Fixing Cal/Mag Problems

goodjoint · Dec 9, 2013

After doing a lot of research and contemplating, I think I have some magnesium and calcium deficiencies showing up in my 8 plants. Purple stems, brown spots, yellowing of oldest leaves.
They are clones from the dispensary and I've had them for around 3 weeks. To be honest, some plants showed curled/yellowing leaves when I bought them - I didn't think much of it. (Super Noob Here and My 1st Grow)
Every watering has been done with my tap water (37ppm) + 1/4 to 3/4 strength nutes every other watering.

I decided to foliar spray them with GH CaliMagic (3/4 tsp a gallon) yesterday when they woke up.
My question is... do I need to be feeding them the GH CaliMagic when I water them as well? Or is just the foliar spray enough?
I don't want to overdo it and cause more harm then good.

Also, should I add some dolomite lime to the top layer of the soil to help balance the PH? I didn't know what it was when I started growing and didn't add any to my soil when I planted them

lol.

The Soil PH is low (Around 6.0-6.2) - I think I fucked up and was watering them with too acidic of water? With the soil PH this low, I believe they won't properly absorb Magnesium and Calcium? Am I right?

Strains: (Dispensary Clones) Cheese, Purple Arrow, Mendo Afgoo, Girl Scout Cookies, Blueberry, and Maple Leaf.
Medium: 1 Gallon Smart Pot with 50% Fox Farms Ocean Forest / 50% Perlite
Lighting: 18/6 with 2 x Area 51 XGS-190 LEDs ~18-20" above canopy
Nutes: GH Flora Series - Have only fed 1/4 (220ppm) strength nutes about a week ago. Have given some 3/4 strength nutes.
Watering Schedule: Every 3-5 days - I wait until the pot feels lightweight and the soil is pretty much bone dry. My tap water is 37ppm.
Temps: 72-77 daytime / 64-70 night time
Humidity: 20-40%
Tent: 4x4 Tent
Ventilation: 160cfm exhaust and passive intake / two 6" fans in the corner

Here are some photos of the ladies. Please let me know what you think the best 'next step' should be.
Thanks everyone!!

Devilspawn · Dec 9, 2013

Ph is critical as is not overdoing nutes with youngins. Check the grow problems sticky. Always works for me. I think u have more than ca mg going on there

goodjoint · Dec 9, 2013

Devilspawn said:
Ph is critical as is not overdoing nutes with youngins. Check the grow problems sticky. Always works for me. I think u have more than ca mg going on there

I've checked the stickies. I agree, things don't look right. But out of everything it seems Ca/Mg are the main deficiency since I have been feeding with such low PPM tap water that hasn't had any CalMag in it.

I'm thinking that I need to get the soil PH to 6.5.
Should I do a flush until I get a runoff of 6.5 and wait it out?

dannyboy602 · Dec 9, 2013

goodjoint said:
I've checked the stickies. I agree, things don't look right. But out of everything it seems Ca/Mg are the main deficiency since I have been feeding with such low PPM tap water that hasn't had any CalMag in it.

I'm thinking that I need to get the soil PH to 6.5.
Should I do a flush until I get a runoff of 6.5 and wait it out?

I would add the lime. flush isn't needed

JohnDee · Dec 9, 2013

I'm not a big fan of flushing. That top photo...the bottom leaves show interveinal chlorosis which is classic Mg deficiency. I tend to use epsom salts. 1 tsp/ gal max but go lower at first. Correct your watering ph to a more soil approptiate level...maybe even 7. That's what I'd do to start...
JD

greenlikemoney · Dec 9, 2013

JohnDee said:
I'm not a big fan of flushing. That top photo...the bottom leaves show interveinal chlorosis which is classic Mg deficiency. I tend to use epsom salts. 1 tsp/ gal max but go lower at first. Correct your watering ph to a more soil approptiate level...maybe even 7. That's what I'd do to start...
JD

I couldn't have said it better, good advice,

goodjoint · Dec 9, 2013

JohnDee said:
I'm not a big fan of flushing. That top photo...the bottom leaves show interveinal chlorosis which is classic Mg deficiency. I tend to use epsom salts. 1 tsp/ gal max but go lower at first. Correct your watering ph to a more soil approptiate level...maybe even 7. That's what I'd do to start...
JD

So you think just water with PH 7 water with a 1/2 tsp of epsom salt? Would you recommend foliar spraying this mix too?

JohnDee · Dec 9, 2013

Well that along with your previous feeding schedule. I only use foliar feeding if there's a root absorption issue.
JD

goodjoint · Dec 9, 2013

JohnDee said:
Well that along with your previous feeding schedule. I only use foliar feeding if there's a root absorption issue.
JD

Thanks man! Do you think a touch of dolomite lime to the topsoil would be advisable? Or is the Epsom Salt enough?

Nizza · Dec 9, 2013

listen to dannyboy

that ocean forest is buffered with powdered oyster shell!
you added 50% perlite, so now you water twice as much, and the medium is twice as not buffered (buffered half as long)
and probably even less time cause now we water more cause of perlite!

so what happens is all the oyster shell is washed out, throwing off pH and locking things out.. throwing down the pH was my experience, at 4.8 runoff from anything i put in.
all leftover nutrients that are packed in didn't wash out, this is whats now buffering the pH down to 4.8

you could've added lime into your soil when mixing, or as dannyboy said, water it in now, almost guarantee the forest has plenty of cal-mag in it, nevermind your tap water is such a low ppm when you hit it with plain water its also leeching valuable nutes out with the runoff. this is a way of shocking it.

sure your water has a low ppm, try doing 1/4 dose rec. epsoms and full dose rec. lime

or do a flush until runoff water reads the same as water added in, this takes a while
and then the last watering go half strength nutes full strenth cal mag, and watering after go full full, then back off and go full again, and so on (until you taper off for harvest)
PH after flush should always be around the same as water put in.

if you check runoff water (make sure you do a very slow runoff check..) you can take the ph out and ph in, and change what your next ph in is..
say you do a watering that goes in as 8 and out as 7, you could say the pH of soil is around 6
so if you are watering with 7 and you get 6, next time you could probably go 7.5 to achieve your 6.5 goal, is how i understand the soil ph game.
just know that things in the soil effect the pH and as dannyboy said, easiest route is lime because it will change everything to 7 and no more pH issues.

read the bag of ocean forest so you can help yourself understand whats doing what in the soil. you could try next time adding 50% perlite and a 2/3 dose of lime to it or something

goodjoint · Dec 9, 2013

Thanks so much for your advice.
Sorry, but what is rec. stand for? (rec. epsoms, rec. lime)
The water I've been feeding is 6.8. It comes out of the bottom of the pots at 6.0-6.2.

Nizza said:
listen to dannyboy

that ocean forest is buffered with powdered oyster shell!
you added 50% perlite, so now you water twice as much, and the medium is twice as not buffered (buffered half as long)
and probably even less time cause now we water more cause of perlite!

so what happens is all the oyster shell is washed out, throwing off pH and locking things out.. throwing down the pH was my experience, at 4.8 runoff from anything i put in.
all leftover nutrients that are packed in didn't wash out, this is whats now buffering the pH down to 4.8

you could've added lime into your soil when mixing, or as dannyboy said, water it in now, almost guarantee the forest has plenty of cal-mag in it, nevermind your tap water is such a low ppm when you hit it with plain water its also leeching valuable nutes out with the runoff. this is a way of shocking it.

sure your water has a low ppm, try doing 1/4 dose rec. epsoms and full dose rec. lime

or do a flush until runoff water reads the same as water added in, this takes a while
and then the last watering go half strength nutes full strenth cal mag, and watering after go full full, then back off and go full again, and so on (until you taper off for harvest)
PH after flush should always be around the same as water put in.

if you check runoff water (make sure you do a very slow runoff check..) you can take the ph out and ph in, and change what your next ph in is..
say you do a watering that goes in as 8 and out as 7, you could say the pH of soil is around 6
so if you are watering with 7 and you get 6, next time you could probably go 7.5 to achieve your 6.5 goal, is how i understand the soil ph game.
just know that things in the soil effect the pH and as dannyboy said, easiest route is lime because it will change everything to 7 and no more pH issues.

read the bag of ocean forest so you can help yourself understand whats doing what in the soil. you could try next time adding 50% perlite and a 2/3 dose of lime to it or something

JohnDee · Dec 9, 2013

Nizza wrote: try doing 1/4 dose rec. epsoms and full dose rec. lime

Seems reasonable. The Mg from the Epson salt will be immediately available and the lime will be a longer term preventative.
JD

Nizza · Dec 9, 2013

rec=recommended lol sorry i always spell it wrong for some reason, its just that word i can't spell right without seriously thinking about it..

i guess i said it backwards too lol dose recommended... not high enough i guess
not like it has to be epsom either you can use your gh liquid stuff

cal mag won't be needed if using a "complete " nutrient system i use dyna gro foliar pro as a 1-part veg and bloom nute, and has enough cal-mag in it for flower and veg. You can read your nutes and compare with the amount of cal-mag and dosages for foliar pro with whatever nute system used and figure it out
since i grow in coco that grabs out some cal mag so i add a little extra cal mag in conjuntion with the foliage pro each watering. coco is a whole nother game though

JohnDee · Dec 9, 2013

Goodjoint,
And just to clarify the lime issue...in gardening Dolomite lime is used for it's buffering as well as adding both Calcium and Magnesium. Natures calmag...
JD

goodjoint · Dec 9, 2013

Nizza said:
rec=recommended lol sorry i always spell it wrong for some reason, its just that word i can't spell right without seriously thinking about it..

Haha no prob, I really appreciate your help!
I'm about to go to the Hydro store and pickup some Epsom Salts and Lime to mix with my water. Should I add my regular nutrients after I mix up the lime and epsom?

goodjoint · Dec 9, 2013

JohnDee said:
Goodjoint,
And just to clarify the lime issue...in gardening Dolomite lime is used for it's buffering as well as adding both Calcium and Magnesium. Natures calmag...
JD

Okay thanks for the clarification. So DON'T use it along with the CalMag?
A couple days ago I sprayed the leaves with a mist of 3/4 dose of CalMag... will the added lime/epsoms that I plan on water feeding today affect it negatively cause of this?

acellular · Dec 10, 2013

No...but don't go to crazy with the cal mag feedings. I'm sure if you checked your ppm's your probably sky high and it's all calcium and magnesium. Less is always more! For foliar feedings 3/4 dose is too strong. Go way less than reccomended for foliar feeds.

Devilspawn · Dec 16, 2013

Sorry been off for a week. Low Ph stops ca mg absorption. It's really morenon a channel issue so I would worry more about growth media and getting ph up. I use hydro n had my Rez drop to below 5.4 n it reeked havoc in just a few days. Chlorosis, brown spots, stunted height.... Once ph back in range new growth looked great

Fixing Cal/Mag Problems

goodjoint

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