to grow glads successfully here. In contrast to rain water, which is neutral (pH7), our 
city water is pH 7.78. This makes our problem more difficult. In November 1947 I 
divided my largest two glad beds into sections for test purposes. One-third of each bed 
received no acidifying material, but agricultural sulphur was worked into the remainder 
at the rate of four pounds to 100 square feet. The foliage of the plants grown in the 
untreated plots in 1948 was very chlorotic and several contained so little chlorophyll 
that they died prematurely. In a few instances the foliage was a bright cream color 
with faint green veins. The leaves on the other plants were yellowish green to light 
green. The plants that did bloom made spikes that were hardly worth cutting. As a 
result of the excess calcium in the soil the manganese, iron, and possibly other ele- 
ments required by the plant for the formation of the chlorophyll (the green coloring 
matter) and for normal growth, combined with the calcium to form insoluble com- 
pounds in the soil and thus were not available to the plants. The important element, 
phosphorus, likewise is said to become “fixed” at pH values above pH7'4. This de- 
ficiency condition does not occur when the pH value of the soil is between 534 and 7. 
The optimum soil reaction for gladiolus is probably. about pH6. The foliage of the 
plants grown in the treated plots was a medium green and I am convinced that. twice 
as much sulphur would have given better results under my conditions. This fall I shall 
treat all plots accordingly, as approximately five months are required to reduce the 
soil reaction to the acid side. 
Incidentally, I had incorporated liberal amounts of cow manure in my soil and, 
contrary to general belief, this tends to increase the alkalinity. Bone meal also has an 
alkaline reaction, but ammonium sulphate, cotton seed meal and potassium sulphate 
(sulphate of potash) all produce an acid reaction. Practically all of the imported peat 
mosses, and many of the domestic brands, should reduce the pH of the soil satisfactor- 
ily if a three inch application is dug in several months previous to planting. It also 
has the added advantage of supplying a desirable form of organic matter. 
Together with gardeners in other states that have mild winters, we learn that one 
of our worst pests is the root knot nematode. It attacks the roots of several hundred 
species of plants, including gladiolus. It punctures the roots and mutilates them to 
such an extent that they are unable to function properly. These affected plants are 
stunted, light in color and wilt readily. This soil organism is so tiny that it can hardly 
be seen without the aid of a microscope, under which it has the shape of a miniature 
eel and appears to be almost transparent. Knot-like growths form on the infected 
fibrous roots and, in addition, the primary roots are abnormally thickened. Although 
there are several control preparations available for use in the small garden, nearly all of 
them are rather expensive and disagreeable to use. One recently produced by a promi- 
nent oil company, and another by a leading chemical firm, appear to me to be very 
effective and reasonably priced. Large areas of cultivated land in southern California 
are being treated with these materials by commercial operators. 
Our most common native tree is the mesquite. They are not confined to the 
desert and canyons, but are also found on many residential lots. Two of my glad beds 
are within 10 feet of half-grown mesquites. Their fine fibrous roots penetrate the 
beds a few inches below the surface and rob the plants of the much-needed moisture 
and plant food. The only solution of this problem for me is to kill the trees. 
However, despite all the handicaps of nature, I have seen many beautiful spikes 
produced here. I shall continue to plant the queen of flowers and strive to improve 
my growing conditions. 
WILLIAM J. EHRINGER, 
Nogales, Arizona. 
