The Low Down on Dirt
Desert soil generally falls into one of these categories:
rocks, sand, or clay. Or a horrible combination of these.
High pH (alkalinity) is the norm. Oh yes, I almost forgot to
mention high salt content, too. Deep loamy soil with neutral
pH, the kind of nutritious soil, rich in organic material
that gives plants all they need, is simply not found in hot,
So your first step when you are planting a garden should be
to improve the soil. In fact, if you plan to spend $100 on
your garden, the first $80 should go into soil amendments!
Plants grown in soil rich in organic materials are more
likely to remain healthy and resist pests and diseases.
So how do you improve the soil? By
clearing out any rocks, then digging in compost or soil
amendments available at nurseries or home improvement
stores. These organic materials will help bring the
soil--whether it is sand or clay--closer to the neutral pH
and give it that high-nutrient, loamy texture plants love.
You probably will also want to add fertilizer that has been
especially prepared to combat our high pH. Ask about this at
the plant nursery.
And how often should you amend?
Unfortunately, adding organic materials is not a one-time
event. You should do it at least once a year to maintain
plant-friendly dirt. Good soil needs about 5% to 7%
composted organic material.
Be sure that all amendments you add
have been composted. Digging in green leaves or fresh grass
clippings without composting can do more harm than good.
Small rocks in the soil are not a
problem In fact, they will help loosen the dirt and allow
for better drainage. Big rocks, obviously, can block root
Beware: if you have heavy clay soil,
whatever you do, do NOT add sand in an attempt to make it
lighter or drain better. What you will end up with is adobe
brick! Lots of compost, dug into the clay, will make it
lighter and the plants happier.
Now about caliche. Caliche is a
white or ivory-colored calcium carbonate substance that
occurs in cement-like layers throughout our desert. The
layers, which can be from a few inches to many feet thick,
may appear near the surface or deep below. Caliche near the
surface can block root growth causing plants to be stunted
or die. And it takes a pick axe to break through a caliche
If you are planning to put in
a pool it pays to have a soils engineer dig test holes to
see if the site has caliche. Removing caliche to make room
for a pool can be very expensive.