Help with Amnesia Haze auto please!

[Tal420]

Hi, I've been following this forum for a while but it's my first time posting.

I'm currently growing an Amnesia Haze auto, it's been vegging for 35 days now and looks like it's just about to start flowering.

Temp in grow tent is 24 deg C, and relative humidity is 57%.

I am growing in Biobizz Lightmix soil, 25% perlite, 5% vermiculite under Mars Hydro FC E6500. I'm measuring around 580 umols using Photone.

For nutrients I am using organic BioGrow, also by Biobizz. I am giving the recommended dose, i.e. 2ml per litre.

Starting from last week I noticed that the new growth on top of the plant has some yellow tips. Initially I thought it was light burn and increased the light height up to 40cm. However the issue still remained and soon after I started noticing small brown dots/patches on some of the lower large fan leaves. These have increased in the last few days, so now I am suspecting it's calcium deficiency or nutrient burn.

Today I measured the pH of the aquarium water I use for feeding. It reads 7.2 which I know is a tad higher than desired.
pH in soil is roughly the same, in the range of 7 to 7.5.

I must add that I am also growing an OG Kush in the exact same soil mix, using the exact nutrients and same pH. The OG Kush is not showing any of these symptoms.

My dilemma is whether I should first lower the pH from the next feed, or whether I should go straight to use Cal Mag.

I'm attaching a few pictures showing the top nodes with yellow tips, and some pics of the worst fan leaves from the lower part.

Any help would be greatly appreciated

Thanks!

PS: is it too early to start feeding her BioBloom?

 

[HappyHazmat88]

Hey sorry for your troubles can I ask about your watering schedule? Main plant your asking about is showing all the signs...brown spots...droopy leaves...yellowing new growth..etc of over watering....and it's a VERY common issue.

Also the other plant seems to nitrogen deficient has downward claw with yellowing and start of wilt?

Have you considered starting a journal....you'll receive broader help.

 

[Tal420]

Hey sorry for your troubles can I ask about your watering schedule? Main plant your asking about is showing all the signs...brown spots...droopy leaves...yellowing new growth..etc of over watering....and it's a VERY common issue.

Also the other plant seems to nitrogen deficient has downward claw with yellowing and start of wilt?

Have you considered starting a journal....you'll receive broader help.

Thanks for your prompt reply

I was just about to edit my post to say I'm watering around 2L every 3 to 4 days. The pots are 19L. I read somewhere that overwatering may look like calcium deficiency.

What would you recommend I do, hold back from watering a bit?

Re the OG, well spotted yes it has claws and the colour is slightly yellowish however it was always that colour from the very beginning. Is there a way to address Nitrogen deficiency? I guess going above the recommended dose for BioGrow is not recommended.

For what it's worth, both plants do not seem stunted, eg the Amnesia grew 3cm in 2 days.

Many thanks once agian.

 

[VetSmoke85]

I'd also adjust the pH of your feed to 6.3. The soil will buffer it up through the range and the nutrients will be more available. That along with a good wet/dry cycle and you should be golden. With autos you can start introducing bloom a little earlier (when they start to flower) so I'd say you could start adding a small amount.

Oh and lift the pots to feel how light they are. Don't water again until they're really dry. The pots will feel really light.

 

[HappyHazmat88]

Thanks for your prompt reply

I was just about to edit my post to say I'm watering around 2L every 3 to 4 days. The pots are 19L. I read somewhere that overwatering may look like calcium deficiency.

What would you recommend I do, hold back from watering a bit?

Re the OG, well spotted yes it has claws and the colour is slightly yellowish however it was always that colour from the very beginning. Is there a way to address Nitrogen deficiency? I guess going above the recommended dose for BioGrow is not recommended.

For what it's worth, both plants do not seem stunted, eg the Amnesia grew 3cm in 2 days.

Many thanks once agian.

Hey yea no problem that's what ya came here for lol and just because holding off on water is the simplest least stressing option try there first ..... So for a natural nitrogen additive you could use a top dress like blood meal and coffee grounds (be careful of the grounds as they could raise pH )

You got this no worries, some color issues but they look to have dense growth so your right not stunted.

 

[HappyHazmat88]

Oh and lift the pots to feel how light they are. Don't water again until they're really dry. The pots will feel really light.

This is good advice as far as I'm concerned I use the same method plus actually weighing them.

 

[Tal420]

Thanks all for the good advice. I will be more careful with the wet/dry cycle and will lower the pH to 6.3.

Should I forget about CalMag for the time being? I've grown photos for a number of years using same nutrients and technique and never had to use CalMag. This is the first time I encountered this issue.

 

[HappyHazmat88]

I do not use cal-mag personally...so I cannot weigh in on it. But sounds like you have a plan. Let us know how it turns out.

 

[Tal420]

Yes I will lower pH in the next couple of feeds and see how it goes. Hopefully it wont get worse in the meantime, it will be a few more days until I can water again.

 

[bluter]

you should use the calmag. the plant is starting to pull for flower. it'll be a bit shy on phos and pottassium. time to get ahead of the nute sched.

 

[Tal420]

you should use the calmag. the plant is starting to pull for flower. it'll be a bit shy on phos and pottassium. time to get ahead of the nute sched.

Thanks @bluter .

Since there is a slight chance that my issue is caused by higher pH or overwatering, if I follow the recommended dosage for CalMag, is there a risk of burning it further? Or is it safe to start adding it anyway?

I know some growers use it all the time unconditionally, in my case I always thought that with good soil and relatively hard water, calcium is never short in supply.

For watering I use water from my 400ltr malawi chiclid tank with no chemical filters. For the aquarium I use tap water (dechlorinated).

 

[bluter]

Since there is a slight chance that my issue is caused by higher pH or overwatering, if I follow the recommended dosage for CalMag, is there a risk of burning it further? Or is it safe to start adding it anyway?

little to no risk with clamag. start with 1/2 dose and watch

I know some growers use it all the time unconditionally, in my case I always thought that with good soil and relatively hard water, calcium is never short in supply.

there are other factors. some plants need more. led will pull piles of it out and require supplementing.

For watering I use water from my 400ltr malawi chiclid tank with no chemical filters. For the aquarium I use tap water (dechlorinated).

never heard of it. no idea the level of filtering you get. best results are almost always with RO. if your tap is lower ppm you can use that. never use water that you don't have a ppm for,

 

[Tal420]

I didn't realise LED lights will pull out more Calcium.

That may explain why this is the first time I'm having these issues. All my other grows before this were under HPS, this is the first time I'm growing under LED.

Re water I can check the ppm. What value should I be aiming for?

 

[bluter]

Re water I can check the ppm. What value should I be aiming for?

anything sub 120 ppm will give you control if you are feeding the plants yourself. if you are using the water as a feed then i can't advise. a lot of folk use aqua culture - feeding with nutrient rich aquarium water.

 

[Tal420]

anything sub 120 ppm will give you control if you are feeding the plants yourself. if you are using the water as a feed then i can't advise. a lot of folk use aqua culture - feeding with nutrient rich aquarium water.

I use the aquarium water and add organic nutrients as well.

After you mentioned ppm, I checked the ppm of the aquarium water BEFORE adding nutrients, and it was 1900 I still have to test ppm after adding nutrients but I'm assuming its gonna be over the roof

Tap water measured 1700ppm and bottled water 0ppm.

Could this be the root of my problem? And if its the case, will watering with soft water + normal feed fix the issue?

 

[Phytoplankton]

I use the aquarium water and add organic nutrients as well.

After you mentioned ppm, I checked the ppm of the aquarium water BEFORE adding nutrients, and it was 1900 I still have to test ppm after adding nutrients but I'm assuming its gonna be over the roof

Tap water measured 1700ppm and bottled water 0ppm.

Could this be the root of my problem? And if its the case, will watering with soft water + normal feed fix the issue?

Yes, that could be the issue. Use the bottled water. I have extreme hard water like yours and I have issues with lockout.

 

[Tal420]

Thanks, for the next feed I will reduce ppm of the base water, and pH down to 6.3. That should improve nutrient absorbtion, then see how it goes

 

[Tbe]

I used the same foundations as you on last grow,
Biobizz light mix + starter pack
6.3 for water
Light 20/4
And heat from 22 to 27
Replace air in tent I think upto 12 time per hour is good enough
Lift your pots for water weight before watering.
I think you can use biobizz one watering then plain water the next

After that let me go

 

[Tal420]

By way of an update, I fed her twice since Sat, making sure that pH is 6.3 and ppm around 900. I fed her the full dose, BioGrow, BioBloom and Topmax.

It seems to have improved but today I noticed a couple of new small rust spots, so I guess its not completely over yet.

This is how its looking now. I may give CalMag a shot with the next feed?

 

[bluter]

you're looking gold. you could up the nutes just a touch to between 1000 - 1100 ppm. you don't even have nute tipping, so it could use a general bump, but it's gonna ask for more p and k going forward from this point.