Cultural Pointers 
SOILS 
Chrysanthemums will grow in a wide range of soil 
types, but a fibrous silt-loam is preferred. Blue grass 
sod, to which rotted manure has been added, plus 
an application of superphosphate will give excellent 
results. The reason for the great care in soil prepara- 
tion is to permit penetration of water and a uniform 
supply of fertilizer. If water remains on the surface of 
your soil for more than a few moments after watering, 
your soil is not of good structure. 
Acidity 
Evidence shows that the soil reaction should be slightly 
acid, pH 6.5, although in many instances a neutral 
medium does very well. If your soil tests slightly 
alkaline, apply one-half to one pound of agricultural 
sulfur per 100 sq. ft. of area. However, if your soil is 
acid, apply 3 to 5 pounds of agricultural ground lime- 
stone per 100 sq. ft. of area. 
Steam Sterilization 
Steam sterilization is the only practical means known 
to destroy the Verticillium wilt organisms present in 
many soils. The cuttings you purchase are free from 
wilt, but if planted in soil that is not steam sterilized, 
many will contract the trouble. 
Old soil, when properly managed, will give results 
comparable to fresh soil. Add a quarter of the volume 
of humus in the form of manure or peat moss. Steam 
sterilize to destroy the Verticillium wilt fungus, as well 
as improve the structure of the soil. Steam sterilization 
may be done with the use of 3-inch tile or down spout- 
ing with one-eighth inch holes drilled every 6 inches on 
each side of the pipe. Use 2 lines in a three and one- 
half foot bench. Ridge the soil to the center of the 
bench directly over the lines, covering with a tarpaulin, 
canvas or Sisalkraft. The Thomas method is very similar, 
with the exception that the pipe is laid on top of the 
rototilled soil and then covered so as to make it air- 
tight. The Thomas method is not recommended where 
purlin posts are in the bench. 
By introducing the steam in the center of a 100-foot 
bench and sending the steam in both directions, a 
more thorough sterilization is accomplished than if the 
steam were to be forced in at the end of the 100-foot 
bench. Cover the sides of the benches so that the 
entire bench and contents are heated to 180 degrees 
Fahrenheit. Remove the covering one hour after the 
steam has been cut. This allows the excess moisture 
to pass from the soil as vapor. We are now recom- 
mending that you plant immediately after the soil has 
cooled. Water in the plants heavily so that you are 
combining watering and leaching into one operation. 
Continue to water heavily every time you water. 
Chemical Sterilization 
A chemical which has proven its worth is Larvacide. 
This material must be used when the greenhouses are 
empty to avoid injury to adjoining crops. This gas is 
applied in liquid form with a special applicator so that 
2 or 3 c.c. are applied at 10-inch centers. The soil 
should be moist before applying. A good suitable 
covering should be placed over the treated soil to keep 
the gas in the soil for at least 48 hours, although a 
water seal applied 2 to 3 times every 24 hours will 
suffice. The soil temperature should be at least 60 
degrees or higher. When used properly you can expect 
favorable control of insects, diseases and weed seeds. 
Dowfume MC 2 has been tried and found to control 
nematodes, weed seeds, and some damping-off or- 
ganisms. Best results are obtained when the soil tem- 
perature is above 60 degrees. About the same 
procedure should be followed in its application as that 
described for Larvacide. 
Supporting Standards with the String Method 
Thomas Method of Steam Sterilization 
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