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Quick 1

Noticed some a fair bit of yellowing on 1 of the leaves on 2 plants in early veg at the min and looking for quick advice as to what deficiency/excess you guys think it is.


Week 2 veg

Coco / perlite 

Canna A + B 25ml per 10L

Rhiztonic 10ml per 10L

Cannazym 25ml per 10L



The only 2 leaves that have this on the 3 plants.


Cheers guys

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Might need to go through and check the entire environment etc :) 



Autos or photoperiod?



What temp is your heatmat set to? And where is the probe?



What's the Relative Humidity and temperature of the growing space both during lights on and off?



Do you know what the feed strength is in EC? As your tap water will affect the feed strength.



What pH is the feed?



Is this your first coco grow?









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They're photoperiod,  heatmats set to 22.5c and the probes inserted into the coco. RH is normally around 50% but checked this morning and it was 45%. 


Just checked the app and the temp at lights off is around 19c but has been increasing at about 3:30am due to the heating coming on til lights on (oops). RH at lights off is around 55%


The feed is 5.8 pretty much every time as for EC I don't normally check it I probably should but I'm following a feeding schedule from canna so didn't really feel the need to check it. Altho I do have a meter incase. 


Tap water round here is very hard last time I checked it was 470ppm out the tap lol but am leaving it 24 hours for chlorine to evap


This is my 4th coco grow I only started in March last year so all help and advice welcome 


Cheers :D

Edited by le0n.v6

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Been growing for years but still a relative newbie in coco :D


Definitely get the EC meter out :)

feeding schedules/guides don't know your plant/environment or how hard your water is ;)



You probably realise that the low lights off temp is probably not helping,

might not be the cause but definitely not helping. 



Those pots look pretty big, 

when did they go into these? 


Have you checked your water suppliers website to see if they say how much Calcium and Magnesium it contains? 






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Cal mag is a problem with coco supposedly it leaches… thus meaning it’s a good idea to add extra if your using some already and just using it in general if you wasn’t planning on using it. 

Sure someone will clear it up ;)

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If your water is really 470ppm, you need to deionize with resin or use reverse osmosis. Dilute your tap water 50/50 with treated water to make it usable. Check your water suppliers website for total solids to give you an idea if the reading is accurate. 300ppm-ish is the limit really. Too many dissolved solids gets progressively harder for the plants to uptake it as they increase.Your top limit for dissolved solids is basically around 600pm... for a noob anyway to be safe. With your water apparently being 470ppm, that does not give you much room to add nutes before you are in lockout territory. Nutrient makers recommended levels are generally OTT. Sort the tap water ppms first and confirm the reading. You may find, once you've sorted that you have an overdose problem with the nutes because they are being uptaken correctly, but Canna's recommended levels may be too high. Trust your ec/meter when you know it's ok and work with 600ppm/1.2ec as your max level, until you feel confident enough to experiment with higher levels.

Edited by catweazle1

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