“Mum,” Culturdel Jusiructions 
By ALEX LAURIE 
Professor of Floriculture, Ohio State University 
SOILS 
A fibrous soil, well aerated by having granular structure 
and adequate amounts of organic matter, is necessary. 
The use of manure or peat at the rate of at least one- 
quarter by volume is desirable. Extremely heavy soils are 
benefited by inclusion of fine cinders (less than 14 inch) 
or even sand together with the organic matter such as 
Michigan Peat. 
Acidity 
Since Chrysanthemums do best in slightly acid soils, 
additions of lime are not recommended except in areas 
where extreme soil acidity exists. However, calcium is 
often low and in that case in slightly acid or neutral soils 
gypsum or calcium sulphate could well be added at the 
rate of 2 lbs. to 100 sq. ft. If available soils are alkaline 
an application of sulphur at the rate of 2 lbs. to 100 square 
feet will be found desirable. Since, however, this material 
is a slow acidifier, it should be added several weeks in 
advance of planting. A pH of 6-6.5 is best. 
Levels of Nutrition 
If soils are tested and they really should be, the follow- 
ing levels in parts per million (do not confuse these with 
pounds per acre) should be maintained: nitrates 10-25, 
phosphorus 5, potassium 20, calcium 150. It is well, how- 
ever, not to have the nitrates high at the time of benching— 
10 p.p.m. is more than adequate then. High nitrates at 
the start check growth and are frequently responsible for 
the yellowing of foliage and stunted appearance. Heavy 
leaching in well drained soil will correct such a condition. 
Usually superphosphate should be added (5 lbs. to 100 
square feet) at the time of soil preparation to insure a 
proper distribution of that material since surface applica- 
tions are ineffective for a long time. For a short time crop, 
such as the Chrysanthemum, slowly acting bonemeal 
could well be eliminated from consideration. 
Steam Sterilization 
In this connection, it may be well to state that there is 
no necessity for the complete removal of soil from benches 
or beds every year. If the old soil is free of disease, its 
rejuvenation may be accomplished by the addition of one- 
fourth of the volume of peat and manure. This addition 
may be made at the rate of two-thirds peat and one-third 
well rotted manure. However, it is absolutely important 
that such soils be sterilized with steam. This serves a dual 
purpose. It destroys the verticillium wilt fungus and at 
the same time betters the structural condition of the soil. 
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. 
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 square feet) and applied when the soil is moist. 
Excesses 
Too much nitrogen causes poor growth and development 
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 necessary for this purpose. Incor- 
porating 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 be- 
come alkaline, and some of the elements become unavail- 
able. To counteract alkalinity use sulphur at the rate of 
2 lbs. to 100 square feet, or iron sulphate at half that rate. 
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 phos- 
phorus causes the stems of the leaves (petioles) to turn 
purplish and in severe cases the veins of the leaf turn 
purple. Deficiency of potassium causes marginal browning 
of the lower leaves. This deficiency is similar in appearance 
to the burn from nicotine sprays or fumigations and con- 
fusion of the two is common. Either muriate or sulphate of 
potash at 1 lb. per 100 square feet corrects potash deficiency. 
MULCHES 
To maintain uniform moisture in the soil and increase 
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 sul- 
phate (1 lb. to 100 square feet) 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, 
60 WE CATER TO WHOLESALE AND RETAIL FLORISTS 
