Solo cup issue

[TangieD]

Hi,
Help needed pls if possible.
The plant is about 20 days old, never been right since transplated into solo cup, it was started in an Aero garden for kicks before moving seedling to solo cup.

temp; 75F
humidity; 66%
PPFD 400
Mother Earth coco/perlite - I believe this is an underlining issue as 4 other seedlings stunted and would not grow either.
nutrients; Plagron cocos a+b 200PPM and ph5.8 balanced.
Used ph meter, tds meter and PPFD app Photon.

I seem to think it’s a magnesium issue but not sure, the coco was at PH7.0 straight out of the bag so flushed etc before potting up. After flushing pots theu were charged with 200PPM nutrients.

 

[Olderfart]

You will likely want to wait for a more experienced commenter, but I think your ppms are a tad low for straight coco/perlite. You may be correct that leaf symptoms indicate Mg deficiency, but I suspect that that is caused by low ppms, not imbalance in your nute mix. For perspective, my current coco girls are now at 1100EC which is likely 550ppm if you are on that conversion scale, and all four plants (3 different strains) are happy. Are you fertigating to significant runoff? If not, that could also be part of the problem. You need to get something like 10-20% of what you put in out the bottom of the cup. If you have not already done so, have a careful look at Cocoforcannabis.com, there is excellent information there directly applicable to your grow.

If others agree, I would up your ppms to 350 immediately, and to 450 a couple days later. Bumping it the full amount in one go may shock the plant by causing too quick a change in osmotic pressure on the roots. Once you get it to 450, keep it there for a week or so to see how the new growth responds and if color could still be darker, you can notch it up ~50ppm at a time. Each time you adjust ppm, leave it for several days to see how new growth responds. If tips yellow or claw, back ppms back down 50ppm until new growth looks happy.

Good luck with it,. I am new at this, so you may want to wait for confirmation from others before doing what I suggest.

 

[TangieD]

You will likely want to wait for a more experienced commenter, but I think your ppms are a tad low for straight coco/perlite. You may be correct that leaf symptoms indicate Mg deficiency, but I suspect that that is caused by low ppms, not imbalance in your nute mix. For perspective, my current coco girls are now at 1100EC which is likely 550ppm if you are on that conversion scale, and all four plants (3 different strains) are happy. Are you fertigating to significant runoff? If not, that could also be part of the problem. You need to get something like 10-20% of what you put in out the bottom of the cup. If you have not already done so, have a careful look at Cocoforcannabis.com, there is excellent information there directly applicable to your grow.

If others agree, I would up your ppms to 350 immediately, and to 450 a couple days later. Bumping it the full amount in one go may shock the plant by causing too quick a change in osmotic pressure on the roots. Once you get it to 450, keep it there for a week or so to see how the new growth responds and if color could still be darker, you can notch it up ~50ppm at a time. Each time you adjust ppm, leave it for several days to see how new growth responds. If tips yellow or claw, back ppms back down 50ppm until new growth looks happy.

Good luck with it,. I am new at this, so you may want to wait for confirmation from others before doing what I suggest.

Thanks for the quick reply and support. I will take onboard what you have said forsure. Will hopefully get a few more comments before I dive in with a fix ✌

 

[Olderfart]

Thanks for the quick reply and support. I will take onboard what you have said forsure. Will hopefully get a few more comments before I dive in with a fix ✌

Someone should get back to you shortly, I am surprised no one has yet.

 

[Mañ'O'Green]

I do not know the precise numbers for the nutrient line that you are running but in Mega Crop 2 part nutrients you do not get a balanced nutrient profile until you mix enough of it. For the MC it is 550 PPM to 600PPM minimum. The balance continues to improve up to about 1000 PPM and then begins a decline. So your plants are starving for the missing or locked out nutrients. By taking your PPM up to 550 you will have a better chance of getting a balanced mix. It is also great if you can mix up a bucket with an airpump so you can make a larger volume. It will keep a week easily.

 

[TangieD]

I do not know the precise numbers for the nutrient line that you are running but in Mega Crop 2 part nutrients you do not get a balanced nutrient profile until you mix enough of it. For the MC it is 550 PPM to 600PPM minimum. The balance continues to improve up to about 1000 PPM and then begins a decline. So your plants are starving for the missing or locked out nutrients. By taking your PPM up to 550 you will have a better chance of getting a balanced mix. It is also great if you can mix up a bucket with an airpump so you can make a larger volume. It will keep a week easily.

Thanks for the info @Mañ'O'Green fantastic help and pointer to possible cause. Going to make up nutrients as per manufacturers spec (EC1.3 on their chart which is 650ppm so will drop it a little to 500-550ppm) and see if that helps

 

[TangieD]

Fed the plant with 575ppm, let’s see if that has an impact thanks again @Mañ'O'Green.