Is this nute burn?

simpleleaf

Well-Known Member
The new growth looks good on all of them. One plant, 2nd photo, looks quite healthy, do you know why?

I grow in potting mix, haven't used clay balls. Can't you just lower the EC of the nutes? Will doing that affect the healthy plant?
 

TheZombywoof

Active Member
They are all on the same res and everything should be equal for all 4 plants... but they are from seed so you never know with phenos.

Right now, I have flushed the res (0.0 ec) and PH'ed to 5.8. If you look close you can see the rust creeping up on the new growth.
 

simpleleaf

Well-Known Member
It seems likely that one plant's genetics tolerates the conditions better than the other three. The new growth on all of them looks good to me. I'd be inclined to try 0.5 EC and observe. My notes on my formula sheet say 0.5 for clones to 0.8 for seedlings.

If I think of anything else I'll write again. Hopefully this conversation will spark interest from others.

Edit: I did think of something else, 5.8 to 6.2 pH is reported as typical for cannabis hydroponics, that's also a variable you can change, but it's best to do one change at a time.

 
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simpleleaf

Well-Known Member
I think the 1.0 EC was slightly high for the size of the plants, based on EC schemes I've seen and scribbled down on my formula sheet.

An indicative EC range for cannabis plants is 0.8-1.3 for seedlings; 0.5-1.3 for clones; 1.3-1.7 under vegetative phase; 1.2-2 during flowering. Different varieties of cannabis might require significantly different values of EC.
You'll note your 1.0 value was not necessarily outside those ranges. Another set of ranges are found in Fluence Engineering's High PPFD Cultivation Guide. In Table 10, for cannabis, they recommend 0.3 to 0.7 for establishment, 1.0 to 2.0 for vegetative, and 1.5 to 2.6 for reproduction.

When I looked at your plants in an earlier thread, I thought the damage looked like calcium deficiency. I just checked them again, and it still looks like a good possibility to me.

I would try changing one thing at a time, and observe any changes over a few days. If your good plant begins to look sick, back off and restore older values.
 
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