magnesium deficiency???

[yankee]

hello guys.. I got this this here flowering plant that i thought had lack of magnesium. but after three weeks of epson salt treatment it only seems to be getting worse.

What type of medium; soil or hydro? Soil
What brand and type of soil? 3g blend from local hydro store,
Indoors or outdoors? indoor
What strain? g13xWW
How old are the plants? 65-70 days
What type of lights and how many watts? 400w HPS
How far from the lights? 3 1/2 feet
What, how much and when was it fed? NPK? Old Grow organic Bloom food,recommended dose, once a week 5/15/10
What is the medium/runoff pH and PPM if in hydro? ph is 6.8 in soil
What are the temps and humidity in the room? 35C is max ( i know it is hot) 60%RH
What size pots? 1 gallon grow bags
Any bugs? Look real close. no bugs
Any other pertinent info? I dont have but 4 plants, but all 4 are showing these symptoms. Also I am using well water. The trichomes seems to be large and abundant but i still don't like seeing my girls hurting..

[katana2k9]

it does look like that i had a simular problem but i just gave it tomatoerite its organic and with mag, and cleared it up straight away, just flush with Ph balanced water, best way to do this is boil water(let it cool) 4 times the amount of your pot size and flush, leave it for a week or so once it looks better and go back on the nutes at 1/4 dose have you got a pic of the whole plant ?

[yankee]

I can take a pic of a plant.. I will post back tonight

[katana2k9]

cool yankee ill have a look then for you and ill be able to tell what going on by looking at the plant

[yankee]

I wasnt able to get any pictures last night, work got me tied over... Anyways there are some leaves that have totally died, while others mostly have those "rust spots"on the leaves. It is not spider mites ( i have had those years ago, what a bitch)... anyways i think this is just simple magnesium deficiency... I will post a pic of a plant when I can get one...

[community]

My plants had a really similar problem almost IDENTICAL and I discovered that it was a low pH problem/over fertilizing. pH was the biggest problem because it was at a 5 and I was having nutrient lock out. My nitrogen was really high too.

I concluded that the pH problem caused a lock out of phosphate and magnesium and manganese. They all look really similar and all fall in the same pH range of lock out.

My advice is to flush and re-nute in a couple of days. I would also check the NPK of the soil using a chemical titration test kit. Check the calibration of your pH probe. Test it against pure distilled water, which should be a 7.

While electronic pH probes are precise, I used a simple chemical titration to test pH, which are more accurate then electronic pH probes.

[yankee]

I will check that out with some distilled water, otherwise I have an electronic PH tester and it shows around 6.8. I will post a picture my girls tomorrow night that will hopefully help you guys get a better feel of what I got going on.. I thank you for your replies!!

[SexyStaci]

I agree with community, Low PH. Check the water run-off of the soil. Low ph will lock out magnesium and mimic a magnesium deficiency. It happened to me too.

[yankee]

well you guys got me thinking... Ive got a few things to try tonight. First, check my ph meter in distilled water, which should be a 7.. Once that is completed i will proceed to check the soil run off. I will post back tonight with my results. I am going to try and get a picture of a entire plant too..thanks

[stoney4life]

Let us know what you find out because Ive had 2 crops of clones with the exact same problems. I think that its ph lockout because I made sure to feed plenty of CalMag on my second crop and it still did it. I only use the little ph tester drops so thats why I am leanin towards ph lockout.

[SexyStaci]

Next grow add 1-2 tbsp of Dolomite lime per gallon of soil to your mix. I'll bet you won't have that problem again.

[yankee]

Originally Posted by SexyStaci

Next grow add 1-2 tbsp of Dolomite lime per gallon of soil to your mix. I'll bet you won't have that problem again.

I will be sure to try that.. I am to understand that lime will raise my ph? I have some chemical ph UP, do you think I should try some on my girls that are left?

[SexyStaci]

I would.

[IGotTheCottons]

Originally Posted by yankee

I will be sure to try that.. I am to understand that lime will raise my ph? I have some chemical ph UP, do you think I should try some on my girls that are left?

Check to make sure your PH meter is reading properly, first. If your PH really is 6.8, you don't want it going much higher than that.