What do you think is causing this?

I run silicate in low dose in my hydro unit every second res change in soil it is always there


@Donaldj at what point would you add silica to coco?

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treat it like hydro

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Guys sorry to barge in like that, u need your opinion on this urgent matter!! Am attaching a few pics, its an outdoor grow, ph at 6.5, evthg was great until one of the plants started showing yellowing leaves from the inside out of the leaf, it started with fan leaves and its progressing bottom up and to the other bud leaves…:cry::cry:, its a diesel plant and it seems that a second girl (jack flash) is following her lead, we are early 3rd week of flowering, heeelp!!!


Mag def I answered on your other post epsom salt works some strains really love mag :wink:


Just hit it with some calmag? @Marcos666

I got today some calmag but the shop didnt have it in liquid form, he told me it was water soluble but he wasnt sure, its white pellets, do u have an idea if my plants can use it if i try to dissolve them in water. Am asking this bcz i got some calcium nitrate in solid white small shunks and i was told that even if i dissolve in water they wont be available for the plant before 6 months, any thoughts??
So to be on the safe side i got the only liquid calcium form he had that is Calcium with Boron that can be sprayed, also some solid magnesium phosphate (epsom salt ) to apply them in case the solid Calmag wasnt soluble and usable for my plants, what do u think
Ok guys i just my research and found my calmag is water soluble so my question is should i apply it on the leafs by spraying it ( knowing that some plants are in 4 th week of flowering) or in the water used to water them? would the nitrate present in my calmag disrupt my nutes ration? How much calmag should i dissolve per liter of water?

I guess I am kinda spoiled in that I haven’t had to use Calcium in powdered form so as far as dosing I would suggest you water it in nutrients on leaf surface can easily burn your plants @garrigan62 @latewood would be better advisors since it is commercial format for larger farms :wink:

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Magnesium Deficiency


Magnesium helps supports healthy veins while keeping a healthy leaf production and its structure. Magnesium is significant for chlorophyll-production and enzyme break downs. Magnesium which must be present in relatively large quantities for the plant to survive, but yet not to much to where it will cause the plant to show a toxicity.

Magnesium is one of the easiest deficiencies to tell… the green veins along with the yellowness of the entire surrounding leave is a dead giveaway, but sometimes that’s not always the case here. In case you have one of those where it doesn’t show the green veins, sometimes leaf tips and edges may discolor and curl upward. The growing tips can turn lime green when the deficiency progresses to the top of the plant. The edges will feel like dry and crispy and usually affects the lower leaves in younger plants, then will affect the middle to upper half when it gets older, but It can also happen on older leaves as well. The deficiency will start at the tip then will take over the entire outer left and right sides of the leaves. The inner part will be yellow and or brownish in color, followed by leaves falling without withering. The tips can also twist and turn as well as curving upwards as if you curl your tongues.

Excessive levels of magnesium in your plants will exhibit a buildup of toxic salts that will kill the leaves and lock out other nutrients like Calcium (Ca). Mg can get locked out by having too much Calcium, Chlorine or ammonium in your soil/water.
One of the worst problems a person can have is a magnesium def caused by a ph lockout. By giving it more magnesium to cure the problem when you are thinking you are doing good, but actually you are doing more harm then good. When the plants can’t take in a nutrient because of the ph being off for that element, the plant will not absorb it but it will be in the soil… therefore causing a buildup. A buildup will be noticed by the outer parts of the plant becoming whitish and or a yellowish color. The tips and part way in on the inner leaves will die and feel like glass. Parts affected by Magnesium deficiency are: space between the veins (Interveinal) of older leaves; may begin around interior perimeter of leaf.

Problems with Magnesium being locked out by PH troubles

Light Acid Soils, soils with excessive potassium, calcium and or phosphorus


Magnesium gets locked out of soil growing at ph levels of 2.0-6.4
Magnesium is absorbed best in soil at a ph level of 6.5-9.1 . (Wouldn’t recommend having a ph of over 7.0 in soil) anything out of the ranges listed will contribute to a Magnesium deficiency.

Hydro and Soil less Mediums

Magnesium gets locked out of Hydro and Soil less Mediums at ph levels of 2.0-5.7
Magnesium is absorbed best in Hydro and Soil less Mediums at ph levels of 5.8-9.1
(Wouldn’t recommend having a ph over 6.5 in hydro and soil less mediums.) Best range for hydro and soil less mediums is 5.0 to 6.0. Anything out of the ranges listed will contribute to a Magnesium deficiency.

Solution to fixing a Magnesium deficiency
Any Chemical/Organic nutrients that have Magnesium in them will fix a Magnesium deficiency. (Only mixing at ½ strength when using chemical nutrients or it will cause nutrient burn!)
Other nutrients that have magnesium in them are: Epsom salts, which is fast absorption. Dolomite lime and or garden lime (same thing just called different) which is slow absorption. Sulfate of Potash, Magnesia which is medium absorption. Worm Castings, which is slow absorption. Crabshell which is slow absorption. Earth Juice Mircoblast, which is fast acting. (a must buy!! Has lots of 2ndary nutrients).
Now if you added to much chemical nutrients and or organics,( which is hard to burn your plants when using organics) You need to Flush the soil with plain water. You need to use 2 times as much water as the size of the pot, for example: If you have a 5 gallon pot and need to flush it, you need to use 10 gallons of water to rinse out the soil good enough to get rid of excessive nutrients.

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Wow thank u guys, that was really helpful
Am heading out now to give them the calmag
My soil ph is around 6.3 but from what ive read Mag gets locked out by a ph inferior to 6.0
Any comments ok that?


Hey @Marcos666 just Google cannabis nutrient uptake chart. I’ve seen two or 3 charts that say calcium is absorb in the pH range of 6. I don’t use soil though I set my pH to 5.8 or 5.7 in hydro and left it drift up to 6.5. Usually by the time it gets past there I am flushing and adding new water + nutes. Which usually puts me back at 5.8 again.


@garrigan62 thanks for the assist my friend

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Thanks guys, i supplemented with calmag, nutes, rhino skin, big bud, piranha and sprayes also some magnesium (bud factor x) wich i all got fromna friend :yum: And now waitin n hoping for the best.
But i want to have ur opinion on other 4 girls that i had planted directly in the soil, since they went into flowering 20 days ago they didnt seem quite thriving, thin small leafs ( even for a sativa), and now that the flowers are really showing i noticed some pistils dying off ( white hairs) not too much but still it seemed unusual, then today i noticed on the lower leaves the same discoloration that u pointed out as magnesium diffeciency, since its rare to have magnesium defficiency outdoor how come i have it in all my plants?? The ph ranges from 6.1 till 6.7 beteen the plants… my nutes contain traces of magnesium, am attaching some pics,