CalMag Adjustmet w/ Compost Tea Watering?

Hello all, qq on usage of calmag. Reading through all the great threads here, I am able to diagnose I have a slight calcium deficiency and will use some calmag next water. I am using Foxfarm, they have a 1-0-0 solution to apply 1x per month.

For watering, I have been doing an on/off nute cycle, with compost tea in between. I am due for a compost watering tonight, and would like to apply the calmag, but no idea if this is a good thing to try or not.

Alternate would be to wait till next water approx 3-4 days out, letting the deficiency stay, or split the watering where I perhaps do 1/2 compost tea followed by 1/2 calmag diluted water, or vice versa.

Thanks to all who ask and contribute to this great place.


Pictures would be good. More particulars on your grow: for example if in FF soil you likely have another issue than calcium def. Unless deep in flower. So; pictures in white light and details.

What light, what nutes, what TDS of nutes, what PH etc.

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Sorry on my phone.

Happy cannaversary @stltimmy1979

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Here are some of the vitals:
4x8x7 Lite (important due to vertical limitations).
PH 6.5-6.8
Temp - 73 day, 64 night (cold basement trying not to use heater)
Humidity - 60-65 RH
Fox Farm soil and nutrients
Fan - 8" AC Infinity
Strains: GSC, Bruce Banner, and GG

Pics are in the link I posted, having issues on my phone. @Myfriendis410 you mention FFOF ill have another issue other than cal def. Sounds like there is some known issue I haven’t read in any other FFOF related threads.

Removing my situation I am curious at a higher level the issue with FFOF?

What is input TDS and runoff TDS?

Sorry I’m not that sophisticated yet. I’ll try to get a meter when I can.

Can you clarify though on the FFoF comment you made implying it’s common to have issues with that soil other than cal/mag def?

I am only doing half of what df recommends and just the grow as I transition. One water with nutes the next with tea which was my original question.

A number of people were having PH crashing in FFOF.

A decent TDS meter will set you back about $15 on Amazon. Hopefully you have a good PH meter, calibration and storage solutions too. These are the two most used instruments a container-gardener will own. If you supplement, you have to check and adjust.

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If you are not checking ph runoff there’s a possibility that you may have a ph issue in FFOF. Once your ph is out of line it can cause multiple issues.

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Absolutely, got to keep a eye on ph when using OF. :+1:

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Thx all. I didn’t skimp on my water ph meter I got the bluelab pen with all the calibration fluids. I use it to get the nuted water to 6.7. Also use air rocks to add some oxygen.

Here is the pic that prompted the calmag inquiry and has led us to doomsday ph discussions lol. I’m really busy now only
Pic I have is under
Light sorry

I’ll order the meter. So I’m guessing I need to water much more to produce enough excess to get a reading?

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Just ordered this

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@Bulldognuts so looks like I need a lesson in runoff watering. Just researching it now.

Is the basic premise to get the plant over a container, water with nutes at ph, water enough to get excess, then check with this meter?

I’m in five gallon felt pots. I normally am just mixing 2 gallons for 45 total gallons of dirt. Is there a forumla to apply? Should I mix 2x and water till it accumulates in the plastic under my pot?

Then check wi the meter and discard the runoff?

Learning new stuff every hour!!

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You want to water each pot until water drains from the bottom. You’ll want to water slowly and allow it to soak into soil so you don’t have much draining from the sides. Make sure whatever you collect runoff in is free of debris and dirt. I see that you have the plastic style trays, they will work, you just need to find something to set pots on to allow water to flow freely into trays. Also it’s best to keep something under pots to allow airflow under pots, which in turn will allow oxygen to be delivered to the bottom roots. You don’t need a large amount of runoff just enough for bulb of meter to be covered. You’ll want to remove excess water once you get your readings.

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Thank you I appreciate this. I’ll have to find the smallest risers I can, as my lights require a decent amount above canopy and I’m in a smaller vertical tent. I presume there are many on Amazon, as well as discussed on the site, but if you can recommend any I’d appreciate it.

It’s something like this it looks like I could get the benefit of the airflow under the bottom and also get rid of my other plastic runoff containers.

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Or this

You’re looking for between 10 and 20% runoff. Sample the last 1/4 cup of liquid out and use that to determine PH and TDS of effluent. Soil, soilless will sit at different numbers based on how depleted (or not) soil is.

I shoot for 6.0 in everything.