Tropical Fruit > Tropical Fruit Discussion
Urea Foliar Spray to Address Nitrogen Deficiency in Container-grown Avocado
z_willus_d:
I have three several year old Avocado trees growing in large food-grade barrels cut three-quarters up. Leaves on the trees almost always (regardless of season) look a pale unsightly color that ranges from brown (dying) to yellow to lime-yellow-green. The pics here what the plants look like at their best, which ain't that good. I've contemplated reasons for the leaf heath, considering the containers and root-binding, relatively cool temperatures in the winter season (though these are cool-hardy Mexican varieties), damping and/or root-rot in the container, and finally nutrient deficiency.
I was thinking about hitting the trees with several, sequential foliar sprays of low biuret urea (similar to what folks use on citrus). This is done in the industry apparently. But as I was researching this idea, I came across the following articles, which seem to suggest there is limited benefit to Urea foliar applications on Avocados. The fruit production was nearly halved (vs. control) in one of the varieties as well.
I'm curious if others on this forum have contemplated this question? Also, what do folks recommend to give a deficient tree a heavy blast of N to green-up the leaves. Assuming, you agree that N-deficiency is in play here with these three trees.
Thanks!
http://www.avocadosource.com/arac/sum_1990/sum_1990_pg_15-16.pdf
http://www.avocadosource.com/Journals/FSHSP/FSHSP_VOL_110_PG_136-138_1997.pdf
z_willus_d:
Oh, I wanted to note that one of the pictures clearly shows the die-off from cold damage on the flowers of a Fuerte tree (the middle tree). Many of the flowers survived, but about half did not. This picture was taken a month or so back.
Cookie Monster:
why not just give it some slow release osmocote with minors.
z_willus_d:
As for the Osmocote, that's exactly what I've been using. The plus bags from Amazon. I've read that a Avocado tree requires literally pounds of N in a year, so perhaps that slow release Osmocote isn't enough. Also, it requires heat and some moisture to work, and it's been relatively cool and watering has been via rain vectors lately. I'm thinking I need a one-time N-infusion on these trees.
spaugh:
Your trees look pretty good to me but I am on a cell phone again. They look pretty maxed out size wise for their containers. Fuerte for sure is not going to be super happy in a pot. They really want to grow huge. What are the other types?
For fertilizer, instead of giving urea, try using a balanced fertilizer made for avocado and citrus. Soil drench or foliar with disolved urea will surely give them a boost but thats not a good long term solution. You are better off getting some grow power 8 6 8 or similar avocado food and get the trees on a regular feeding schedule with that. It will work better than the osmocote if you are diligent and feed every month or 2 a small amount during the hot season. Your trees are not large enough to need a ton of fertilizer but because they are in pots they will want regular feeding. Based on your recent posts and all the work you have been doing, regular feeding should not be a big deal for you.
For my in ground trees (and potted baby trees) I go out every few months and pitch a few handfulls of gro power onto the mulch and water it in. Its pretty painless and I have good results.
Navigation
[0] Message Index
[#] Next page
Go to full version