[Arid_gardener] Citrus in Pots

[Dick]

Your daignosis sounds to this amateur, Diane, like several things could be wrong here.

First, 24 inch sounds quite small for citrus, Even dwarfs. 

The most common problem is the concentration of salts by evaporation from frequent shallow irrigation in pots with inadequate drain holes. Salt will build up to toxic levels. The water table will flow through the root zone until it reaches an equalibrium where attraction to soil particles is equal to the pull of gravity. Below that point, soil is apt to be saturated. Roots cannot live without air so they die from rot.

Frequent irrigation without flushing the previous salt deposit out of the root zone allows evaporation following each irrigation to add a little more salt to the root zone. The only thing you can do is flush the salts out of the soil. What I have done is this;

Be sure there are adequate drain holes in the pots. Find a spot where you can nestle the bottom in soil. Let a water hose trickle at a pace to maintain a quarter to a half inch of water in the pot for at least four hours-all night perhaps to flush out excess salts.

Many pots will channel along the pot walls and they bget wider and bigger from erosion. Pots with this condition may be bone dry except for a narrow fringe around the outside. Take a slat or blunt object and tamp the soil tightly around the perimeter and pack new soil in the cavities you have created.

After flushing a couple times, mix a teaspoon of Ammomium Nitrate in a gallon jug of water and fill the top of the pot and let it soak through.

Your pots could be channelling so that the water flows down along the wall leaving the interior bone dry. That is a common problem in pot culture I have found.

The only fertilizer I have used in my garden is 21-0-0, Ammonium Sulfate, and that appears to be fully adequate in this desert soil that lacks organic material. The sulfur helps too in our alkaline desert soil.

I always add double or tripple drain holes in pots larger than one gallon and, if at all possible, I bury the bottom half inch or so in soil so that the soil in the pot has a direct connection with the soil beneath it allowing the water table to gravitate all the way through the pot pulling fresh air in behind it.

If you suffocate half the root mass by illiminating all the air space in the pot, you are committing murder by strangulation.

This works for me. How do the rest of you handle the problem?

Dick Gross, Master Gardener Volunteer
University of Arizona Maricopa  County
Cooperative Extension.

BCC: Valley of the Sun Gardeners; azcrfg

----- Original Message ----- 
  From: diane elliott 
  To: Arid_gardener at CALS.arizona.edu 
  Sent: Thursday, December 27, 2007 2:24 PM
  Subject: [Arid_gardener] Citrus in Pots


  I have a dwarf tangerine and a dwarf Meyer Lemon in 24 inch pots.

  They both were decimated by frost last year, despite being covered, but came back-but with no fruit.  The tangerine looks fine, nice glossy green leaves, and seems to have recovered well. 

  The lemon tree looks a bit sick-with leaves yellowing at the edges.  They are flood watered when necessary (a couple of times a week, less now).  Is this just end of year leaf drop?  I did give them ammonium sulphate, but someone said it may need 'trace elements'? What would provide this, and when should I do it now it's winter? 


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