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FLOR A and Education Center
Institute of Food and Agricultural Sciences Research Report
Water Requirements of Three Foliage Plants in Self-Watering Containers Affected by
Indoor Light Intensity and Plant Type
C.A. Conover, Russell Caldwell and K. Steinkamp1
University of Florida,
Central Florida Research and Education Center-Apopk,
CFREC-A Research Report RH-93-15
b. r$ai &Y
SEP 3 01994
University of Florida
Growth, quality and water requirements of Araucaria heterophylla (Norfolk Island
pine), Chamaedorea elegans (parlor palm), Epipremnum aureum (golden pothos) and
Radermachera sinica (China doll) were determined for plants in self-watering containers
maintained indoors under 50, 100, 150 or 200 ft-c for 180 days. Amount of water used was
dependent on light intensity and was specific to plant type. All plants used more water as
light level increased.
Good quality acclimatized foliage plants, if properly cared for, can be maintained
indoors indefinitely. Water stress, often caused by over- or under-watering, damages root
systems which can lessen attractiveness and plant longevity. Self-watering containers,
designed to regulate growing medium moisture levels, are available to interiorscapers and
Interiorscape firms and consumers need more information on watering requirements
of plants in self-watering containers when maintained under different indoor conditions. The
following experiment was conducted to determine water requirements of four foliage plants
in self-watering containers placed under four indoor light intensities.
'Center Director and Professor of Environmental Horticulture, Biological Scientist, and
Technical Assistant, respectively, Central Florida Research and Education Center-Apopka, 2807
Binion Road, Apopka, FL 32703.
The Institute of Food and Agricultural Sciences is an Equal Employment Opportunity Affirmative Action Employer authorized to provide research, educational
information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap or national origin.
COOPERATIVE EXTENSION WORK IN AGRICULTURE, HOME ECONOMICS, STATE OF FLORIDA, IFAS, UNIVERSITY OF FLORIDA,
U.S. DEPARTMENT OF AGRICULTURE, AND BOARDS OF COUNTY COMMISSIONERS COOPERATING.
Materials and Methods
On November 9, 1992, good quality Araucaria heterophylla (Norfolk Island pine),
Chamaedorea elegans (parlor palm), Epipremnum aureum (golden pothos) and Radermachera
sinica (China doll) were transplanted from standard plastic 15 cm production pots into 16.5
cm diameter, 18 cm tall self-watering containers (Decori WatermaticTM, Decor America
Incorporated, Compton, CA 90220). Vergro Container Mix A (Verlite Co., Tampa, FL
33610) was used as the growing medium. Average initial height was 39 cm for Norfolk
Island pine, 49 cm for parlor palm, 22 cm for China doll and 7 cm for golden pothos (vine
On November 13, 1992, plants were placed in interior environment rooms illuminated
with 40 watt cool white fluorescent bulbs. Light intensity indoors was 50, 100, 150 or 200
ft-c, for twelve hours daily. Air temperature ranged from 70 to 800F and relative humidity
was 50 + 5%. There were five replications per light level for each plant type tested.
Plants were fertilized the same day with 1.375 g/L (50 mg N/L) 20-20-20 (N-P20s-
K20) from a stock solution. Watering reservoirs were filled with 100 ml stock solution plus
450 ml water so that plants were fertilized at 0.7 g 20-20-20/6 inch pot/4 months. Water
levels in reservoirs were monitored daily and refilled with 550 ml tap water when empty.
Plant height (vine length of two longest vines per pot for golden pothos) was
measured initially on November 13, 1992 and at monthly intervals thereafter. At three and
six months, plants were graded on the following scale: 1 = dead; 2 = poor quality,
unattractive; 3 = fair quality; 4 = good quality, attractive and 5 = excellent quality, very
attractive. Total volume of water placed in water-holding reservoirs that was utilized was
recorded. Number of days between waterings, number of waterings while indoors, and fresh
weight of foliage were determined when the experiment was terminated.
The self-watering containers worked well, keeping growing medium moist. Norfolk
Island pine quality improved as light intensity increased, from fair, for plants under 50 or
100 ft-c, to attractive for plants under 150 or 200 ft-c (Fig. 1). Both height and fresh top
weight increased slightly with increased light intensity (Figs. 2 and 3).
Parlor palm were attractive and of comparable height under any of the four indoor
light levels tested (Figs. 1 and 2), with an average height of 55 cm. However, the fresh top
weight increase seen with increasing light intensity indicated plants produced more foliage
under higher light intensities (Fig. 3). Although all parlor palms were still attractive after
180 days indoors, fertilization rate appeared inadequate for plants under 150 or 200 ft-c,
which were a lighter green color compared to plants maintained under 50 or 100 ft-c.
Golden pothos under 50 ft-c were of fair quality, while those under 100, 150 or 200
ft-c were judged attractive after 180 days indoors (Fig. 1). Both vine length and fresh top
weight increased when light intensity was increased from 50 to 100 ft-c (Figs. 2 and 3).
For China doll, plant quality, height and fresh top weight increased as light intensity
increased (Figs. 1, 2 and 3). Although only plants under high light were judged attractive
when research was terminated, this light intensity (200 ft-c) was lower than the recommended
minimum for acclimatized China doll plants (225 ft-c).
Water requirements of all plants increased with increases in light intensity and amount
of water needed over the 180 days was dependent on plant type (Fig. 4). For plants
maintained under 200 ft-c, China doll, with the smallest top weight (174.2 g), required
17,500 ml water, while golden pothos, with the largest fresh top weight (460.2 g) required
13,060 ml. Parlor palm needed more water when maintained under 50 ft-c than other plant
types, probably because palms were better able to grow and maintain attractiveness under
this low light condition (indicated by plant grades).
Number of days between waterings depended on light intensity and plant type (Fig.
5). Average number of days between waterings of Norfolk Island pine, golden pothos and
China doll under 50 ft-c was twenty-two days, while parlor palm in the low light averaged
sixteen days between waterings. Although number of days between waterings decreased as
light intensity increased for all plants tested, rate of decrease was also dependent on plant
type. Under 200 ft-c, China doll needed watering an average of every six days, parlor palm
every seven days and Norfolk Island pine and golden pothos both needed watering every
Overall, the self-watering containers worked well. Although China doll was in poor
condition after six months under 50 ft-c, quality of Norfolk Island pine and golden pothos
under 50 ft-c was also lower than quality of plants under higher light.
Water use was related to plant quality and growth. Plants that grew well in the lower
light levels needed more water than plants less suited to those light levels. Water
requirements were affected by interior light intensity, with water needs increasing as light
intensity increased. Water requirements and rate of increased need for water when light
level increased was also dependent on plant type.
Conover, C.A. and R.T. Poole. 1992. Water utilization of six foliage plants under two
interior light intensities. J. Environ. Hort. 10(2):11-113.
Conover, C.A. and R.T. Poole. 1981. Influence of light and fertilizer level and
fertilizer sources on foliage plants maintained under interior environments for
one year. J. Amer. Soc. Hort. Sci. 106:571-574.
Conover, C.A., R.T. Poole and R.W. Henley. 1991. Light and fertilizer recommendations
for the interior maintenance of acclimatized foliage plants. Foliage Digest 16(11):1-4.
Fig. 1. Plant grade of four foliage plant genera in self-watering con-
tainrs after 180 days under four indoor light Intensities.
Norfolk Ine Parlor palm Golden pothos China doll
"L ns "L, "Q **L
Ught Intensity (ft-c) 0 50
S100  150 E 200
ZPlant grade based on a scale of 1 dead, 2 poor quality, unattractive, 3 fair
quality, 4 good quality, attractive, 5 excellent quality, very attractive.
no, L and Q; Results significant at P- 0.01 () or results not significant (ns).
L denotes linear significance, Q denotes quadratic significance.
Fig. 2. Height or vine lengthI of four foliage plant genera in self-watering
containers after 180 days under four indoor light intensities.
125- Ught intensity (ft-c)
0oo- o 100 10 100 1 200
Norfolk pine Parlor palm Golden pohos China doUl
*Y n1 **
zAverage initial height or vine length, measured on November 13, 1992, was
39-cm for Norfolk Island pine, 49-cm for parlor palm, 7-cm for golden pothos
and 22-cm for China doll.
*, and ns; Results show linear significance at P- 0.05 (*), P 0.01 (")
or no ststical significance (ns).
Fig. 3. Fresh top weight of four foliage plant genera, in self-watering
containers after 180 days under four indoor light intensities.
Ught intensity (ft-c)
S50 E 100 [ 150 1 20D
Parlor palm Golden pothos China doll
0* *0 *
zPlant foliage was cut down to level of growing medium surface and weighed on
May 14, 1993, when research was terminated.
"*; Resuts show Inear significance at P- 0.05 (*) or P- 0.01 (*).
Fig. 4. Amount of water required by four foliage plant genera in self-watering
containers during 180 days spent under four interior light intensities'
18000- eight intensity (ft-c) | 50 100 150 200
Norfok pi Parl palm Golden potho* China doll
*LY *O*Q **L **L
ZTotal amount of water wicked up into growling medium from waterwells of self-
watering containers between November 14,1992 and May 14,1993.
Y", ", Land Q; Results significant at P- 0.05 (0 or at P- 0.01 (*). L denotes
linear significance, Q denotes quadratic significance.
Fig. 5. Number of days between waterings for four foliage plant genera in
self-watering containers during 180 days under four indoor light intensitieS.
30 ULight Intensity (ft-c) s50 100 150 200
Norfolk pine Paror palm Golden pothmo China doll
zAverage number of days between watering times based on number of times
empty waterwells of containers were filled with 550 ml water between
November 13, 1992 and May 14,1993.