Brown Spots forming on leaf tips?

[thisisfun661]

Issue popped up about 2 days ago
Tents been getting hot - like 80-82 F
VPD still 1.1-1.2
Lights MH SP3000 @30” 22K Lux
Plants growing well, looks good except for this
N.Lights Fem from seed - week 8 veg
Coco & perlite - GH nutes
1150 EC 6.0 ph 1x daily

I did a flush with florakleen a week ago and gradually worked back up to EC because runoff EC was getting pretty high - I think this is because I only feed 1x daily and need to go to 2x? Runoff pH has been 7.1 since flush (6.6 before) and runoff EC has been 300-500.

Any help is appreciated.

 

[Trash_2002]

Could be the start of a calcium deficiency.
8 weeks veg from seed, in coco maybe they could use a bit more than 1150ec uS/cm, something like ec 1250-1500uS/cm.

Do you have a more geral photo of them? So we can see the whole plants too.

Cheers

 

[Trash_2002]

Also don't go too crazy about runoff readings, there's a right way to collect run off so the readings are somewhat accurate, collecting the run off from the plates for example would give you falsely high numbers on EC and much probably false low pH too, read your plants on how they are looking rater than by runoff.

 

[thisisfun661]

Could be the start of a calcium deficiency.
8 weeks veg from seed, in coco maybe they could use a bit more than 1150ec uS/cm, something like ec 1250-1500uS/cm.

Do you have a more geral photo of them? So we can see the whole plants too.

Cheers

Thanks for the reply!

I’m doing 5ml/gal CalMag in each Bach of nutes and all in its finishing at ~1300, so I’m not diluting that too much? But it makes sense what you say because this started after the flush so maybe I un-buffered my coco? If that’s a thing?

I’m feeding 1pt 2x daily now so maybe I can sub one of those with CalMag water and see if it starts to clear up. I get about 1/2pt runoff each time, so like 50%

Plant was a lot more bunched up before but I’ve been trying to mainline this plant - I’ve been training it out and down while defoliating the lowest nodes and cutting bud sites. Once I get all the colas to the ring and each can turn upwards, I’ll stop that and probably flip to flower and let it do it’s thing (I think I’m doing this mostly right?)

 

[thisisfun661]

Also don't go too crazy about runoff readings, there's a right way to collect run off so the readings are somewhat accurate, collecting the run off from the plates for example would give you falsely high numbers on EC and much probably false low pH too, read your plants on how they are looking rater than by runoff.

This is good advice - I just thought it was weird that I was seeing the opposite:

Feeding 1100 EC and runoff @400 EC
Feeding 5.9 pH and runoff 7.2 pH

I do pull from the trays (I hand water) but I swap the plant to a clean tray each time and then water, let the runoff collect for 5-10 mins, and then pour into a clean cup/bucket and EC and pH. Is there a better way?

Thanks again for your insight - this is my first grow, so the input from others has helped me learn a lot.

 

[Trash_2002]

Yep they are hungry, light shade of green overall,
Up your base to EC 1350-1500uS/cm before the cal/mg, pH'ed to 6 as you were already doing

 

[Trash_2002]

This is good advice - I just thought it was weird that I was seeing the opposite:

Feeding 1100 EC and runoff @400 EC
Feeding 5.9 pH and runoff 7.2 pH

I do pull from the trays (I hand water) but I swap the plant to a clean tray each time and then water, let the runoff collect for 5-10 mins, and then pour into a clean cup/bucket and EC and pH. Is there a better way?

Thanks again for your insight - this is my first grow, so the input from others has helped me learn a lot.

Nah I just think it's something you should do ONLY if you have problems, but to be fair it isn't necessary practice at all, checking run offs can often be misleading and inaccurate.
Don't overthinking it can be good for learning to read the plant itself.

The best way would be direct soil sensors (Hanna has some good affordable ones) but they have to be calibrated monthly and the soil pH direct tester sometimes need refilling the electrolytic gel too.

Much better to chase a perfect environment with great genetics than anything else imho, but if you feel the need to check run off as a routine the way is with good soil sensor's.

It's advanced and really only really useful nfor crop steering techniques.

 

[thisisfun661]

Yep they are hungry, light shade of green overall,
Up your base to EC 1350-1500uS/cm before the cal/mg, pH'ed to 6 as you were already doing

To make sure I understand - before I do a CalMag only feeding, just increase overall nute feeding to 1300-1500? I use this recipe so I’m not sure exactly what to increase?

 

[Trash_2002]

Do you use all the products in the chart or only the grow/micro/bloom+ calmag?

 

[thisisfun661]

Do you use all the products in the chart or the trio + calmag?

I’m using everything in the “Late Veg - Day 21 to the flip” formula on the left-center of the chart (w/5 ml of cal mag)

(Except the SM-90 - I use powdered yucca as a wetting agent. AND the H2O2 is for reservoir feeding, so I don’t use that either)

 

[Trash_2002]

That chart for coco seems a bit light handed. Even for everyday fertigation.
Coco has a Low CEC compared to peat for example.

Your base nutrition is the grow/micro/bloom those are the complete nutrition. I would raise that base 20-25% the rest continue applying as is in the chart. Total ec 1500-1750uS/cm

For total EC
Veg week 1 (clones/seedling) ec500uS
Veg week 2 ec750us
Veg week 3 ec1000us
Veg week 4 ec1250us
Veg weeks 4 to 8 ec1250us to ec1750us
Flower weeks 1-3 ec 1750-2000us
Flower weeks 4-7 ec2000us +/- depending on genetics needs.
Flower week 8 ec1000us
Flower week 9 FLUSH TO 250us run of.
Chop.
This is for a 9 week flowering time
Cheers.

 

[Trash_2002]

Now there's the total ppfd per stage too

For total ppfd @ canopy (light intensity)
Use photone Android app calibrated for your light ppfd chart

Veg week 1 250ppfd
Veg week 2 300ppfd
Veg week 3 350ppfd
Veg week 4 400ppfd
Veg weeks 4 to 8 400-600ppfd (increase 50ppfd/week)
Flower weeks 1-3 600-900ppd (increase 100ppfd/week)
Flower weeks 4-8 850-900ppfd stable
Flower week 9 FLUSH and 650ppfd until
Chop.(this lowering in light near the end is optional you could push 900ppfd to the end)

 

[Trash_2002]

Btw those numbers I use for peat/perlite 50/50 media.
But I water 2x per week only as peat can hold and exchange much more nutrients.
It should work pretty well for coco daily irrigation too.

 

[Trash_2002]

To make sure I understand - before I do a CalMag only feeding, just increase overall nute feeding to 1300-1500? I use this recipe so I’m not sure exactly what to increase?
View attachment 1986401

Also this chart you posted is more suitable for crop steering technique with 5+ microdosing irrigation events per day, the numbers I passed for 1x per day are better for your style of coco grow (hand watering 1x per day). The numbers I passed are more in line with GH medium feed chart a lil bit customized.

 

[thisisfun661]

Wow! Awesome advice! CFC does advocate “high frequency fertigation” that’s automatic, 5x a day on a reservoir and pump. I haven’t really committed to that yet, but how you explained it makes a lot of things make perfect sense; since germ the two plants I’m running have seemed to grow slowly and have always been light green and/or had light green streaks.

Also, thank you for the direction on the light. I’ve wondered if this was why they were moving slow and now i can double check against this.

Really appreciate the knowledge and assist!

 

[Trash_2002]

All good mate happy to be of any help.
For veg, i veg 10 plants in a 1.2m2 tent with 260w LED (four 65w quantum boards without dimmer)
I had some problems with light intensity with led in the start (was used to MH bulbs),but made an adjustment, my veg lights don't move they are fixed almost to the top of the tent in a distance that when I transplant the clones they get exactly 250ppfd and they grow towards the lights at full intensity, so the ppfd raise to 550 naturally when they are ready to transplant to flower. They seem to love this approach.
I'm soon to move to leds to flower since my country banned all incandescent light, no more hps replacement to be found.
I will use the exact same approach even when my LED flowering bar light have dimmer, set em high enough at full power so the ppfd is exactly 550-600ppfd when I transplant them there, let them slowly grow towards the light until by week 4 flowering they reach my target ppfd of 900 (no CO2)
From there I can adjust the height/dimmer of the bars if needed. To maintain the 900ppfd from flower week 3-4 to the end of flower.

 

[Trash_2002]

Thanks for the reply!

I’m doing 5ml/gal CalMag in each Bach of nutes and all in its finishing at ~1300, so I’m not diluting that too much? But it makes sense what you say because this started after the flush so maybe I un-buffered my coco? If that’s a thing?

I’m feeding 1pt 2x daily now so maybe I can sub one of those with CalMag water and see if it starts to clear up. I get about 1/2pt runoff each time, so like 50%

Plant was a lot more bunched up before but I’ve been trying to mainline this plant - I’ve been training it out and down while defoliating the lowest nodes and cutting bud sites. Once I get all the colas to the ring and each can turn upwards, I’ll stop that and probably flip to flower and let it do it’s thing (I think I’m doing this mostly right?)
View attachment 1986396
View attachment 1986397

Yes, feed them drain to waste (30% run off is good) to keep salts from acumulating. And drain to waste really don't let the runoff on their plates, trow it away or on your house garden.
Never water coco with water only, it messes things up, always with nutrients.
Your training is pretty good, and plants are looking good too. Follow the feeding and ppfd strengths I posted they will thrive ;-)
If you feel they need more or less food always adjust strength with your base nutrients (grow/micro/bloom) proportionally.