Too much or too little nutrition?

[Gregorius Green]

I'm not sure if the plant get too much or too little nutrition. Could also be some pH issue I guess.

I took some pictures to show the status of the plant.

Here's some info:
The strain is Amnesia CBD. It's around 4 weeks in flowering.
I'm growing in a pre fertilized soil. There is lime in the soil so pH is around 7.
I use tap water, pH around 6,5 after a little adjustment.
I have not feeded much nutrition with watering since there should already be plenty in the soil. I tried to add little bit but I cannot say I have seen positive effects from it.
Light is a 400W HPS.

I can see that the tips of many leaves are burnt and curled up which usually is a sign of too much nutrition. But then I also see a lot of pale green/yellow leaves that could be a sign of deficency. So I'm a bit confused really. Any ideas what could be done?

 

[hotrodharley]

Needs phosphorus and potassium. Basically a bloom feed.

 

[CannaCountry]

Could stand some Mg as well...

 

[polishpollack]

Interesting that people can say what a plant needs when the contents of the soil haven't been given nor the additional nutrients. Why don't we see what's in that soil first. What and how much, how long was veg, what addition food has been given, how much each time and how often, before we tell the grower what we think the plant needs.

 

[hotrodharley]

Interesting that people can say what a plant needs when the contents of the soil haven't been given nor the additional nutrients. Why don't we see what's in that soil first. What and how much, how long was veg, what addition food has been given, how much each time and how often, before we tell the grower what we think the plant needs.

Pretty much going by the pics? And his narrative where he says he doesn't feed much? Kind of an educated guess. And the OP has disappeared.

 

[Gregorius Green]

I have some magnesium carbonate already in the soil.

I have some PK-booster I could try to add.

I think it's the burnt leaf tips that confuse me. I thought that was a sign of too much nutrition. Maybe it's not?

 

[hotrodharley]

I have some magnesium carbonate already in the soil.

I have some PK-booster I could try to add.

I think it's the burnt leaf tips that confuse me. I thought that was a sign of too much nutrition. Maybe it's not?

Your newer leaves are normal looking. More than nitrogen excess can cause tips to blanch or die back. Use your PK booster. Also use a skewer or screwdriver or something to pierce the soil through the roots all the way to the bottom for aeration. It will also help water to get to the bottom of the root zone.

 

[Gregorius Green]

Thanks hotrodharley and everyone else for your comments, I'll try some of your suggestions and see how it goes!

 

[polishpollack]

What's in the soil???

 

[polishpollack]

Those pics look more like an over fert than anything else.

 

[Blitz35]

I'm growing in a pre fertilized soil

I use tap water, pH around 6,5 after a little adjustment.
I have not feeded much nutrition with watering since there should already be plenty in the soil.

What exact soil are you growing in? Name of it? A picture of the bag?
What are the ppm's of your tap water? What exactly are you feeding and how much and often?
Distance from your hps light? Your temps/humidity?
Is all that 1 plant in the first pic? Seems the left side is ok, and one section in the middle looks bad..right where the light seems to be. Do you have a fan? which direction does it blow?

 

[polishpollack]

 

[Gregorius Green]

What exact soil are you growing in? Name of it? A picture of the bag?
What are the ppm's of your tap water? What exactly are you feeding and how much and often?
Distance from your hps light? Your temps/humidity?
Is all that 1 plant in the first pic? Seems the left side is ok, and one section in the middle looks bad..right where the light seems to be. Do you have a fan? which direction does it blow?

Look guys I appreciate the effort to help. I added som PK-booster to the water last time I watered, so I'll wait a bit and then update the results.
I don't live in the US so I don't think mentioning the soil name is much help. What I can say is that it is a soil made for plants that thrive on a lot of nutrition. It's made of mostly peat moss and contains chicken manure and organic fertilizer NPK 9-3-4, and dolomite lime.
I don't have a way to measure tap water ppm but I'm pretty sure it's low. The water is very soft, pH slightly above 8. I add a few drops of apple cider vinegar to lower it to around 6.5
I have three plants and I thought this one was a good example to show.

 

[Gregorius Green]

And actually looking back at the pictures and comparing with the plants now, I think they look worse now...
Maybe I'll flush them to get rid of excess nutrition.

 

[Aussieaceae]

What's the drainage in your soil like, and how many times in the week are you watering?

I agree, likely overfed.
Sounds like you had a lot of rich organic matter to start with, and probably didn't need to fertilize.

I'd try to avoid a flush right now though.
Have you a way of checking your soil's ph?
How much pk booster are we talking? PK% as well.
Did you supplement the pk booster, because the above symptoms were showing?

 

[Blitz35]

Look guys I appreciate the effort to help. I added som PK-booster to the water last time I watered, so I'll wait a bit and then update the results.
I don't live in the US so I don't think mentioning the soil name is much help. What I can say is that it is a soil made for plants that thrive on a lot of nutrition. It's made of mostly peat moss and contains chicken manure and organic fertilizer NPK 9-3-4, and dolomite lime.
I don't have a way to measure tap water ppm but I'm pretty sure it's low. The water is very soft, pH slightly above 8. I add a few drops of apple cider vinegar to lower it to around 6.5
I have three plants and I thought this one was a good example to show.

In today's age..the name of a soil can easily be looked up and seen Without really knowing details, it's very hard to offer advice. Not sure why you added a pk booster..the symptoms on the leaves are not showing either a potassium or a phosphorus deficiency, now you're flushing that out. Once you figure out the details and can give proper info, maybe proper help can be given, until then, you may be chasing your tail. So many posts, and still no idea about your environment, what you are feeding, how often you're watering..in any case, best of luck, hope you figure out!

 

[Beachwalker]

I agree with blitz, but without more info a guess would be your pH is off, making your soil acidic, and you're locking out

 

[Blitz35]

I agree with blitz, but without more info a guess would be your pH is off, making your soil acidic, and you're locking out

I was actually thinking the opposite. He mentioned soil ph 'is around 7'...he waters with water 'around 6.5 ph'. Doesn't sound like he's fed alot. If it is ph related, i would say it may be a bit high, as in these peat moss blends, ph of around 6.1-6.3 is what i found works best. When i was going higher at around 6.5-6.7 at the start, i would always run into issues with micros...though the yellowing didn't look like op's. My original guess was heat related, but hard to see in the pics, and op has ignored that part of the question in my last reply..temps/humidity, distance to light? It's a guessing game without more input.

 

[Gregorius Green]

What's the drainage in your soil like, and how many times in the week are you watering?

I agree, likely overfed.
Sounds like you had a lot of rich organic matter to start with, and probably didn't need to fertilize.

I'd try to avoid a flush right now though.
Have you a way of checking your soil's ph?
How much pk booster are we talking? PK% as well.
Did you supplement the pk booster, because the above symptoms were showing?

Drainage is fine. I use fabric pots and there's some perlite in the soil also.
I water two times per week usually.

I have Plant magics Old timer organic PK 2-4-8. I fed 2 ml last time to each plant.
Temperature in grow tent is 28° C, and I have a circulating fan blow just above the plants.
It's 400 W HPS in there in a cooltube. Distance to plants approx 50 cm
Air humidity is low, 25%.

If pH is close to 7 in soil, is that too high? I thought thats what dolomite lime does in the soil, buffer to pH 7.
I know for sure that the soil is not acidic.

 

[Gregorius Green]

Oh yeah, I forgot to mention that I had a spider mite infestation earlier during the grow. I sprayed all the plants with soap water + a little alcohol, three times, one week between each spray. As far as I know they have not come back. Last time I sprayed was two weeks ago. I didn't notice any immidiate damage from the spray.