The tips of the leaves on my Mexican Avocado are turning brown (it seems to be moving up the plant). and there is some yellowing too. What do you think? I've found several answers online, but nothing definitive...
I've found this info elsewhere:
"Water thoroughly but do not keep the trees too wet. At every third or fourth irrigation, water extra heavily to help wash accumulated salts from the soil. This will minimize salt burn, which will be noticeable as brown edges develop on the edges and tips of leaves."
"Potassium deficiency is indicated by a burning of older leaves. Unlike salt/fertilizer burn it is limited to older leaves."
"Magnesium deficiency causes older leaves to yellow at the tips and then die back. It can look very similar to salt burn but can be distinguished from salt burn by the fact that it concentrates itself on older leaves and affects the leaf tip rather than traveling the margins of the leaves"
"Salt burn, unlike potassium and magnesium deficiency, is evenly distributed across all leaves of the plant. Salt burned leaves start burning at their tips and progressively turn crispy along the edges of the leaves toward the base."
Sorry one more post, I found this at the Texas A&M page on Avocados:
"The most common problem of avocados in Texas is tip burn and marginal necrosis caused by water stress and salinity, which is most prevalent during hot, dry weather. This problem is most acute on Mexican-race seedlings and rootstocks; it can be tempered somewhat by more uniform and regular watering. "