4 Week Vegetative - Iron Deficiency? -Auto flower- help

This is my Third grow, second with Auto Flowers.
These babies sprouted 4 weeks ago,
they are Think Different Auto flowers,
growing outdoors in 6L pots, filled with 'osmocote, Potting & Planting mix' (6 month feed, manure, blood & bone, Seaweed, fish, gypsum) mixed with perlite.

The weather was quite cold and rainy the first 2 weeks, in Melbourne, Australia, this whole week has been full sun for 8 hours ~20 degC humidity ~50%.
Watering only once / three days when sunny.

I noticed yellowing of the the top leaves, and now new leaves are also yellow, veins are more green. (started just over a week ago)
I did a flush 3 days ago. (about 2-3x pot volume natural PH)

Soil meter reading is about PH 6.5




In the photo, the plant behind the one suffering has had the exact same treatment (bar the flush) with the same PH reading.

Please let me know if the yellowing is due to an Iron (Fe) Deficiency, if it is what can I do about it so early in its growth.
Should I be attempting to increase its acidity? (lower PH) in order to improve the Iron uptake?

Thanks in advance!!

-FunkeDutch

Has one been in the sun more than the other, are you sure the yellowing one is not drowning, check the plug holes to ensure the water is running off. Doubt you will have a deficiency if both in same soil and one is ok. PH is okay. They are both small for 4 weeks, cold weather would not have helped. I'd guess maybe soil too wet, check water is running out of pot.

Hi Funkedutch,
I'm not really sure...never run into it. But I looked up a few links and it said interveinal chlorosis and yours is more generalized.

http://www.cannabis.com/growing/sick_plant-iron_FE_deficiency.html

Might be a broader nutrient lockout. Nemotodes, excessive soluble salts, etc (see link)

Personally I'd be thinking to transplant up early with some milder soil. Time-release stuff scares me because once it's in the soil...it stays there. No flushing can remove it. But by surrounding it with some no-nutes ph tested mild soil...the roots can get some relief. Just a thought...
JD

spliffbuddy said:

Has one been in the sun more than the other, are you sure the yellowing one is not drowning, check the plug holes to ensure the water is running off. Doubt you will have a deficiency if both in same soil and one is ok. PH is okay. They are both small for 4 weeks, cold weather would not have helped. I'd guess maybe soil too wet, check water is running out of pot.

Click to expand...

They have both been in the same location so it shouldn't be due to environmental impacts.
Drainage is good. Though, it did get quite a bit of rain at one point, it rained so much that I put them under cover.
I will keep the soil moisture on check and see if the issue gets better.

JohnDee said:

Hi Funkedutch,
I'm not really sure...never run into it. But I looked up a few links and it said interveinal chlorosis and yours is more generalized.

http://www.cannabis.com/growing/sick_plant-iron_FE_deficiency.html

Might be a broader nutrient lockout. Nemotodes, excessive soluble salts, etc (see link)

Personally I'd be thinking to transplant up early with some milder soil. Time-release stuff scares me because once it's in the soil...it stays there. No flushing can remove it. But by surrounding it with some no-nutes ph tested mild soil...the roots can get some relief. Just a thought...
JD

Click to expand...

Its always hard to know for sure with these symptoms, (unless you have run into them many times) you are right, the new leaves definitely aren't showing very green veins.
I have used the same soil two times before and had been okay, last time though I had a higher ratio of no-nute soil mixed in with the seeding pot.

I don't have anything to test salinity but will look into it.

I wasn't actually planning on transplanting these, I should have gone one size up to the 9L (2.5 Gal) pots to begin with.
I wanted to experiment what the Autos yield in smaller sized pots.

Thanks for your suggestions.

Guys, she hasn't grown at all, leaves are looking worse.
I need help otherwise I might just pull her out and start another seed,
or experiment with random nutes ruining the soil.



Its been a week since flush.

On a good note that other Think Different is doing really well, stalk is quite significant for its age!

Please someone help me nurse the other one back to health, I know that will all the experience on here someone has has this before.

-FunkeDutch

FD,
Did a little research... sulphur deficiency can cause similar appearance. If you agree, best and easiest solution is to use epsom salts. You can get it at a pharmacy/drug store. Same stuff you soak a sprained ankle in. MgSo4 so it adds Mg too. Little risk. Start with 1/4 tsp/gal and ph correct. You can go to a max of 1 teaspoon per gallon. It's a little hard to dissolve so stir a lot...or use warm water.

That's my best guess dude...
JD

Phosphorus toxicity, and Potassium toxicity will lock out Iron.
IMO- It does look like and (Fe) Deficiency, Yellowing starting at the end of the Petiole extending out to the tip of the plant.
IMO- your plants to young to have a deficiency going on.

Look at this link and see what you think...

http://www.ilovegrowingmarijuana.com/marijuana-nutrient-deficiency-sulfur/

ur ph is good
I have an inkling ur gonna have to start over on the one.
new growth like that is a bad sign. also...if u start over toss the soil out don't reuse it

Maybe hit it with a vegging nute at half stregnth, give it a day or two........and if there is no visible difference by the second day, do it again........at half stregnth........until you see a difference in the yellowish growth in the middle of the plant.

Thanks for all the replies today,

JD thanks for the effort, the descriptions from article you linked do sound pretty close to the symptoms.
I have some Epsom Salts already so Ill give it a go, that way if it is sulphur or magnesium deff wed soon find out.

Topfuel, thanks for the reference chart, I hadn't seen that one with all the symptoms on one page.
It sounds like you agree with me on the Fe deff but you also cant see why it has this problem so early in vegetation (still with Cotyledons intact).
So maybe its a lockout of some kind or a bad root system I haven't a clue.

Danny, thanks for dropping by.
I agree that this will have an effect through the rest of its growth, if the above attempts fail I will remember what you said and throw out the soil.

After the last post I loaded her up with Epsom salts, just to see what would happen.
In the end she did survive and is growing. I don't expect to get even a popcorn bud out of this plant, just curious to see how it developed.