Help needed with Avocado tree health

[dds88]

Hey everyone, I'm new to the site but what an awesome site it seems to be! I have become very interested in Arborism and bought the ISA text book, I've always loved botany! Anyway I digress.

I have a 3 year old avocado tree (germinated a pit from a store bought avocado) and it's done great in my apartment for the two prior season cycles. I unfortunately have been having trouble with the health of the leaves.



They are browning on the tips and over time they brown into the center of the leaf. A whole leaf that has gone through this process ends up falling off but the patterns it make are quite wave like.

I read online that this could be a deficiency of Phosporus and/or Potassium so I got a different NPK ratio fertilizer and hoped that would work. I even crushed oatmeal and egg shells in a mortar and pestle and fed that to the soil.

What has me worried is that because it's spring and all the tree is sprouting new limbs and it looks great but over the past couple days I've noticed that the brand new leaves are now following suit to what was happening before.

I love this tree and I don't want it to die.

Is it an infestation?
Do these trees/pits, because they come from a grocery store, often just die off before they reach maturity?
Does fertilization need to be a lot higher because this is a living tree now.

 

[BC WetCoast]

I was interested in your post because you were in a place where you grow avocados. Then I noticed you were in Toronto

 

[dds88]

I was interested in your post because you were in a place where you grow avocados. Then I noticed you were in Toronto

Haha yea it's a bit chilly. But it's done fine, great in fact before for the last two winters

 

[Oldman47]

If you are sure the plant is getting enough water, try checking for moisture before adding any water. Until the soil feels bone dry on your finger, it doesn't need water.