Topics in Subtropics

Mature avocados may be a big tree, but they have very shallow roots. The bulk of them are in the top 8 inches of soil. The tree therefore does not have access to a large volume of stored water. As opposed to a deep rooted walnut, they need frequent, small amounts of water.

The canopy is thinning. The leaves are small and yellow. There is dieback in the canopy, with leafless tips on the branches. You dig around under the canopy in the wetted area of the sprinkler and you can't find roots within 6 inches of the soil surface or if you do find them they are black.

Since the first publication of this article on vole damage in citrus, a recent field observation regarding vole activity is worth noting. Voles prefer a situation where there is cover and shelter generally from weed or grass.

Most growers know the N-P-K numbers on fertilizer, but that doesn't tell you what else might be in the material, either as a contaminant or something purposely added to the material.

After a 30-year career as the farm advisor of subtropical fruit crops in San Diego County, I've decided to retire to do some other things, including some fishing. According to my wife, that seems to mean some painting, re-tiling the floor, re-landscaping and cabinet work.