What are these brown spots?

[Cheffrey]

I give cal mag to the plant. Other plants are doing fine.

Humidity has been low entire grow. It's at its highest now averaging 30%

Could it be boron deficiency?

 

[Emilya Green]

I am thinking calcium... this plant is just more needy than the rest... Its not bad though, and if you increase the calmag just a bit you will probably keep it from getting worse.

 

[Cheffrey]

Ok, my next watering isnt for a couple days, best to wait till then for calmag increase?

 

[Emilya Green]

yes, it is not a crisis worthy of messing up a watering cycle. Just remember next time you grow this strain that it has extra needs and try to prevent this problem early.

 

[Cheffrey]

Ok, I have 2 of this plant... this one has always given me grief tho. Other one of the same is doing great

 

[Cheffrey]

@Emilya
More brown and other plant of same strain showing same deficiency... calcium you think still? I fed more cal mag, doubled it 2 days ago.

 

[Emilya Green]

yes, looks like more of the same. Since she is not responding as well as you think she should with the added calmag, let's review pH... mag is most mobile toward the lower end of the scale. Also, 2 days is barely the blink of an eye to a plant... let's wait a couple of watering cycles before we are sure about the response. For now, continue on... try not to freak while we wait. Keep in mind too that this damage will not reverse, it will simply stop progressing once you have licked it.

 

[Cheffrey]

So ph around 6? Ideal? I've been feeding 6.5 to 7

 

[Emilya Green]

6.3 is ideal...
Most soil drifts upwards because of the buffers built into the medium. If you come in at 6.5 to 7, and it is heading upwards from there, you don't have much time at all before you get out of the 6.2-6.8 useable range in soil... and any elements most mobile at the lower end of the scale, never have a chance. Magnesium is one of those.
Also, there is a huge difference in acidity between each tenth of a point of pH. Accuracy does matter.

 

[Cheffrey]

Ok great, I think I may need a new ph pen