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Practice regular soil sterilization. 
CHRYSANTHEMUMS by Avex Laurie 
Continued 
dition of the soil. Steam sterilization may be done 
with 3-inch tile, downspouting with holes punched 
every six inches, or with 1¥2-inch pipe laid in sec- 
tions. This equipment may either be buried in the 
soil or else laid on top, especially in shallow benches. 
A covering of canvas, building paper, or any im- 
pervious material is essential in either case to pre- 
vent the steam from escaping into the air instead of 
penetrating the soil. Concrete benches should have 
the sides covered as well to avoid cracking from 
uneven expansion. At 30 pounds pressure, approxi- 
mately one hour is required to bring the temperature 
of the soil to the necessary height of 160-180° F., pro- 
vided that not more than 50 feet is sterilized in one 
direction. By placing a split header in the center 
of a 100-foot bench and sending the steam 50 feet in 
both directions, 100 feet may be done at a time. After 
the desired temperature has been obtained (use a 
thermometer), the covering may be left on for another 
30 minutes and then removed. 
Steam soil sterilization eliminates most soil pests 
such as nematodes, symphilids, worms, sow bugs, 
etc. It is to be preferred to changing soil both from 
the standpoint of control of pests and diseases and 
the actual betterment of growth. In addition it saves 
labor. 
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FERTILIZERS 
Having applied the superphosphate and calcium if 
needed, either in the form of lime, if soil is acid, or 
gypsum if slightly acid or neutral, the balance of 
nutrients in the soil may be maintained by soil tests. 
Usually, however, two or three applications of a 
complete fertilizer (4-12-4) will be adequate, made 
after the plants are established in the bench and 
until color shows. All commercial fertilizers should 
be used at recommended rates (4-12-4 at 4 lbs. to 100 
sq. ft.) and applied when the soil is moist. 
Excesses 
Too much nitrogen causes poor growth and devel- 
opment of bright yellow leaves at the top of the plant. 
The nitrogen can only be removed from the soil by 
leaching and several heavy waterings may be neces- 
sary for this purpose. Incorporating chopped straw 
into the soil will reduce the nitrates, by the action of 
micro-organisms decomposing the straw. 
Excess phosphorus is rarely encountered. Too 
much potash burns the roots and is evidenced by 
browned leaf margins. Excessive calcium or lime 
causes the soil to become alkaline, and some of the 
elements become unavailable. To counteract alka- 
linity use sulphur at the rate of 2 lbs. to 100 sq. ft., 
or iron sulphate at half that rate. (Fig.1.) 
Deficiencies 
Lack of nitrogen causes the tops of the plants to 
lose their dark green appearance and the lower 
leaves to turn yellow, then brown, and cling to the 
plant. Lack of phosphorus causes the stems of the 
leaves (petioles) to turn purplish and in severe cases 
the veins of the leaf turn purple. Deficiency of potas- 
sium causes marginal browning of the lower leaves. 
This deficiency is similar in appearance to the burn 
from nicotine sprays or fumigations and confusion 
of the two is common. Either muriate or sulphate of 
potash at 1 pound per 100 sq. ft. corrects potash 
deficiency. 
MULCHES 
To maintain uniform moisture in the soil and in- 
crease growth, once the plants are established, a 
mulch may well be used. Peats are best, but manure, 
alfalfa hay, tobacco stems, spent brewers hops, may 
be used. In case of fresh, strawy manure or alfalfa 
an application of ammonium sulphate (1 lb. to 100 
sq. ft.) should be made at the time of mulching or 
soon after to avoid check in growth due to the initial 
withdrawal of nutrients from the soil as the mulches 
decompose. This is not necessary when peat, to- 
bacco or hops are used, because of their slow rate 
of decay. 

