New leaves coming in yellow

i have a couple new plants, almost a month from seed.

all of them have new leaves that are coming in bright yellow.

for 2 of the good plants, they stay that way and end up turning a light green.

for the leggy plant, the leaves droop and they are starting to get dirty brown spots on them, looks like dirty water spots almost.


i want to figure this out before my healthy (looking?) plants start to get the spots


help please!!

They look overwatered... and they could do with some nutrients. NPK.

man, im glad you hopped on this thread. i need soem reputable help


they are getting nutes and water, actually they are in an aerogarden

started at 1/4 strength with Advanced Nutrients: Vitaboost Pro , they are now at reg. strength

Is your PH ok? If they getting full strength nutes, then most likely your ph is off causing an imbalance, and making it hard for your roots to uptake nutes.

Have you looked at the roots? If they look brown and mushy, this could also be the reason... and means light is getting to them, or they are too warm and pathogens have been cultivated that will feed on your roots.

the roots look pretty good. although, some of the older ones are not as bright of a white, but for the most part they are good.

pH is actually pretty solid, been at 5.8-6.0 all the time, very stable. thought that was the inital problem, ive checked at least 3x daily and its good.

if i can get some pics of the roots ill post them on here- at work not, wont be til later this afternoon.

i wouldnt say the roots were brown tho...

my inital thought was Mg deficiency.

my water is pretty hard - <200 ppm, around 192 typically.
so i thought that the Mg and Ca were being locked out. i was foliar feeding early am and late pm with a solution of 1/2 tsp epsom salts.

that really didnt turn too much around for me tho...

According to this book (Grow Great Marijuana), yellowing of new growth is usually either a sulphur deficiency (which is pretty rare) or bleaching from lights being too close.

ah, my man emails.

well right now they are just CFLs on them. so not a ton of heat. id say the lights are about 4" above the plants. so dont know if that could be it?

early on, these guys were in my soil room and the lights were pretty close. they were moved about a week after seed tho into the aero. so they have been acclimated for a bit now.

any advice on how to treat the S deficiency? or what causes it?

Provided you are using decent quality nutes per manufacturers directions, most deficiencies are caused by pH problems (nutrients require a certain pH in order to be absorbed).

So I think skunkushybrid is right on the money (as usual) when it was suggested to make sure your pH is correct.

well thats where i am not sure.

Advanced Nutrients is who makes the nutes i am using. I was goign to go with FoxFarm like most users here with the aero- but the local hydro shop said they used to carry FF but now prefer the AN line of products.


The recommended strength is 5ml/gal. Which is what i am using now. I started at 1/4 stength.

They are on a 16/8 cycle and my pH has been pretty soild at 5.8-6.0

Thanks email... if only that were true. lol

I've actually seen this happen in an aero garden before... I think you need to get an air stone in the res'... aerate the feed.

There is a definite lack of oxygen/nutes to the roots. You can tell it's deficiency by the downward turn of the leaves and the obvious discolouration. They also look overwatered by the limp branches, and general look of the plant.

How does the aero' work exactly? Does it have a deep res'? if it has a deep res', then i suggest getting an air stone in there and filling the res' to an inch below the bottom of the net pots.

This will help oxygenate the feed into the roots.

I would consider upping the nutes - check to see which nute has the sulphur in it.

they don't look nute burned to me - they do look nute deficient (as skunkushybrid mentioned).

I know i saw some yellowing on my plant and i thought oh no! nute burn (it was drilled in my head that the over-nuting is source of most problems). But i since learned my plants love the nutes! they suck down a couple of gallons of nuted water every day. They seem to love it but you'll have to adjust according to how your plants respond.

I personally would go at least 1/2 strength (i would probably go nearly full-strength) to see what happens. your doing hydro, right? you should see results (good or bad) quickly and can flush if necessary.

You may even want to try bringing your pH down to 5.5 - i know that is low but at this point - what can it hurt?

ohhhh - didn't know this was an aerogarden thought this was an aero-hydro set-up. Not sure if that makes a difference but i have no experience with the aerogarden so you may want to disregard what i recommended. sorry about that.

ill give that a go.

im with email tho, you do give some quality advice and raise some intriguing questions.


the res is not very deep on it. id say maybe 6" in the middle. its almost a half circle so the sides are shallower.

really hard to explain how the aero works, because the "pots" arent really pots. they are conical hoppers with a foam cylinder (which acts as the medium to an extent). The hoppers are right above the max fill line, but there is a stream of water that is pumped into each hole in the surface. its like a little waterfall flowing into each seed cup.

so theoretically, the air should circulate enough thru the pumping system to get more o2. but a mass production machine like this is never as it seems.

i could probably find an airstone that fits in there tonight.

like i said, ill post some pics on here later this afternoon.

i appreciate your help, both of you are credible sources in my book.

That's a good point with the advanced nutrients, they have a lot of other additives you are meant to use with their range. So the base nutes come in lower than usual...

The only way to have real piece of mind with your feeding schedule is to get a digital, ec/ppm meter.

emails

im at full strength right now. i didnt think it was nute burn, which is why i upped it from the 1/4 which i was using before.

i was really cautious when i moved them from soil to the aero, and didnt want to overwhelm them with nutes. but its been weeks now, so i upped it to full about 10 days ago.


lowering the ph , eh? what do you think skunkushy?

ok , ive been debating getting a ec/ppm meter.

i have a TDS meter, i used to work for a water purification company.

it measures in ppm, but i personally think those things are shotty anyway.

my ppm for my entire nute solution is about 500. thats pretty low isnt it?

skunkushybrid said:

That's a good point with the advanced nutrients, they have a lot of other additives you are meant to use with their range. So the base nutes come in lower than usual...

The only way to have real piece of mind with your feeding schedule is to get a digital, ec/ppm meter.

Click to expand...

amen to that! i bit the bullet and picked up one of these:HANNA instruments® :: Portable Meters

and LOVE IT!!!

Easy to clean, calibrate and use. And the electrode is replaceable.

did you get it from a site or a store ?

Yeah, lowering the ph may help... also your ppm's seem fine for this stage of growth... although you could do with coming in higher. 560 ppm is fine for a 3 week vegger.

I still think it's an oxygen problem. Like you said, the idea is meant to keep the feed oxygenated, but i don't think it does the job adequately.

Roots are fine, ph is fine, ec is fine... temp of your res'? Temp of the plant environment?

If these are fine also it can only be the oxygen.