
Y 
Spring RHA iy) Chrysanthemums 
Chrysanthemums can be produced at any time of year, providing day length, temperature, insects and 
diseases are controlled correctly. Our research workers in various federal and state institutions have 
shown us that chrysanthemums can be flowered the year around. The chrysanthemum has great variety 
of colors and types and also has excellent keeping quality. Both the retailer and consumer are inter- 
ested in this and they will welcome the addition of chrysanthemums the year around. 
Season has been eliminated and the flowering time can be accurately controlled. You can use varieties 
that are best for your market. Some varieties are excellent for the August to November bloom but 
are worthless during the winter and spring months because of the poor light intensity at that time. 
Daylength Control 
It has been known that the days are short enough for bud formation around September |. This will 
vary somewhat depending upon your location in the States. To prevent flower buds from forming 
it is desirable to lengthen the day with additional light starting August 15. When one is using black 
cloth to reduce the length of the day the treatment can be discontinued September !. 
Similarly in the spring the days are too long for further bud formation starting April 15. To prevent 
bud formation light the plants until April 20. If you want bud formation start shading March 15, or a 
little earlier if you are in the extreme southern states. 
Black Cloth 
If you are using black cloth during the period from March 15 to July 25 be sure to have opaque 
cloth so that very little light passes through the cloth. Cloth that has been previously used very 
likely will not be dark enough, so make tests with a light meter before using. Heavy’ canvas dyed a 
dark color has proven to be satisfactory. 
Amount of Additional Light 
The use of 100 watt lamps with reflectors spaced at six foot intervals, three feet above the plants, is suf- 
ficient light to prohibit bud formation. Light should be applied from midnight to 12:30 a.m. from Au- 
gust 15 to September | and February 15 to April 15. During the period from September | to February - 
|5 it is necessary to use four hours of additional illumination from midnight to 4:00 a.m. or if conve- 
nient from 6:00 p.m. to 10:00 p.m. each evening. 
Temperature Control 
For bud formation a minimum temperature of 60 degrees should be maintained. During the period 
of elongation or where bud formation is not wanted a night temperature near 55 degrees is ideal 
but some investigators find that 50 degrees is satisfactory. When black cloth is started raise the night 
temperature to 60 degrees until color shows, and then it can be lowered. 
When growing a single bench of pompons in a cool house it has been a problem how to increase the 
temperature necessary for bud set. A simple method is when applying black cloth allow the cloth to 
drop to the floor on each side of the bench. Turn on the heat lines under that bench and you will find 
that a 60 to 65 degree temperature can be maintained. 
Timing 
Rooted cuttings previously grown under additional light should be planted directly into the permanent 
location and pinched 21 days later. A soft pinch should be made. The period of elongation or the pe- 
riod which must have additional light will vary with the planting date. October planted cuttings will 
require a longer period to attain their desired height as compared with February planted cuttings. 
Therefore, we have added a schedule of spring flowering chrysanthemums. In this schedule you will 
find the date of planting, the date of pinch, which in all cases is 21 days after planting: The date the 
lights should be off as well. as the shading date are found in this schedule. Remember to apply addi- 
tional light from the day you plant until the respective date given under the heading Lights Off. 
Varieties 
At present the pompon, single and anemone spray type varieties respond the best. Standards often 
times mature with poor flower heads. The pompon varieties will also net you a greater return. The 
varieties found in the schedule are the best for the respective flowering periods. 





