil and liberal run off with synthetic fertilizer. Without the ample run off the salts from the fertilizer can accumulate in the medium near the root zone, this will drive up your PPMs and tank your PH. Healthy root zone…healthy and happy plant :love_you_gesture:


@Highgrow we’re NC Grow Bros :love_you_gesture:


Thank you. I guess I was on the right path, just not watering enough (during watering) based on earlier reply’s. This forum (all of you) have been very helpful and I appreciate you all.


Nice! Havent seen but like 2 NC growers here so far. Small small word :metal:


Watered this morning and PPM & EC coming down. Watered 2 gal each plant no nutes.

PH 6.3
PPM 1363
EC 2820

Another 1-2 waterings without Nutes?


Those numbers look very good. One more watering of H2O only should put you in the 800 to 900 PPM range and after that dries you can start feeding again.


Fantastic! Thank you so much for your guidance.

Without this forum and without spending hours and hours of research, like many other novice growers I probably would have kept adding nutrients weekly based on a website I read when I started. You’ve prevented me from ultimate disaster.



When you start to feed after this next watering go small like 1/4 of what they tell you to feed on your directions/feeding chart.

When you get your runoff from that feed you want to see and maintain around 1,000 ppms every time you feed.

Adjust your feed up or down to achieve that 1000PPM

Keep that 6.5 pH when feeding as well. You ask all the right questions and your receptive to help. This means you’re going to do just fine


:blush: will do, thank you

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So my last watering runoff info is as follows.

Plant 1 - EC 3846 / PH 6.1 / ppm 2026
Plant 2 - EC 2108 / PH 6.5 / ppm 1052
plant 3 - EC 3012 / PH 6.4 / ppm 1503
Plant 4 - EC 3030 / PH 6.4 / ppm 1515

(Sorry, I didn’t break the details out in earlier post)

So, this being said seems like something is off on plant 1.

And, with the ppm levels where they’re at, I’m guess I should just water this time around and not feed?

The PH of 6.1 is out of range Growmie :love_you_gesture:


What PH water should I use to increase it?


Increase the input PH to 6.8 for a couple of rounds. Range of 6.3-6.8 for soil gives the best range for nutrient absorption Grow Bro :love_you_gesture: