Nutrient burn with Mega Crop one part ?

[Chuckeye]

I think it is either calcium or phosphorus, in that order.

Calcium has that shotgun pattern, and isn't progressive in moving up the plant where older leaves are more effected than leaves on the node above them.

It could be lockout or deficiency. Do you know the pH and EC/PPM of the plant, and run-off from the plant? It could be that the more landrace sativa plants are taking up less of the nutrients and it's building in the medium.

Thank you !

All of the girls were getting 6.5g/gallon of Mega Crop @ a ppm of ~900. The Malawi and Apple Betty are fine with it except the Malawi is showing a slight canoeing.

I did a 3X flush on the Wild Thailand and cut off the tips of the leaves.

Three days later there was no progression.

Three days later it was back, sigh....

I don't have the option of customizing the Mega Crop ratios, their suggestion is always to up the feed !
Already at the high end of their schedule...

It was suggested it could also be a nitrogen excess and the Malawi is a dark green.

So I am trying a switch from Mega Crop (9-6-17) to General Hydroponics MaxiBloom (5-15-14) at a ppm of 860.

At next mix I will check and adjust the ph. None of the strains I've grown before needed this but perhaps these two girls are more sensitive to ph....

Or at almost 100 days in the ProMix HP buffering is wearing thin



Cheers

 

[TanzanianMagic]

Thank you !

All of the girls were getting 6.5g/gallon of Mega Crop @ a ppm of ~900. The Malawi and Apple Betty are fine with it except the Malawi is showing a slight canoeing.

I did a 3X flush on the Wild Thailand and cut off the tips of the leaves.

Three days later there was no progression.

Three days later it was back, sigh....

How about a second flush? A lot of nutrients can get dried into the medium.

I don't have the option of customizing the Mega Crop ratios, their suggestion is always to up the feed !
Already at the high end of their schedule...

It was suggested it could also be a nitrogen excess and the Malawi is a dark green.

So I am trying a switch from Mega Crop (9-6-17) to General Hydroponics MaxiBloom (5-15-14) at a ppm of 860.

9-6-17 has a very high K level, which may end up locking out nutrients. 5-15-14 is better.

According to Mulders Chart, high K locks out: Calcium, Phosphate, Nitrogen and Magnesium.

Source: https://www.canr.msu.edu/news/more_reasons_for_soil_testing

Also, different strains may not be using the same nutrients at the same time, so nutrients can build up in the medium.

At next mix I will check and adjust the ph. None of the strains I've grown before needed this but perhaps these two girls are more sensitive to ph....

Or at almost 100 days in the ProMix HP buffering is wearing thin

That's why I always include 1 tablespoon per gallon of magnesium lime. I have hard water of an EC of 0.5 out of the tap. With 0.2 EC or less, I would use 2 tablespoons.

 

[Chuckeye]

How about a second flush? A lot of nutrients can get dried into the medium.


9-6-17 has a very high K level, which may end up locking out nutrients. 5-15-14 is better.

According to Mulders Chart, high K locks out: Calcium, Phosphate, Nitrogen and Magnesium.


Source: https://www.canr.msu.edu/news/more_reasons_for_soil_testing

Also, different strains may not be using the same nutrients at the same time, so nutrients can build up in the medium.



That's why I always include 1 tablespoon per gallon of magnesium lime. I have hard water of an EC of 0.5 out of the tap. With 0.2 EC or less, I would use 2 tablespoons.

Not sure a second flush is going to be any more effective. The time from the run through of the first gallon to the end of the drain of the second gallon of water is close to a half hour. So the medium has been saturated for half an hour. Then the third gallon with nutrients is added.

A little less than 24 hours and the girls are already looking perkier !

Cheers