Help? high PPMs in runoff, too much nutrients?

WintersBones

WintersBones

Well-Known Member
Im a newb with nutrients and coco. my four plants are about 11 days since sprouting and a few days in their final pots. All autoflowers in a coco mix medium. Worried I've overfed them or they're not getting enough Nitrogen perhaps? Until now I've been giving them a light watering of seedling strength GH 3 part + CalMag every day and a half or so, but i just checked the runoff and its showing between 1250-1450PPM~2690-3160us/cm and pH 7.3, which seems really high. Have i overloaded the nutrients in my coco mix and at risk of lock out? Medium is coco coir with some wormcast/organic compost mixed in and lots of perlite. Ive given it a flush with just CalMag and lowered pH'd water out of caution. The plants seems okay but a couple are maybe a little light colored, and a couple with purplish stem/stalks. I think the pH is an issue, so I'll be watching that closer now. Was this the right choice, backing off on the nutrients and giving a heavy flush like this? Or have I just over watered them now and should just wait for them to dry out and go back to a ligher nutrient solution? TIA
 

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xtsho

xtsho

Well-Known Member
You do NOT have to water small seedlings everyday when growing in coco. If you keep the coco too wet before the plants develop decent roots they will sit there drowning in the soaking wet coco. Let those dry out not completely but damp and then feed them only 1/4 strength or less nutes.
 
WintersBones

WintersBones

Well-Known Member
Ya, its getting the balance of wet/dry and how long to wait before watering again that I'm trying to figure out now. Coco is definitely a different beast than the soil I'm more used to. Im just worried that letting it dry out too much will spike the salt levels as my runoff PPMs are still so high. I'll definitely be backing off on the nutrients a bit until that looks better. I also suspect i may have had my lights too close and some of the light/washed out coloring im seeing might have been early signs of light burn, so I've raised the lights a few inches. This morning they were perking up again and not looking any worse I think, so I think I'm going in the right direction.
 
Pook

Pook

Member
Hey Brother! Your PPM is a little high, try to get your PPM to 1150. The pH should be somewhere around 5.8-6.2 (might be where the purple stems are coming from). What is the pH of your source water and water run off?

-Pook
 
xtsho

xtsho

Well-Known Member
WintersBones said:
Ya, its getting the balance of wet/dry and how long to wait before watering again that I'm trying to figure out now. Coco is definitely a different beast than the soil I'm more used to. Im just worried that letting it dry out too much will spike the salt levels as my runoff PPMs are still so high. I'll definitely be backing off on the nutrients a bit until that looks better. I also suspect i may have had my lights too close and some of the light/washed out coloring im seeing might have been early signs of light burn, so I've raised the lights a few inches. This morning they were perking up again and not looking any worse I think, so I think I'm going in the right direction.
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You don't need to go any higher than 400 ppm at this point.
 
WintersBones

WintersBones

Well-Known Member
Ya pH is likely part of my problems. I wasn't watching it as closely as i should have at first. Im now lowering my input water to around 5-5.5 for the last few waterings. Runoff still coming out above 7pH however.
 
xtsho

xtsho

Well-Known Member
WintersBones said:
Ya pH is likely part of my problems. I wasn't watching it as closely as i should have at first. Im now lowering my input water to around 5-5.5 for the last few waterings. Runoff still coming out above 7pH however.
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Just set the pH to 6. Don't chase runoff pH by trying to adjust it by what goes in. Feed a steady pH and everything will balance out. You don't want to dump too low of a pH based on what the runoff pH is. I've been growing in coco for years and have never once checked runoff pH. I just make sure what goes in is the right PPM's and pH. If you do that then everything is groovy at the roots.
 
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