Seedling Yellowing Problem

[Leebone]

I've got 5 seedlings in a little home made grow box and they are almost three weeks old.
Today i noticed a few of them had lower leaves yellowing..
4 days ago they were given general nutes and got a bit of burn so yesterday i gave just water and now today yellow leaves so I'm pretty sure i can rule out nitrogen deficiency but have no clue why one leaf looks almost moldy..
The other photo the leaf at the bottom middle dosnt look yellow in the pic for some reason but can be seen to be lighter than the rest.

 

[Major CBD]

I'll just walk you through my thought process. I wouldn't use white cups. I've seen success with solo cups but they are colorful blocking out light. Your soil looks like organic/mulch potting soil... Decomposing wood chips equals higher ph. Nutrition at week 3 is understandable but these guys are still so small I wouldn't hit me with nutrients until they looked like they were at week three. If you wanted to go to flower at week three you could if you wanted a smaller plant. She looks like week one after gem. Wondering what kind of light and environment you got for this little guy. Is it a "window grow"?

 

[Mr Bee]

As already mentioned your medium looks a bit dodgey.probably soil for acid loving plants thats not ideal for weed.
u need good soil with good drainage and an airy texture.canna soils are ideal for a new grower.

 

[Seamaiden]

In my opinion that soil isn't really soil, and is probably still decomposing. That will cause all kinds of problems. If you can, get a good quality potting mix and use that. It should *not* have obvious pieces of wood in it.

Don't feed right now, that can make things worse.

 

[Leebone]

I'll just walk you through my thought process. I wouldn't use white cups. I've seen success with solo cups but they are colorful blocking out light. Your soil looks like organic/mulch potting soil... Decomposing wood chips equals higher ph. Nutrition at week 3 is understandable but these guys are still so small I wouldn't hit me with nutrients until they looked like they were at week three. If you wanted to go to flower at week three you could if you wanted a smaller plant. She looks like week one after gem. Wondering what kind of light and environment you got for this little guy. Is it a "window grow"?

Yeah mate you hit it all on the head..trying to do things on the cheap.
Soil is crap but its so hard to find good stuff in the hardware stores here in Australia. Its all just mulchy potting mix so i normally bit a bit of blood and bone with it but i didnt on this to see what would happen and the results arnt good so far.
They are inside a grow box and i have four 135w 5500k cfls the big ones.
I've also got them on 24 hrs this time as well and I'm thinking the lack of sleep is making them small? What's your thoughts on that?
I've grown plants in there before with great success in the vegging stage..have changed the soil to a finer mulch for the seedlings this time but its always been cheap soil with not to many problems..

 

[Leebone]

In my opinion that soil isn't really soil, and is probably still decomposing. That will cause all kinds of problems. If you can, get a good quality potting mix and use that. It should *not* have obvious pieces of wood in it.

Don't feed right now, that can make things worse.

The soil is very poor..its hard to find good stuff here without buying it on the net..do you recommend any other than the canna stuff..cant get prices on their website.

 

[Seamaiden]

If you're in Australia I'd have to talk to some people about what's available down there first. If you can find Gardener & Bloom Blue Ribbon potting soil, that stuff is fantastic and a fair price.

 

[Leebone]

If you're in Australia I'd have to talk to some people about what's available down there first. If you can find Gardener & Bloom Blue Ribbon potting soil, that stuff is fantastic and a fair price.

Thanks
I got ahold of some canna terra found a dealer here for $30 a bag so I'll give that a go and hopefully fixes the problem..
Thanks for your help

 

[Leebone]

Ok so i changed to terra soil..removed all the old soil from the roots so i just had roots with a green top. Transplanted into terra and and amazingly no shock and came back really well for a week.
I cut the yellow leaves off so i could see if it was still happening..
They continued to grow another 3 or 4 nodes and were looking healthy but now have gone back to square one again with the leaves yellowing from the bottom up..
The soil wasn't the problem something else must be the issue.
These are new bulbs im using and i thought i got a steal on them for $10 each off ebay..they are photography cfls and are 135w and 5500k seems fine to me with four of them should be just enough watts for 5 plants..is there anything wrong with this..?
I was thinking they could be dud seeds but all 5 have the same problem and one hasnt had any growth in a couple of weeks..
Water out of my tap is sitting at a 7ph so shouldn't be high enough to kill the plants and like I've said i have grown a few plants now but never had this problem.
I also installed a cooling system into my grow box this time around so i can close the door and not have to leave it a jar let heat out..i would have thought that would have only improved it..
I'm really lost on this one...

 

[Nog]

I'm thinking the soil is not aerated enough.

Also get some real lights, CFL's are not for growing weed.

If in Australia, start your seeds in Osmocote professional seed raising and cutting mix, and mix in a small amount of perlite with it.

Store bought potting mixes work well, doesn't matter if they have some bark in them, that helps aerate them.

But they do vary a lot in composition, the one's from your supermarket are usually not much good.

There is a brand called Hortico which was good, haven't seen it around for a while now, and also another cheap one is Bloom, which is ok.

I tend to look around and make sure no-one is looking and then poke a hole in the bag of potting mix to see what it's like.

Also I mix some lime in with the potting mix, as potting mixe's go a bit acidic as they break down.

Check Nog's "The Big Black Widown Grow Out" thread on the Mr Nice forum on this site for an example of how plants can grow in commercial potting mixes mixed with perlite and a bit of lime.

But as for your plants, I think not enough soil aeration leading to lack of oxygen to the roots, and also a bit of overwatering.

Anyway don't mess around with CFL lights, they are not for growing weed.
Get yourself a 400 W MH at the least.
They shouldn't be very expensive.

The most important thing is the light, don't skimp on that.
You can skimp on everything else, fans, nutes etc, but spend all your money on the light.

 

[Leebone]

I'm thinking the soil is not aerated enough.

Also get some real lights, CFL's are not for growing weed.

If in Australia, start your seeds in Osmocote professional seed raising and cutting mix, and mix in a small amount of perlite with it.

Store bought potting mixes work well, doesn't matter if they have some bark in them, that helps aerate them.

But they do vary a lot in composition, the one's from your supermarket are usually not much good.

There is a brand called Hortico which was good, haven't seen it around for a while now, and also another cheap one is Bloom, which is ok.

I tend to look around and make sure no-one is looking and then poke a hole in the bag of potting mix to see what it's like.

Also I mix some lime in with the potting mix, as potting mixe's go a bit acidic as they break down.

Check Nog's "The Big Black Widown Grow Out" thread on the Mr Nice forum on this site for an example of how plants can grow in commercial potting mixes mixed with perlite and a bit of lime.

But as for your plants, I think not enough soil aeration leading to lack of oxygen to the roots, and also a bit of overwatering.

Anyway don't mess around with CFL lights, they are not for growing weed.
Get yourself a 400 W MH at the least.
They shouldn't be very expensive.

The most important thing is the light, don't skimp on that.
You can skimp on everything else, fans, nutes etc, but spend all your money on the light.

Some good points mate but still don't see why they are slowly dying.
I had shitting potting mix had same problem..now i have good soil (terra) which people on here have recommended..it can't be the soil it is airy and light as and I'm only watering every three days.. when i first started growing i used to drown them in water and never had a problem..I've done alot of dumb things and and been cheaping out on everything the whole way and have had plants yield up to 3 ozs and never had problems like this..
Do you think my cooling system with an exhaurst fan as an intake and another as an outake would not be letting enough oxygen into the box?
This problem has only started since i put that in and closed the door..

 

[BudBogart]

Some good points mate but still don't see why they are slowly dying.
I had shitting potting mix had same problem..now i have good soil (terra) which people on here have recommended..it can't be the soil it is airy and light as and I'm only watering every three days.. when i first started growing i used to drown them in water and never had a problem..I've done alot of dumb things and and been cheaping out on everything the whole way and have had plants yield up to 3 ozs and never had problems like this..
Do you think my cooling system with an exhaurst fan as an intake and another as an outake would not be letting enough oxygen into the box?
This problem has only started since i put that in and closed the door..

That looks like very typical nitrogen shortage. Have you fed them?

 

[Leebone]

That looks like very typical nitrogen shortage. Have you fed them?

Yes they have plenty of nitrogen for a small plant and the soil has a ratio of about 12▪14▪24
Nutes that i use have all the essentials so it can't be a deficiency of anything.. from my experience it takes a bit longer than 4 weeks to start yellowing with no N.

 

[Seamaiden]

What about soil and water pH parameters? Perhaps a lockout is occurring.

 

[Leebone]

What about soil and water pH parameters? Perhaps a lockout is occurring.

My water is at 7 and my soil before i add water is 6 so its pretty good and definitely not going to kill the plant like it is.
They are literally dying at a very fast rate. I've started germing more because i give them 4 days and they will be tossed in a garden bed..
It must be something to do with my grow box that is making this happen.
One strain is going very pale almost whole thing yellow..other strain is yellowing then browning to crispy and burning the shit out of the top leaves.

 

[Leebone]

Hello, this plant food and liquid bloom for hydroponics or soil are available on eBay for anyone in the U.S., this is good for people that are tired of paying high prices for inferior products, you can also save 10% by purchasing directly from me.
View attachment 618025

Thanks but my nutes are fine been using same stuff for a while now..
All you need is water and light and oxygen to grow a plant it can be done on the cheapest way as long as you provide those three things a plant will grow.
Its something to do with my set up it has to be..I've grown in this box before with good results

 

[Nog]

My water is at 7 and my soil before i add water is 6 so its pretty good and definitely not going to kill the plant like it is.
They are literally dying at a very fast rate. I've started germing more because i give them 4 days and they will be tossed in a garden bed..
It must be something to do with my grow box that is making this happen.
One strain is going very pale almost whole thing yellow..other strain is yellowing then browning to crispy and burning the shit out of the top leaves.

Actually sounds a bit like fungus gnats, the yellowing of the leaves that then turn brown.

Have you seen any little black flies coming out of the top of the soil when watering?

 

[Leebone]

Actually sounds a bit like fungus gnats, the yellowing of the leaves that then turn brown.

Have you seen any little black flies coming out of the top of the soil when watering?

No its not gnats..I've had them before and never had yellowing or burning with them

 

[Leebone]

Why is it so hard to get an answer from "professional" growers.

 

[BudBogart]

Why is it so hard to get an answer from "professional" growers.

You have determined it must be light, water, or oxygen related. It must have something to do with your grow box.
With those parameters no one has been able to offer suggestions that you consider. You are looking for a professional to agree it must be your grow box. If it's grow box related you will need to describe your grow box, lighting and cooling, ventilation, etc. it's frustrating when things go south. Hang in there.