CalMag Adjustmet w/ Compost Tea Watering?

@Bulldognuts @Myfriendis410 @merlin44 morning/afternoon gang. Hope you’re staying warm depending on where you are.

After reading some posts and sites I’m thinking maybe a good ole flush is in order tonight. They are due for nutes but given these conversations and reading some of @Covertgrower old grows, it seems like this should be done when switching to flower.

So my plan is to haul them to the shower later on, get lukewarm tap water and ph it to 6-6.5, and just water them till I hit a tds that is desireable. Is that right? And is that tds 50 or whatever my tap water tests at right out of tap?

Being that I am almost one week into flower, this is still an ok time right?

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Yes this is okay, but the last picture I saw it looked good. I don’t practice flushing unless I’ve been over feeding, or I have a PH issue. @stltimmy1979


Thanks @Covertgrower! I think I’ll just roll with the recommended nutes for feeding tonight but will only do 50percent of what they recommend. I’ll try to get the runoff going but haven’t had any deliveries yet today so no meter yet. I’ll also grab some pics tonight.

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This is where your TDS meter come in: mix to a specific TDS, water to runoff and capture the last 1/4 cup of that and measure as well. This gives you data on what is happening in the root zone and can tell you when or if either water-only or a flush is necessary.

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OK this is starting to make sense. Given I don’t have my meter it seems like it’s recommended that I just do a water only tonight. Is that fair? Another dumb question, how do you capture 1/4 cup accurately, or do you mean whatever amount is in my plastic tray that is sufficient to cover the sensor? Thank you @Myfriendis410 et al

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Well water was not needed so hopefully the meter arrives tomorrow. I did snap a couple more pics.

I still only have these hlg at half power. Every time I turn up a bit I think that could be causing some burn but it’s cool on the canopy and the light is the recommended 30” away.

The Gorilla Glue is pictured below. It is the worst looking of the bunch with slightly curled down leaves. It tends to always look like this not when she starts to get thirsty. The second pic is of a fan leaf in that same plant. Notice the color. No signs of any pests.

Then this is a GSC that looks pretty darn good. The lime green new growth but there is a very slight yellow on some tips of other GSCs

Anyway the beat goes on!

@fano_man @Covertgrower @Myfriendis410 @Bulldognuts
Morning gang. See above pics from last night. And here is the one gsc that I thought I might have messed the top up (or fimmed) that was really thick during veg at the top. Now almost one week into flower check out the top, I had to pull away leaves to see the load of small flower sites. But are they too small? Will they take away from other bud formations? It’s odd looking imo but what do I know :rofl:


I’ve got a Bubblegum photo that is exactly the same.

Just the last bit of runoff: don’t mix with the rest and yes, just enough to get a reading. If you are using FF trio, mix to around 1,100 ppm and PH to whatever your medium recommends. Water enough to get 10 to 20% runoff, capture the last bit of it and measure. Again, depending on medium, you will have a value that you can reference for the next either feeding or watering.

For example: I’m in soilless. I feed in veg at 900 ppm. When TDS gets up 50% or so above that number in runoff, I either do water-only or run enough excess water through to ‘reset’ to a value below 900 then resume feeding. Doing this will ensure you do not over feed.


This is great. Of course more questions lol

What did your bubblegum end up looking like? What caused this?

When using the trio I believe there is an order? And when you say mix to 1100 ppm does that mean just stick the meter in my water and add what amount of each I need until it hits that number?

On your example of 900, let’s say your water is lower I don’t know 100. You’ll add each of the three and monitor as you mix each? And you say 50 percent over does that mean your reading out of the soil is 1350 when you water at 900? Pardon my ignorance how does it increase is that due to nutrients left from previous watering as well as what is in the soil that hasn’t been depleted?

Thank you @Myfriendis410


Sorry I mentioned soil and you said specifically you don’t use it. Lol. Just roll with my example🤣

That’s it about 4 weeks ago: it’s a chunk.

Probably; a published grow schedule should tell you which first. Silica (if used) then Cal mag, then whatever else.

There is a little trial and error to get right but here’s what I do: mix per package instruction. Measure TDS: say it’s 1,100 and I want 900. Add water until TDS drops to 900 then PH. Next time, mix a smaller amount, dilute down to target TDS and you’ll have your correct volume. PH as normal.

In soil this number will be much higher, like 3,500 ppm or so. Soil buffers salts differently so can sit at a higher number during veg but by the time you are deep in flower the soil is mostly depleted and behaves more like coco. I don’t bother with runoff in veg unless there’s a problem. Only in flower do I perform this. Essentially you feed until soil contains a higher salt concentration (buildup) than you are putting in. Fresh water for a few feedings will dilute those salts suspended in the medium and the plant can access/use which of course brings it down.


@Myfriendis410 i truly appreciate you taking the time to write this out. It’s a lesson for me and this is great!
Ff has a published schedule I guess I’ll go in that order but I may email their support to see what they recommend. I’ll add that to the thread later for others info.

So in the salt buildup is that why ff recommends their flush before flowering? Is it a best practices to just flush things when switching over?

I can’t wait to get my meter and see what’s going on!


I’ve emailed their support. Here is the schedule online. Notice the ppm says like 2000 ppm. What is that relative to the 1000 number I’m shooting for. Is that the number I’m shooting for?

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Yes; FF tends to aggregate salts in the medium and needs flushing.

Be aware that FF is in Canada and as such uses a different PPM scale: ours is 500 or salt scale and Canada is 700 or Potassium Chloride scale. Numbers on their schedule will be higher than you want to run.


@Myfriendis410 you beat me to it. See the image above. Darn Canadians lol.

Based on an article I remember seeing the target for flowering in soil I believe was 1000-1050


Yeah; depending on strain you can push a little higher. If you have gucci lights you can push em higher too as there is going to be more vigorous activity with more photons. Don’t get too set on an exact number as reading salt content is more “around” your number than exactly.


Thanks @Myfriendis410 I think that’s it for now. Just waiting on the meter to arrive and then go from there. My option would be to just water and then check the PPM, or Fert at 50% and see. Not sure if you saw the pictures of the GG I posted above, specifically the slight curl of the leaf then the discoloration on one of the older fans (that might be Fert water splash). The others look pretty good minus a very slight yellow at the end of a couple tips. I dont want to skimp on prime time for nutrient intake nor do I want to burn. So that’s today’s dilemma I can wrap my brain around till lights coming on.

oh, re lights, these are under HLG 650s.

Have yourself a great safe day :slight_smile:

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Yeah; plants look fine. I think you are being a good weed-daddy. (or mommy haha)

You aren’t a bother; tag me anytime you have questions. That’s what they pay me the big bucks for haha.

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Thank you, I prefer not to gender identify. LOL. Actually I’m a middle-aged white dude who happens to live in the middle of the states and is celebrating my 42nd birthday today. As plain as they come LOL OL


@dbrn32 is in your neck of the woods.