ahh, crap. pH lockout, nute burn...you tell me.

OK, so I've tried figuring out this problem for a few days and I've yet to see any kind of change for the better, and I am at a loss of what to do. I was at first thinking calcium or magnesium deficiency, but it was happening to all my plants (even small ones) and I'm watering with tap water, so I started figuring it was pH lockout. Let me get some pics up.


It basically starts at the tips of the leaves, then I start noticing rough patches. Before long, the tips are necrotic and the spots turn to the rust colored thing.

At first my leaves were just turning shiny and curling. I started a lot of these plants out on nutes even when they were small, but I figured nute burn would start at the new growth, and all my new growth seems fine.

I had them planted in a humus/perlite mix and thought maybe the humus didn't have everything it needed so I got a bag of fox farms. Switched to the fox farms and wasn't seeing anything get any better, so I made a mix of 25% miracle gro soil, 25% ffof, 50% perlite, and a pinch of dolomite lime and transferred some to there.

Tell me what you think, I'm gonna get some better, newer photos.

It looks identical to another post that I saw that someone had, and his seemed to be nute burn. However, he laid off his nutes and his were fine. I've not only laid off the nutes, but have taken the potency of my soil down and still don't seem to be noticing any difference.

Also, I checked the pH of my tap water, and it was really high- like 7.5, maybe even 8. I pH'd my water down to like 5.5 and 6 last night and watered.

Hah, aaaand of course. I think I know what my problem is.....

After spending days and days researching what is going on, I make a post and then 5 minutes later I think I've come across my answer....

I think that my phosphorus has been locked out, not from pH but from cold temps. I found this picture and it looks identical to my seedlings, not to mention I had like 10 seeds that didn't germinate, they turned to mush. I'm pretty sure that happened BC it was too cold.


I'm gonna go throw some clothes on and try and find a heating pad to stick under my tray.

Are you using fertilizer already?

Yeah, I started doing a lot of experiments, and almost all of my plants got nutes. But even a couple of the ones that were never fed are showing the problem.

I have 1 plant that's about 8 inches tall, he's been getting nutes for a while, and actually hasn't been fed in about ten days, maybe more and the problem is still getting worse. I'm really thinking that my cold night temps and nighttime waterings have caused a phosphorus lockout. I had some seeds that I germinated and then put in soil, that didn't grow at all. Some of them just turned to mush and popped like zits when I squeezed them. That coupled with the fact that I've had very little growth and its happening to all my plants has led me to think I could use a heating mat..

Ok, sounds good then.

ThorGanjason said:

Yeah, I started doing a lot of experiments,...
...
bla...
bla...
bla...

Click to expand...

And you wonder why your plants looked bad and have weird leaves, looked burned, and etc...

Sand4x105 said:

And you wonder why your plants looked bad and have weird leaves, looked burned, and etc...

Click to expand...

Haha, everybody's giving me so much hell for trying to learn. Look, I have 40 plants (mostly seedlings) growing and I only have space for 4. I have 4 plants that are my controls, and even they are getting sick, so my experiments aren't causing the problem.

I mean how does everyone else around here learn, by just sitting and waiting until something screws up? I must be a fucking lunatic for trying to have control of when and how my plants mess up the first time around.

The man that doesn't make mistakes is the man not doing anything to quote H.E.Willis.

your soil might be to hot

Sounds like you need one of these...http://www.kindgreenbuds.com/cannabis-grow-bible.html. Never feed this young, your soil has more than enough food to sustain a plant twice this size. Buy a ppm and a tds meters and start recording what and when. A ph of 5.5 is to low for even hydro. Do some reading and if they get worse try again. Ever think it might be the strain?? You said that only a couple popped?

yeah good soil can take up to 4 weeks or so before it needs anything other than water. and use dolomite lime in the soil and you dont have to worry about your PH in your water so much.

unless your grow room was like 30 degrees i dont think its from being too cold.

Temps near 50 or even 55 will show up in the leaf color. The cold locks out P and you see more purple in the leaf. But it doesn't get necrotic and die like you describe. You started feeding too early. I thought I saw fading of intervein area of pic 3. That's Mg. You described rust colored spots. That's Ca. put some dolo lime in your soil mix from now on. For now, a lime drench will give you Mg and Ca. Epsom Salts gives you Mg also and the plant absorbs it faster Mg from dolo lime. Hope that helps

Thanks a lot guys, and yeah I actually picked up 40 pounds of dolomite lime the other day, BC I was thinking it was cal/mag deficiency too.

I'm sure that my feeding them so early has a lot to do with it, but like I said even the ones that haven't gotten any nutes are starting to do it (although they were the last ones to get it, and still the most healthy.

BTW, I checked the pH of my tap water, and the color was green leaning towards blue, so I figures it was around 7.5 going in. Should I pH the water?

Also, I've been thinking my soil was too hot also (its just weird, they are a bunch of different ages, but the problem started hitting them all at the same time regardless of age, and different soil types, etc..)

BTW, I wanted to re-emphasize that the main reason I'm pretty sure the phosphorous is locked out by the cold soil is BC of what happened to my seeds. They germinated overnight, and I put them in soil and waited a week. I wound up digging them up after nothing popped up, and they had barely grown at all (if any), and the seeds basically turned to mush. I can't imagine anything other than the cold that could do that.

Sir.Ganga said:

Sounds like you need one of these...http://www.kindgreenbuds.com/cannabis-grow-bible.html. Never feed this young, your soil has more than enough food to sustain a plant twice this size. Buy a ppm and a tds meters and start recording what and when. A ph of 5.5 is to low for even hydro. Do some reading and if they get worse try again. Ever think it might be the strain?? You said that only a couple popped?

Click to expand...

Thanks for the link, yeah I knew feeding this young would be detrimental for them, but I just wanted to see what nute burn looked like. I def plan on getting a ppm and TDs meter here in a couple weeks when I have the money.

About the strain I actually have several different strains going, only 3 plants are good strains and the other ones are bag seed.

I have been getting purple in the stems (the stem of the leafs, mainly) and I thought it was a characteristic of the strain, but now I'm reading that also can be a sign of phosphorus deficiency/lockout.

ThorGanjason said:

BTW, I wanted to re-emphasize that the main reason I'm pretty sure the phosphorous is locked out by the cold soil is BC of what happened to my seeds. They germinated overnight, and I put them in soil and waited a week. I wound up digging them up after nothing popped up, and they had barely grown at all (if any), and the seeds basically turned to mush. I can't imagine anything other than the cold that could do that.

Click to expand...

Why dont you sprout your seeds inside then? Lettem grow a couple inches and put them outside?

ThorGanjason said:

Thanks for the link, yeah I knew feeding this young would be detrimental for them, but I just wanted to see what nute burn looked like. I def plan on getting a ppm and TDs meter here in a couple weeks when I have the money.

About the strain I actually have several different strains going, only 3 plants are good strains and the other ones are bag seed.

I have been getting purple in the stems (the stem of the leafs, mainly) and I thought it was a characteristic of the strain, but now I'm reading that also can be a sign of phosphorus deficiency/lockout.

Click to expand...

Its better to see what nute burn looks like in flower than when theyre four inches tall. You my friend are not going to learn from anything but trial and error impo

Edit: double post