- /- Influence of Light Duration and Fertilization on Indoor Plant Quality i 8l',
SEP 3 0 1994
R. T. Poole and C.A. Conover'
University of Florida, IFAS University of Florida
Central Florida Research and Education Center Apopka
CFREC-Apopka Research Report RH-91-15
Light levels and fertilizer application rates are important factors influencing the quality
f foliage plants maintained in interior environments. Recommended fertilizer application rates
or foliage maintained indoors vary depending on genera and interior light intensity. Foliage
lants maintained in low light interiors (100 ft-c or less) grow slowly and use little fertilizer
because the rate at which they perform metabolic activities necessary to manufacture food is
lower. Since plants continue to manufacture food when light is present, they are often
luminated for longer periods when maintained indoors under low light, which may help
ounteract effects of lower than recommended illumination levels as long as they are above the
ght compensation point. The following experiment was conducted to study effects of indoor
ght duration and fertilizer rate on quality of foliage plants maintained in an interior
This 3 x 3 factorial experiment, with 5 replications, utilized good quality finished
glaonema 'Silver Queen' ('Silver Queen' aglaonema), Chamaedorea elegans (parlor palm),
'odiaeum variegatum 'Petra' ('Petra' Croton) and Dieffenbachia maculata 'Camille' ('Camille'
ieffenbachia). Plants were grown in 6 inch containers in central Florida, using production
egimes designed to produce acclimatized foliage. Research began on 18 January 1991, when
plants were placed in rooms where they received 100 ft-c from cool white fluorescent lamps for
1, 12 or 16 hours per day. Temperatures in the rooms ranged from 70 to 80F and plants were
vatered once or twice a week as needed. Plants received no fertilizer, or were fertilized with
or 2 g/6 inch pot 19-6-12 Osmocote 3 month release rate fertilizer (Grace/Sierra Co., Milpitas,
'A 95035), applied on 30 January and 9 May 1991. Rates tested (0, 1 and 2 g/6 inch pot),
vere equivalent to 0, 3.75 and 7.5 g/N/ft2/yr, respectively.
1. Conover, C.A. and R.T. Poole. 1991. Light and fertilizer recommendations for indoor
maintenance of acclimatized plants. Univ. of Fla., IFAS, CFREC-Apopka Res. Rpt.
2. Conover, C.A. and R.T. Poole. 1981. Influence of light and fertilizer levels and
fertilizer sources on foliage plants maintained under interior environments for one year.
J. Amer. Soc. Hort. Sci. 106:571-574.
3. Conover, C.A., R.T. Poole and T.A. Nell. 1982. Influence of intensity and duration
of cool white fluorescent lighting and fertilizer on growth and quality of foliage plants.
J. Amer. Soc. Hort. Sci. 107(5):817-822.
4. Manaker, G.H. 1981. Light. p.66-68. In: Interior Plantscapes, Prentice-Hall,
Englewood Cliffs, N.J.
5. Turner, M.A., D.L. Morgan and D. Wm. Reed. 1987. The effect of light quality and
fertility on long term interior maintenance of selected foliage plants. J. Environ. Hort.
6. Wright, R.D. 1986. The pour-through nutrient extraction procedure. HortScience
iLV11I t JiCUL JIUAUUL UIAILI A. JA JI A L
Light duration (hrs)Y A. 'Silver C. C. D.
Queen' elegans 'Petra' 'Camille'
8 4.6 4.6 4.1 3.2
12 4.9 4.6 4.3 3.7
16 4.9 4.3 4.3 3.9
linear ns ns ns **
quadratic ns ns ns ns
zPlants were graded on a scale of 1 = poor quality, unsalable, 3 = fair quality, salable and 5
= excellent quality on 19 July 1991. Experiment terminated on 22 July 1991.
YPlants received 100 ft-c light from cool white fluorescent bulbs 8, 12 or 16 hours per day.
"ns or **; Results nonsignificant or significant at P = 0.01.
1l ljllz 1 .lall lllalll
Light duration (hrs)y
A. 'Silver Queen' C. elegans C. 'Pet
8 1.5 2.7 1.0
12 1.0 3.3 1.9
16 2.7 6.4 2.2
linear ns *
quadratic ns ns ns
g 19-6-12/6" pot"
0 1.9 2.7 2.4
1 1.2 4.7 1.3
2 1.7 4.9 1.4
iaoie 3. mectncal conaucnvity (tmnos/cm) ana pti or leacnate trom pots containing
rooms with various fertilizer rates from 18 January until 22 July 1991.
29 January 9 May
g 19-6-12/6" potz
g 19- pH imhos/cm pH /Lmhos/cm
0 6.8 815 7.7 178
1 7.0 578 7.6 288
2 6.9 629 7.4 598
linear ns ns **
quadratic ns ns ns *
z19-6-12 Osmocote 3 month release rate fertilizer applied 30 January and 9 May 1991. Rat
equivalent to 0, 3.75 and 7.5 g/N/ft2/yr, respectively.
Yns, or **; Results nonsignificant or significant at P = 0.05 or P = 0.01, respectively.