I have a question about cal/mag and soil.

#1cheesebuds · Oct 21, 2015

IM using a 200 watt LED COB light and my lady is looking ok for now. she is now 7 weeks flowering full sativa. Should I be adding some cal/mag the soil? I ask because some of the leaves are starting to look a lil bit yellow and I was planning on flowering her to week 12-14 to get full ripeness.

your opinions please.

ExEcutioner · Oct 21, 2015

dont confuse it. That yellow could be a mg or low phos or low k or needing a repot. u dont have a calcium problem.

worry about ur ph first.

and no please dont use cal mag in your soil..... know where your ph is, move from there.

#1cheesebuds · Oct 21, 2015

my ph is around 6-7. is this a good ph or does it need to be higher or lower? I been feeding her bloom botanicare pure bend pro and molasses. The problem is probly poor soil. I got better soil for next time.

SwampyTHC · Oct 22, 2015

Try run between 5.8 .6.2 I sometimes allow it to get to 6.3 then bring it right down just before chop is the yellowing on whole leaf tips or outer edges you could need to bring ph down If you're at 7 that's far too high....as executioner says work from your ph first before adding anything

ChasingGreen · Oct 22, 2015

I run into the same issue and I've found that adding calmag will help. However, the symptom of a cal def is spotting, not yellowing. If you're yellowing, it's nitrogen most likely. Sounds like your ph is fine. My ph is right at 6.3 and I have cal issues from week 5 on with my current strain, drives me nuts so I've been trying to up the calmag to the correct level for future runs.

ExEcutioner · Oct 23, 2015

SwampyTHC said:
Try run between 5.8 .6.2 I sometimes allow it to get to 6.3 then bring it right down just before chop is the yellowing on whole leaf tips or outer edges you could need to bring ph down If you're at 7 that's far too high....as executioner says work from your ph first before adding anything

Thanks Swampy. he'll get it turned around nice.

Tonygreen · Oct 23, 2015

be careful about adding nitrogen well into flower, it can stunt flower growth. Can you put a pic up of em?

SwampyTHC · Oct 23, 2015

No probs executioner I wouldn't even bother adding any nitrogen in at this late stage just bring your ph down you said you were running 7 that's waaaaay too high my friend. Don't forget to keep us updated on the resolve bro

ganjygav · Oct 23, 2015

I've only just started to ph in soil because I never thought I needed to with soil but I was getting lockouts big time. This is the chart I used to remedy my problems. It shows the lowest cal and mag can be absorbed is at ph 6.5. So I've been adjusting my water to 6.5. Am I right? It's just I see some people here suggesting lower ph for soil. My water was at 7.8 to 8.0 ph.

Floridian · Oct 24, 2015

6.5 is just perfect for soil.Forgive me if I missed the most important question to be asked in your situation.Are you using R/O water?If you are then yes you should use 5 ml or 1 teaspoon per gallon water.

#1cheesebuds · Oct 24, 2015

IM using a brita water filter to filter tap water. then I add the bloom food then check to make sure the PH is good then water the plant. but really I think this plants problem for this round is do to the bad hard SOIL.

SO I have way better softer soil with lots of worms in it for the next round.

Cork144 · Oct 26, 2015

How much perlite do you use bud? been some time btw good to see your still on here and holy shit nearly 6k posts you spammer lol.......

I use garden center cheap soil, 120L for £8 lol, but I use it 2/3rds soil 1/3rd perlite ATLEAST and have never had compact soil issues

Floridian · Oct 28, 2015

Forget shita filters,r/o units are inexpensive and will make such a difference in your grows that it will explode your head.

early_bird · Oct 28, 2015

Watering with a certain PH does not always lead to the desired target PH in your soil.
Because PH Buffer capacity should be considered.

For example your soil is quite acidic, let´s say PH 5,5
If you water with PH 6,5 the buffer of the soild leads to low PH Level of may PH 5,65 or anything else between 5,5 and 6,5.
This can happen if you have lot of turf in your soil for example, here i have seen even PH 4,x in the past after watering with PH 6,5 water a PH 5,6 soil!

What to do ?
Just keep watering with your raw tap water without PH correction here, let´s say 7,5 for example. If you want a certain PH in your soil, it doesn´t mean that you should water always exactly with that PH value.
Any other recommondations here are welcome.

Not even considered the possibility to lower or rise PH through fertilizing. Biologial fertilizers can affect PH of your soil for example.

Tonygreen · Oct 29, 2015

great post early bird. we must tread carefully when treating our soil like hydro!

traditional use of dolomite lime is an example, it helps the buffer capacity of soil.

Floridian · Nov 23, 2015

Dolomite is a dolomust especially with acidic soil like promix.Use a tablespoon a gallon with that.I use around a teaspoon per gallon with my mixture of ocean forest and roots.

frostqueen · Nov 23, 2015

Floridian said:
Dolomite is a dolomust especially with acidic soil like promix.Use a tablespoon a gallon with that.I use around a teaspoon per gallon with my mixture of ocean forest and roots.

Promix isn't really very acidic. It already has limestone added, ph of 5.5-6.5, but I find it at about 6.2 usually. I use HP. The BX is also pre-limed and at 5.5-6.5. Sunshine #4, however, is usually in the 4.5-5 ph range. I used to use that but bailed after trying the PromixHP, then stopped liming altogether. Great stuff.

https://hort.purdue.edu/hort/facilities/downloads/proMixHP.pdf

https://hort.purdue.edu/hort/facilities/downloads/proMixBX.pdf

Not that OP is asking for soil recipes, but 50% Ocean Forest mixed with 50% ProMix HP is a fantastic medium with a great texture and ph... I don't personally prefer any runoff, but if you do you could always try 1/3 OF and 2/3 PromixHP.

This soil mix has enough nitrogen in it (the OFO) to carry you through week 6, at which time you usually want it to start being depleted. A long-running sativa might need a small N bump at the end of week 6 to carry it to week 10 or longer.

bigAl25 · Nov 23, 2015

Tony nailed it. I always add dolomite lime in my organic soil when I up pot for late veg and flowering. Not a whole lot but around 1/10 of the volume of soil and perlite mix. Promix is usually a great choice for soil.

Mikell · Nov 24, 2015

Crazy it's gotten this far without a picture or vivid description.

Terpene · Nov 24, 2015

LEDs will suck the magnesium out of your plants. I had this problem with just about any soil I ran, in large containers, amended, you name it.

The solution is a spoonful of epsom salt in a gallon of water, sprayed foliarly. Enjoy! :tiphat:

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