Year-Around Flowering of Chrysanthemums 
Since the advent of daylength and temperature con- 
trol, we have seen chrysanthemum cut flowers on the 
markets every month since 1946, thanks to our never- 
tiring research workers in various federal and state 
institutions. Season has been eliminated, and the 
flowering time can be accurately controlled, 
Response Group 
Prior to year-around flowering of chrysanthemums, we 
referred to varieties as to their natural flowering date. 
Now that year-around flowering is in general use, we 
refer to a variety as to its response to short-day treat- 
ment. When we say 9 week response, we mean that 
it will bloom 9 weeks after the short-day treatment is 
started. A 1|3-week group requires 13 weeks after 
short-day treatment is started, and so on with all the 
other response groups. 
Daylength Control 
When chrysanthemums are grown around the year, 
it is very necessary that we know when to apply shade 
or light to make the plants respond as we desire. The 
following schedule will give you the proper dates for 
lighting and shading for each response group. 
YEAR-ROUND LIGHTING AND SHADING SCHEDULE 
Lighting to Start 
in Fall 
Response Group Shading to 
Stop in Fall 
7 week Aug. 29 July 
8 week Sept. 5 July 
9 week Sept. 12 Aug. 
10 week Sept. 19 Aug. 
11 week Sept. 26 Aug. 
12 week Oct) 3 Aug. 
13 week Oct. 10 Aug. 
14 week Oct. 17 Sept. 
Lighting 
To prevent formation of flower buds, the light intensity 
must be 10 foot-candles. 
When lighting an entire house, the lamps should be 
installed in the ridge of the house. Usually we figure 
that it requires 1!/> watts per sq. ft. of area covered; 
that includes benches and walks. For smaller installa- 
tions, the spacing given below will be satisfactory for 
a bench 42 inches to 48 inches wide: 
60-watt lamps in a reflector, spaced 4 feet apart, 
2 to 3 feet above the tops of the plants. 
100-watt lamps in a reflector, spaced 6 feet apart, 
2 to 3 feet above the tops of the plants. 
Shading to Start Lighting to 
in Spring Stop in Spring 
18 Apr. 11 May 30 
25 Apr. 4 May 23 
1 Mar, 28 May 16 
8 Mar. 21 May 9 
15 Mar. 14 May 2 
22 Mar. 7 Apr. 25 
29 Feb. 28 Apr. 18 
5 Feb, 21 Apr. 11 
Lights must be used according to the schedule 
above. It has been found that best results are secured 
by interrupting the night. Begin lighting at 10 p.m. for 
the number of hours shown below: 
ADDITIONAL LIGHTING SCHEDULE 
2 Hours during the months of August, April and May. 
3 Hours during the months of September, October and 
March. 
4 Hours during the months of November and February. 
5 Hours during the months of December and January. 
