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Copyright 2005, Board of Trustees, University
Reaction of Seven Foliage Plants toSodium Hypochlorite Fumes o Drenches
L fbn science
R.T. Poole and R.W.Henley 3 0 19*
University of Florida, Universitof Fid
Central Florida Research and Education Center-Apopka f lori
CFREC-Apopka Research Report RH-92-25
Sodium hypochlorite (NaOC1) is an effective algicide often used to clean greenhouse
structures. Solution fumes do not seem to harm foliage plants, but plants are usually exposed
to the algicide briefly during production, depending on rate of algae regrowth. NaOC1, in low
concentrations, is also commonly used to control algae growth in ebb and flow systems with no
detrimental effects. However, when NaOC1 is used in swimming pool water quality
maintenance, plantscapes around spas and pools are constantly exposed to NaOCI, in the air and
from splashing, at higher rates than in closed watering systems. The two experiments described
below were conducted to determine the reaction of seven foliage plants receiving a one-time
sodium hypochlorite drench or constant fumes for one week.
Materials and Methods
Species tested were Dizygotheca elegantissima (false aralia), Dracaena deremensis 'Janet
Craig' ('Janet Craig' dracaena), Ficus benjamin (weeping fig), Ficus elastica 'Robusta'
('Robusta' rubber tree), Homalomena 'Emerald Gem' ('Emerald Gem' homalomena),
Philodendron scandens oxycardium (heart-leaf philodendron) and Polyscias fruticosa (Ming
aralia). All were good quality ready-for-sale plants obtained from local nurseries. Plants had
been grown in 4, 6, 8 or 10-inch pots, depending on species, using various commercial growing
Experiment 1 measured plant sensitivity to NaOCI solution fumes. Upon arrival at
CFREC-Apopka, plants were placed in 10 x 10 x 8 ft rooms for a 1 week period. Light
intensity in rooms, from cool white fluorescent lights, was 200 ft-c and air temperature was
maintained at 75F. Plants in rooms spent the week enclosed in sealed airtight 1 x 1 x 2 ft glass
containers with a 100 ml beaker holding 50 ml sodium hypochlorite solution (5.25% active
ingredient by weight) or unenclosed on floor of rooms.
Experiment 2 tested reactions to sodium hypochlorite drenches. Soon after arrival at
CFREC-Apopka, plants were placed in 10 x 10 x 8 ft rooms, adjacent to rooms used in
'Professor of Plant Physiology, and Professor of Environmental Horticulture and Extension
Specialist, respectively, Central Florida Research and Education Center-Apopka, 2807 Binion
Road, Apopka, FL 32703.
-emperiment 1, where they were maintained for a 1 week period. As in experiment 1, light
intensity in rooms was 200 ft-c and air temperature was 75 F.
Growing medium of plants was drenched with 20% of a 5% sodium hypochlorite solution
or tap water. Amount of solution each plant received was determined by pot size. Plants in 4-
inch pots received 50 ml, 6-inch pots got 100 ml, 8-inch pots got 150 ml and plants in 10-inch
pots were drenched with 200 ml of 20% of a 5% sodium hypochlorite solution or tap water.
After one week in rooms, plants were moved to a greenhouse where maximum light
intensity was 1500 ft-c and air temperatures ranged from 65 to 90F. Plants were maintained
in greenhouses for up to two months in order to evaluate effects of treatments. When visible
signs of damage were fully developed on individual species that were sensitive, those plants were
graded. Plant grades were determined based on a scale of 1 = dead, 2 = poor, unsalable, 3
= fair, salable, 4 = good quality and 5 = excellent quality. Inspection and evaluation dates
are given in Table 1.
In experiment 1, NaOCI fumes did not appear to harm any of the 7 species tested.
Plants enclosed with fumes were not visibly damaged and quality was unaffected by treatment.
Results of experiment 2 showed recent and new growth on 'Emerald Gem' homalomena
and Ming aralia receiving drenches was necrotic. Necrosis was severe enough to degrade
quality of both species from excellent to poor. The 5 other species tested were unaffected by
Based on these experiments, 'Emerald Gem' homalomena and Ming aralia would be
inappropriate for inclusion in plantscapes situated close enough to be splashed with chlorinated
pool or spa water.
Dates when fume and drench treatments were initiated and dates when foliage was inspected for damage for the eight
species used two experiments initiated on 30 April and concluded on 30 June 1992.
Plant Date treated Date inspected
Dizygotheca elegantissima 30 Apr to 7 May 10 Jun
Dracaena deremensis 'Janet Craig' 27 May to 4 Jun 10 Jun
Ficus benjamin 1 Jun to 8 Jun 10 Jun
Ficus elastica 'Robusta' 23 Apr to 30 Apr 10 Jun
Homalomena 'Emerald Gem' 30 Apr to 7 May 10 Jun
Philodendron scandens oxycardium 2 Jun to 9 Jun 30 Jun
Polyscias fruticosa 16 Apr to 23 Apr 28 Apr
zPlants placed in rooms for one week were either drenched with 20% NaOCI solution when placed in rooms, enclosed in airtight glass
containers with 50 ml NaOCL for the entire 7 day period or were part of control groups which received no NaOCI.