Magnesium deficiency?

selfmedicator462

selfmedicator462

Well-Known Member
I think I developed a magnesium deficiency. The last few grows have done this late in flower. I already use calmag and pk booster that has mg in it. I started foiliar feeding an Epsom salt solution and gave it a shot of calmag this morning to help the problem. In starting on week 7 of flower so it's kinda late. I grow in soiless pro mix, ro water, hydroponic research veg n bloom nutes. I oh between 6.8-7.0. I know it seems high but they seem to like it there with this growing method. image.jpeg
 
polishpollack

polishpollack

Well-Known Member
if you have 3 applications of mg, then it's not mg def, but what you do appear to have is over fert. that yellowing of the leaf tips and browning usually mean over fert. just pics in white light in the future. are you feeding fert pretty frequently, or is the soil already loaded with fert?
 
selfmedicator462

selfmedicator462

Well-Known Member
Im using soiless promix as a medium therefore I need to feed with every watering. If you just water it rinses the nutes out of the medium. When I feed i always have plenty of runoff. That pic is with the lights off.
 
VTMi'kmaq

VTMi'kmaq

Well-Known Member
well at the very least you can be appreciative of the fact this is happening close to the end of life as oppossed to the start of it. Have you thought about maybe adding rock dusts next grow? Oh shit thats right your soiless......huh i'm stumped mon. Regardless of the issue the plant still looks great man
 
selfmedicator462

selfmedicator462

Well-Known Member
I can't go that low of a ph with soiless or it locks out. I have to keep it high around 6.7-7.0. I don't use a res. I have a 5gal smart pot filled with pro mix and perilite. About every 3 days I feed/water with about 3 gallons of water which gives me a decent runoff. I'm feeding at 900ppm right now. Plus a pk booster and calmag. I wonder if I shouldn't start cutting back on base nutes when I get late into flower? More or less just wanting to figure this out for my next grow. This one should be done this week. Which is good cause I've been smoking nothing but pennywise for the last 2 yrs.
 
tropicalcannabispatient

tropicalcannabispatient

Well-Known Member
selfmedicator462 said:
I think I developed a magnesium deficiency. The last few grows have done this late in flower. I already use calmag and pk booster that has mg in it. I started foiliar feeding an Epsom salt solution and gave it a shot of calmag this morning to help the problem. In starting on week 7 of flower so it's kinda late. I grow in soiless pro mix, ro water, hydroponic research veg n bloom nutes. I oh between 6.8-7.0. I know it seems high but they seem to like it there with this growing method. View attachment 3542886
Click to expand...
Nutrient Problems with Pictures - Cannaversity http://www.cannaversity.com/cannaversity/article.php?id=057
 
tropicalcannabispatient

tropicalcannabispatient

Well-Known Member
selfmedicator462 said:
I think I developed a magnesium deficiency. The last few grows have done this late in flower. I already use calmag and pk booster that has mg in it. I started foiliar feeding an Epsom salt solution and gave it a shot of calmag this morning to help the problem. In starting on week 7 of flower so it's kinda late. I grow in soiless pro mix, ro water, hydroponic research veg n bloom nutes. I oh between 6.8-7.0. I know it seems high but they seem to like it there with this growing method. View attachment 3542886
Click to expand...
 

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SnaFuu

SnaFuu

Well-Known Member
bird mcbride said:
And swing your res between 5.5-6.2ph. If you don't you're gonna get lock out.
Click to expand...
This is nonsense. Read the thread before posting.

selfmedicator462 said:
I think I developed a magnesium deficiency. The last few grows have done this late in flower. I already use calmag and pk booster that has mg in it. I started foiliar feeding an Epsom salt solution and gave it a shot of calmag this morning to help the problem. In starting on week 7 of flower so it's kinda late. I grow in soiless pro mix, ro water, hydroponic research veg n bloom nutes. I oh between 6.8-7.0. I know it seems high but they seem to like it there with this growing method. View attachment 3542886
Click to expand...
Not sure the cause of your problem but I'd like to mention your soilLESS medium is closer to hydroponics than soil. Any feed or water going in should be at a lower ph than soil. 5.8 - 6.0 is conventional.

I use amended promix and 5.8 works great for me. Also I feed - water - feed - water.

However looking at the lockout charts, MG should still be getting absorbed at your ph range so I am stumped. Perhaps a bit of salt build up, could try watering between feedings like me.

Regardless, nice job on the scrog. :clap:
 
polishpollack

polishpollack

Well-Known Member
Now that more info has come out, it looks like some over fert with perhaps excessive watering. I'm guessing at the watering part because I'm not there and can't see the soil after three days to see how dry it might be. are you sure that promix requires much fert? my knowledge of promix is that the factory puts fert in their soils, except for those that are designed for seedlings. but then I don't use promix and this is based on an email I received from the company years ago when I asked them the difference between their soils. it still looks like over fert with green leaves and dying leaf tips, which usually indicates over fert. If you're at 900 plus booster then is your real ppm considerably higher? 900 still sounds like a lot of fert for a soil grow, not for hydro though because with so much water, there's a high dilution rate. I'd stop the ferts since you're almost done and see how they do, especially since you're so close to finishing.
 
selfmedicator462

selfmedicator462

Well-Known Member
This promix isnt soil. Its just peat moss and perilite. With a 600 watt HPS my temps run around 80-84 degrees. Usually around 72 at night. That and this is a large plant it dries out in about 3 days. The stem is at least 1.5" in diameter. I check it once in a great while with a moisture meter and it drops to about 0.5 or less in 3 days.
 
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selfmedicator462

selfmedicator462

Well-Known Member
SnaFuu said:
This is nonsense. Read the thread before posting.


Not sure the cause of your problem but I'd like to mention your soilLESS medium is closer to hydroponics than soil. Any feed or water going in should be at a lower ph than soil. 5.8 - 6.0 is conventional.

I use amended promix and 5.8 works great for me. Also I feed - water - feed - water.

However looking at the lockout charts, MG should still be getting absorbed at your ph range so I am stumped. Perhaps a bit of salt build up, could try watering between feedings like me.

Regardless, nice job on the scrog. :clap:
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Ive tried it at that PH and had bad results. In my journal you can see the results early on of using the low PH. It wasnt taking in the nitrogen at all. Bump it up to 6.9 or so and everything is golden. Its been that way since my very first grow. Not sure why. If its the medium. My water. My nutes. not sure.
 
Extrome

Extrome

Well-Known Member
I'm seeing dark green on the bottom, lots of extra shine and leaves curling down like claws. How much Nitrogen you feeding them? N toxicity can lock out Mag and I think that's what we're seeing here.
 
polishpollack

polishpollack

Well-Known Member
bird, it's a soil grow. 5.5 pH is too low for soil. you don't really need to aerate a nute mix before watering, although that may not be a bad idea. you usually you let the soil dry out between waterings. and this statement you made about older plants being subject to root burn isn't right as root death would be due to high fert content, not root mass size, unless you're saying that more roots come into contact with more fert, which isn't really the case. root mass size doesn't equal burn. so you're getting your info from where?
 
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