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/' Severity of Necrosis of Spathiphyllum 'Petite' Foliage Grown
Under Various Air Temperatures, Fertilization Rates, and Irrigation
R. T. Poole and C. A. Conover1
University of Florida, IFAS
Central Florida Research and Education Center Apopka r
CFERC-Apopka Research Report, RH-90-18 I
Spathiphyllum 'Petite' (Petite or Bennett spathiphyllum) responds '
well to growth regulators, making it a suitable flowering foliage crop for
4 to 10-inch pot production. Since this is one of the more commonly grown
cultivars of spathiphyllum readily controlled by growth regulators,
Spathiphyllum 'Petite' has the potential to become more widely utilized by
the foliage plant industry. Unfortunately, this spathiphyllum hybrid is
much more-susceptible to necrosis of the leaf tips than less versatile
cultivars. Florida growers have noticed 'Petite' tends to develop this
condition much more readily during hot summer months, therefore some
producers have limited production to the cooler season. The following
research attempts to isolate the causal factors of 'Petite' tip necrosis
and find ways to overcome this tendency.
This 4x3x2 factorial experiment with four replications was initiated
on August 24, 1989, when liners of Spathiphyllum 'Petite' were placed in
6-inch plastic pots containing Vergro container mix (Canadian sphagnum peat
moss, coarse grade vermiculite and perlite without superphosphate, Verlite
Co., Tampa, FL 33680), amended with 1 lb. Micromax (Sierra Chemical Co.,
Milpitas, CA 95035) and 7 lbs. dolomite/yd.3. Plants were grown in
glasshouses where they received 1100 ft-c maximum light intensity, air
temperature ranges of 59-82, 64-88, 70-93 or 75-990F, and were watered once
or twice weekly. On September 6, and again on December 18, 1989, plants
were fertilized with 19-6-12 3-month release rate Osmocote (Sierra Chemical
Co., Milpitas, CA 95035) at rates of 2, 4 or 6 g/6-inch pot. Height of
test plants was recorded monthly, starting September 7, 1989, and ending
March 13, 1990. Plant grade, and pH and micromhos/cm of the leachate,
determined by the pour through nutrient extraction method, were recorded at
the conclusion of the experiment in March 1990.
Air temperature, fertilization rate and irrigation frequency all
interacted to create conditions favorable for tip necrosis development.
Poorest quality plants having the most tip necrosis were produced with the
highest temperature ranges and fertilizer rates tested, and watered only
once a week (Table 1). Best quality 'Petite' plants having no tip necrosis
were produced utilizing the more moderate temperature ranges, the highest
fertilization rate tested, and watered twice a week.
Higher air temperatures, up to a point, cause plants to increase
their photosynthesis and respiration rates. This increase in metabolic
rate creates the potential for excess metabolites to collect in delicate
new tissue forming at the growing tips of plants. Excess solute
accumulation in developing tissues may cause the damage resulting in tip
Professor of plant Physiology, and Professor and Center Director,
respectively. Central Florida Research and Education Center, 2807 Binion
Road, Apopka, FL 32703.
necrosis. Florida producers can predispose the plants to this problem in
the summertime, when high air temperatures are unavoidable, by combining
higher fertilization levels with infrequent watering schedules. As the
growing medium dries its' soluble salts become more concentrated,
especially in lightweight growing media, where a 50% loss in soil moisture
approximately doubles the salts concentration. Soluble salts levels of the
leachate from the media of pots growing 'Petite' were highest when plants
received the higher temperature ranges and fertilization rates, and were
watered only once a week (Table 2). This production regime also produced
the lowest quality plant material having the most tip necrosis. Frequent
waterings leach soluble salts from the growing media, hence fewer ions are
incorporated into the transpiration stream, so tissue damage is less likely
Data recorded for height support these findings. Tallest plants
were produced utilizing a temperature range of 70 to 930F and watered twice
a week, and also a temperature range of 59 to 820F and watered once a week
(Table 3). The highest temperature regime tested, combined with only one
watering per week produced the shortest plant material.
In analyzing the data collected from this test we can make some
recommendations for growing Spathiphyllum 'Petite':
1. Install adequate ventilation for use during the hot summer
months and make sure it is working properly. This will help keep
the temperature within the recommended levels for foliage plant
production. The recommended temperature range for spathiphyllums is 65
2. Apply the recommended rate for the type of fertilizer used when
growing spathiphyllum species. Example: When using 19-6-12 3-month
release rate fertilizer, and spathiphyllum are growing in 6-inch pots,
the recommended fertilization rate is 4.0 g/pot/3-months. These
fertilization rate recommendations are listed in CFREC-A Research
Report RH-90-1, Light and Fertilizer Recommendations for Production of
Acclimatized Potted Foliage Plants.
3. Keep soil in pots moist during the hot summer months by increasing
irrigation frequency. When plants are grown under the recommended
temperature and fertilization ranges, and soil is kept moist, no
tip necrosis develops.
4. Soluble salts levels should be closely monitored when they are
utilized as a factor in determining fertilizer application times and
rates. Monthly testing will help individual producers establish a
baseline to determine optimum soluble salts levels. Dangerously high
salts concentrations can then be recognized early and media can be
leached to remove excess ions before foliage damage occurs.
1. Chase, A.R. and R.T. Poole. 1984. Severity of acephate
phytotoxicity on Spathiphyllum Schott. cv. Clevelandii as influenced
by host nutrition and temperature. J. Amer. Soc. Hort. Sci.
2. Conover, C.A. and R.T. Poole. 1984. Light and fertilizer
recommendations for production of acclimatized potted foliage
plants. Agri. Res. Ctr.-Apopka AREC-A Res. Rpt. RH-84-7.
3. Hipp, B.W., P.F. Colbaugh and M. DiLeo. 1979. Influence of fertility
and moisture level on growth of Chlorophytum. HortScience
4. Joiner, J.N., C.A. Conover and R.T. Poole. 1981. Section of
chapter on Nutrition and Fertilization in textbook, Foliage Plant
Production, J.N. Joiner, University of Florida, Editor,
Prentice-Hall, Englewood Cliffs, NJ pp.256-268.
5. Poole, R.T. 1981. Soluble salts interpretation. Foliage Digest
6. Poole, R.T., C.A. Conover and A.R. Chase. 1985. Soluble salts
interpretation for ornamental crop production. Proc. Trop. Reg.
Amer. Soc. Hort. Sci. 27:33.
7. Wright, R.D. 1986. The pour-through nutrient extraction
procedure. HortScience 21(2)227-229.
Table 1. Interaction of temperature range, fertilization rate and watering
frequency on plant grade of Spathiphyllum 'Petite' March 9, 1990.
Plants watered once a week Plants watered twice a week
Fertilization rate (gms)
2 4 6 2 4 6
Range (oF) Plant GradeY
59-82 3.3 4.3 4.3 3.0 4.0 4.5
64-88 2.8 3.8 3.4 3.0 4.4 4.9
70-93 2.5 2.9 2.5 2.9 4.3 4.5
75-99 2.9 3.0 2.1 3.1 3.9 3.8
"Osmocote 19-6-12 3-month release rate fertilizer surface applied September 6
and December 18, 1989.
YPlants graded on a scale of 1 = poor quality, unsalable, 3 = fair quality,
salable and 5 = excellent quality plant material.
Interaction of temperature range, fertilization rate and watering
on soluble salts levels of the leachate from pots
containing Spathiphyllum 'Petite' March 9, 1990.z
Plants watered once a week
Fertilization rate (gms)
2 4 6
Plants watered twice a week
Fertilization rate (gms)
2 4 6
Range (OF) micromhos/cm
59-82 360x 583 1152 254 383 583
64-88 281 463 1917 352 425 568
70-93 830 3552 9658 317 301 826
75-99 477 1527 7520 437 417 674
"Results significant at the 0.01% level.
YOsmocote 19-6-12 3-month release rate fertilizer surface applied September 6,
and Deccember 18, 1989.
xSoluble salts of the leachate were measured using the pour-through method.
Table 3. Interaction of air temperature range and watering frequency
of Spathiphvllum 'Petite' March 13, 1990.z
Air Temperature Range (oF)
Watering Frequency Height (gms )
once a week 32.3 28.8 26.9 26.4
twice a week 30.7 31.5 32.3 31.8
'Results significant at the 0.01% level.