Need help with suspected Mg def

[purrpullkush]

Hey, I have a bunch of plants showing symptoms of Mg deficiency. They were cloned in an aerocloner, since then they've spent 2 weeks in large solo cups filled with straight Fox Farm Ocean Forest. The signs of Mg deficiency have become more prevalent and are starting to worry me. I have been told y many people that FFOF contains plenty of food for early veg if not all of veg and usually I just amend it with mycho and dolomite lime etc, I've also been told that FFOF can burn young plants because its fairly hot right out of the bag.

What I am wondering is, what is causing my mg deficiency?
Could it be that I am watering only with RO water(which I suppose is devoid of the Mg and Calcium that is in tap water)?
Should I spray with epsom salts?
Should I use calmag/magpro etc?
Please advise,
Purrrp

 

[sproutco]

What do the mothers look like the clones were originally taken from? Are they in good health?

 

[purrpullkush]

The mother is very healthy however she was well acclimated to outdoor weather, cheap soil, very very little nutes and straight tap water.

 

[purrpullkush]

but I should mention she does show one possible sign of mg def, a few of her leaves have the sawblade edges curling slightly upwards, however I've been told this is a common trait of the particular pheno I have of this strain. The symptoms showing on the young ones are: Slightly mottled lime green color on older leaves, oldest leaves turning almost completely yellow. Oldest small leaves near bottoms of plant turn COMPLETELY yellow or even rust colored and fall off. Sawblade edges curl up on many leaves. Most main stems fade from green midstem to dark purple almost black near the top. On yellower leaves, petioles are dark purple.
Thanks for the help sproutco

 

[CaptJamesTKirk]

you SHOULDN"T be having def problems after 2 weeks in FF soil - - I'd lean towards watering/ph first. I use and swear by FF, but I add about 40 or 50% pearlite to lighten it up and inprove root growth.

tap water covers a hell of a wide range,, ph fron 5 to 9, and god knows what for minerals/chems.

this is where 1 picture worth a thousand words and a much better diagnosis

 

[purrpullkush]

ahh well I can tell you my tap water comes out at around 9.1ph with tds < 50ppm. So its not bad water but obviously the PH is high. But only the mother plant was receiving this water, and she seemed well acclimated to it. All the kids are getting RO water PH 6.3

 

[purrpullkush]

Hmmm, any other suggestions guys? Much appreciated!

 

[sproutco]

Well if your sure you got magnesium problems, drench with 1/2-1 teaspoon epsom salts per gallon of water. This will not hurt the plants even if you are wrong. This would be about 60-120 ppm magnesium. If you have cal mag plus or something else which is fine just find this rate on the bottle directions and ml you need to use to achieve 60-120 ppm magnesium. You would have to use alot of caution when applying micronutrients for example. Sounds more like root issues than anything. Adjust your ph down to 6 in your water including after adding any ferts. See if a slightly lower ph helps the availability of nutrients.

Here are some alternatives to epsom salts:

Cal-Mag Plus bottle

Quote:
2-0-0
Two tsp (10ml) will achieve a supplement of:
Nitrogen (N) 52 ppm
Calcium (Ca) 83 ppm
Magnesium (Mg) 31 ppm
Iron (Fe) 2.5 ppm
Guaranteed Minimum Analysis
Total Nitrogen (N) 2.0%
1.94% Nitrate Nitrogen
0.06% Water Soluble Organic Nitrogen
Calcium (Ca) 3.2%
Magnesium (Mg) 1.2%
Iron (Fe) 0.1%
0.1% Chelated Iron
Derived From: Calcium Nitrate, Magnesium Nitrate, and Iron edta

So... 10ml/Gal will Yield
N 52
P 0
K 0
Mg 31
Ca 83
S 0
Fe 0
Si 0
+Trace Elements

Sweet bottle

Quote:
0-0-0
Application Rate
10ml of Sweet per gallon of water will achieve 50ppm Magnesium(Mg), 75ppm Sulfer (S), 2ppm Iron (Fe).
Guaranteed Minimum Analysis
Total Nitrogen (N) 0.0%
0.0% Water Soluble Nitrogen
Available Phosphate (P2O5) 0.0%
Soluble Potash (K2O) 0.0%
Magnesium (Mg) 1.5%
Sulfer (S) 2.00%
Iron (Fe) 0.06%
Derived From: Epsom Salt, Ferrous Sulfate
Non-Plant Food Ingredients: Cane Sugar

So... 10ml/Gal will Yield
N 0
P 0
K 0
Mg 50
Ca 0
S 75
Fe 0
Si 0
+Trace Elements

Bottom leaves being affected could be something other than magnesium:



Here is an example of magnesium deficiency. Usually with no brown areas until the leaf gets almost completely yellow.

 

[Guest]

I use ocean forest for seedlings and brand new clones,nothing too "hot" about it at all.When I plant my rootede clones in soil,I use plain water but the next time I'll use a teaspoon of 5-1-1 fish emulsion,they need to eat.I dont know why folks act like ocean forest is almost a preferted soil or something,its defianetly not.I start feeding seedlings at 2-3 weeks about 1/3 strength also but clones need food almost right away.

 

[purrpullkush]

Thats what I'm saying, until this time, I have always fed the young ones with a veg fert like TS 2 part grow etc. I think they may be starving.

 

[Guest]

I thought I was having a mag issue lately in flower. It happens a bit in veg also. The fan leaves near the bottom, and some a little further up...just shrivel and die...with a brown color. It's not too serious...but a concern just the same. I don't notice any yellowing on the leaves at all. No curling up or down. I don't have much yellowing at all...even at harvest time. My plants are just too damn healthy. I still feed N during flower...but not alot.

Any ideas?

Cheers,
SH

 

[purrpullkush]

so, feed N?

 

[Guest]

so, feed N?

It's not an "N" problem. Especially in flower. If it was an N problem...I would see more yellowing of the lower leafs, and in veg I would see lots of opurple stems. This is not the case.

After further investigation...I'm convinced it's a Mg. deficiency.

Cheers,
SH

 

[purrpullkush]

still in veg not flowering, but thanks for info.

 

[CaptJamesTKirk]

tap PH of 9.summtin, is waaaay off

7.0 all the way - I've tried 6.0 and 6.5,,, right back to 7.0.

High PH like that locks out many, many elements.

Fox farms gets cut 40 or 50 % pearlite -- encourages root growth and aireates the soil - - I neve can get pure soil to grow dense roots with clones

 

[purrpullkush]

tap PH of 9.summtin, is waaaay off

7.0 all the way - I've tried 6.0 and 6.5,,, right back to 7.0.

High PH like that locks out many, many elements.

Fox farms gets cut 40 or 50 % pearlite -- encourages root growth and aireates the soil - - I neve can get pure soil to grow dense roots with clones

No, I was saying it comes out of the tap at 9, and with very little salt. I ph to 6.3 usually as recommended by AN.