Yellowing in Coco

[Spinfisher99]

Hi guys,I'm playing around with plants in Coco after a 20 odd year break.When I was growing there was no internet,only a handful of grow shops etc.Any way,I'm loving the new tech,can't believe I can sit on my sofa and control the groom!I'm having a problem with severely yellowed leaves on some Thai basil cuttings and chillie seedlings.(a dry run to get tent setup.)I can't figure out if it's cos my led's are to powerful or if it's nutes.The Thai basil is in 60/40 Coco and clay pebbles.The chillie seedlings are in root riots.I'm watering with formulex and Nitrozyme(750-1000 ppm and 5.8 PH).Also supplementing seaweed and Epsom salts.The lights are Mars Hydro SP 150(seedlings under this fixture show no yellowing) and a Grow Light Science Grow 300(Hi Red Spectrum) which is over the yellowing plants(mother,clone and seedlings.) There are around 100 chillie seedlings,with only 3-4 showing extreme yellowing.I have turned the 300w fixture right down to min. setting.It's hung about 18" above plants.Any ideas would be greatly appreciated.Cheers guys.(I will post photo's when I suss how to do it!).

[Slippy One]

So many variables. What's your water like, have you had it tested? Why you need to add epsom? Try raising or dimming the lights as a process of elimination. My experience is LED are very intense and can damage leaves, tone them down if you suspect them. Another thing with LED is the lack of infrared heat like traditional hps bulbs, so up the heat on your inkbirds to fill the LED void. For me a toned down light and 28C is the sweet spot for plant health. Extra 2 degrees warms the leaves up nicely, heat is something LED lack.

 

[Spinfisher99]

Thanks,food for thought.Your suggestion that temps could be an issue I agree with.I knocked a couple of weak plants out and thought how cold and wet they were.I'm learning that led's need to be used with caution.I have a pareter coming from China.I foliated with Epsom in desperation.My water is hard and around 400ppm.I do use Cal mag,but proba ly need RO.

 

[Spinfisher99]

[stu sleeper 20vt]

I would go with your gut mate.

Throwing everything you have in the cupboard at them only confuses things imo.

Formulex on its own is everything that is needed food wise.

I would advise bottom heat if you do t have it.

But...

Everything is pointing to too much light or wrong spectrum for veg from the 300- from what you say.

Good luck

 

Edited February 6, 2022 by stu sleeper 20vt

[Slippy One]

I’m hard water with a cal mag ratio of 19:1 so adding calmag won’t help that imbalance. Should be 3:1 so I add mono mg, same as Epsom salts. Also, I had more success with hard water specific nutrients, like growers Ark coco range. 

[Guest]

I've got basil under 100w of led in my bathroom and it fucking loves it.  Probably sitting about 24c with the sun and light combined. 

Soft herbs will thrive under 40-80w of led without much fuss.  If you up light levels above that things need to be spot on. 

[Spinfisher99]

Thanks for your input.There are a lot of variables in play.Also first time with Coco and LED. All good expience.Yes I have been guilty of throwing everything but kitchen sink at the grow.My gut feeling is needs bottom heat(just added 2nd heat Matt )and take care not to muller them with too much light.

[Spinfisher99]

UPDATE: Ok,so finally realised it's leaf bleaching due to too much LED power.The light level looked fine to my untrained eye,but I'm guessing maybe it's hard to gauge LED light levels by eye?Can anyone confirm this?I've raised the fixture to around 30",and it's dimmed way down.Plants are slowly re-greening.Happy days,lesson learnt.

 

[Spinfisher99]

UPDATE: Ok,so finally realised it's leaf bleaching due to too much LED power.The light level looked fine to my untrained eye,but I'm guessing maybe it's hard to gauge LED light levels by eye?Can anyone confirm this?I've raised the fixture to around 30",and it's dimmed way down.Plants are slowly re-greening.Happy days,lesson learnt.

 

[Spinfisher99]

UPDATE: Ok,so finally realised it's leaf bleaching due to too much LED power.The light level looked fine to my untrained eye,but I'm guessing maybe it's hard to gauge LED light levels by eye?Can anyone confirm this?I've raised the fixture to around 30",and it's dimmed way down.Plants are slowly re-greening.Happy days,lesson learnt.

 

[Spinfisher99]

Also,as Slippy One explained LED's result in lower leaf temps.So I'm going to switch extraction from high in tent,to low in the tent.Counter intuitive if your coming from HID's,but makes total sense with LED's.Thanks again for all the help guy's.