Group Title: ARC-A research report - Agricultural Research Center-Apopka ; RH-81-1
Title: Guide for fertilizing tropical foliage plant crops
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Permanent Link:
 Material Information
Title: Guide for fertilizing tropical foliage plant crops
Series Title: ARC-A research report
Physical Description: 9 p. : ; 28 cm.
Language: English
Creator: Conover, Charles Albert, 1934-
Poole, R. T ( Richard Turk )
Agricultural Research Center (Apopka, Fla.)
Publisher: IFAS, University of Florida, Agricultural Research Center-Apopka
Place of Publication: Apopka Fla
Publication Date: 1981
Subject: Foliage plants -- Fertilizers -- Florida   ( lcsh )
Tropical plants -- Fertilizers -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Statement of Responsibility: C.A. Conover and R.T. Poole.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00065934
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 70913730

Full Text


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source

site maintained by the Florida
Cooperative Extension Service.

Copyright 2005, Board of Trustees, University
of Florida


[ .T 7:. ,:;C. A. Conover and R. T. Poole
SLIFAS University of Florida
Agricultural Research Center-Apopka
:: ARC-A Research Report RH-81-1

f.erti1 zers are.very important to production of tropical foliage
p ants, yet contribute-less than 1% of total production costs. Because
of their importance during production and small contribution to total
costs, the establishment of ideal nutritional programs should be the goal
of every grower.

An understanding of the potting medium is necessary before fertilizer
programs can be developed. Of great important is pH, since it controls
release of nutrients provided in the fertilizer program. If pH is too low,
it will reduce conversion of ammonia to nitrate nitrogen, while high pH
levels reduce availability of most microelements. Most foliage plants grow
best when the pH is between 5.5 and 6.5, although some such as Maranta and
Calathea prefer a range of 5.5 to 6.0. It is desirable to adjust pH level
prior to planting crops.

Low pH levels can be raised in potting media by addition of liming
material such as dolomite or calcium carbonate, while high pH levels can be
lowered by addition of sulfur. The amount of liming material or sulfur to
change pH depends on amount of organic material present and its beginning
pH; therefore, small amounts of lime or sulfur will change pH of sandy potting
media while larger amounts are needed to change pH of pure peat. Table 1
provides a guide for adjusting pH levels of potting media during preparation.

Once foliage plants are growing in a potting medium, elevating pH is
difficult. The best material to raise pH is calcium hydroxide (hydrated
lime) which can damage plants unless applied in solution of 1 lb/100 gal or
less to 100 ft2 of surface area (pots or benches). This can be followed by
another treatment 4 weeks later if pH has not reached desired levels. Calcium
carbonate applied to the potting medium surface and watered in will also raise
pH, but it usually takes several weeks before its effect is noticeable. Where
pH levels are too high, sulfur can be applied at the rate of 1 lb/100 ft2 to
lower pH. Do not apply sulfur more often than every 4 weeks until the desired
level is reached, as plant damage may result from rapid pH changes.

Soluble Salts

Although most components used in Florida potting media are low in total
soluble salts, salts should be determined prior to medium preparation. Special
fertilizer programs can be designed for media with high salts to limit addition
of unnecessary fertilizer ions or apply smaller amounts of fertilizer on a more
frequent basis to reduce damage.


In most potting media used to grow foliage plants, microelements are
needed. Where good mixing equipment is available, microelements should be

thoroughly incorporated into the medium At time of mixing. Many products
are available for this purpose; MicromaxUR and Perk R have given excellent
results in experimental plots when added at the rate of 1 to 1 1/2 Ibs/yd3.

Where micronutrients cannot be incorporated into the potting medium
they should be added separately or incorporated into the fertilizer program,
either as a periodic application or along with every fertilizer application.

On an annual or monthly basis, Table 2 provides the average amounts of
6 microelements that are needed to grow good quality foliage plants. If a
micronutrient mix is added to the potting medium, the annual rates should not
be started until 6 months after potting.

Incorporation of dolomite and a micronutrient mixture into the potting
medium supplies calcium and magnesium frAm dolomite and sulfur plus
micronutrients from Micromaxu) or Perk(B If a different source of
micronutrients is used, check to be sure sulfur is in the mixture, or add
sulfur, as this is usually the only source except for sulfur in water,


Incorporation of superphosphate into potting media used to grow many
crops has been a common practice. Research, however, on foliage plants has
shown that preincorporation of phosphorus is unnecessary for quality foliage
plant production and can result in serious phytotoxicity on some foliage
genera from excessive fluoride levels. Superphosphate contains 1 to 2%
fluoride as a contaminant and this will cause foliar damage on Calathea,
Chlorophytum, Cordyline, Dracaena, Maranta, and Yucca. Since no unique
benefit has been observed from superphosphate additions to potting media used
for production of foliage plants, its use is discouraged.

Fertilizer Ratios

Relative levels of nitrogen, phosphorus and potassium in a fertilizer
analysis are referred to as the N-P205-K20 ratio. Research in this area has shown
that foliage plants grow very well on a 1:1:1 ratio, such as in an 8-8-8 or
20-20-20 fertilizer analysis, but just as well on a 3:1:2 ratio, such as a
9-3-6 or 18-6-12 analysis. The benefits of using the 3:1:2 ratio are reduced
fertilizer costs per unit of nitrogen and lower total soluble salts levels
which improve a plant's ability to acclimatize to interior environments. For
these reasons, a 3:1:2 ratio fertilizer is suggested for foliage plant
production where soilless potting media are utilized. When potting media are
used that include clay containing soils, it is suggested that a 1:1:1 ratio
be used to prevent reduced availability of phosphorus and potassium.

Fertilizer Levels

Selection of the proper amount of fertilizer to apply to a specific
foliage crop varies with the growing environment. Some major factors
influencing fertilizer level include light intensity, temperature, rainfall
or irrigation level, and ability of potting medium to retain nutrients (cation
exchange capacity).


Light levels or intensities used for production of foliage plants must
be selected for optimum plant growth as well as effect on acclimatization.
Best growth can be obtained at light intensities that provide highly
acclimatized plants. See Table 3 to obtain information on suggested
fertilizer levels for a wide variety of foliage plants when grown under
recommended light intensities. If plants are grown under higher light
intensities, even full sun for plants like schefflera or areca palms, the
suggested fertilizer levels will have to be increased by 50 to 100% (this
is not recommended for production of acclimatized plants). If lower light
intensities are present, suggested fertilizer level can be reduced by as
much as 25%.

Temperature has a strong effect on fertilizer needs of foliage plants.
Most foliage plants grow slowly, if at all, when soil temperatures drop
below 60F and night air temperatures are 650F or below. Thus, maintenance
of standard fertilizer levels during this time is unnecessary and can often
be reduced 50%. Slow release fertilizers are generally only partially
available to plants during periods when potting media are cold, but become
available as media warm; therefore, rates can be adjusted with such
fertilizers by lengthening the time between application periods. During
high temperature periods (850 to 950 days and 750 to 850 nights) foliage
plants grow rapidly and can utilize slightly more fertilizer than listed
rates. A general rule that will account for cool and warm season foliage
production is to reduce suggested fertilizer levels by 25% during December -
February and raise them by 25% from June September.

Rainfall or irrigation level effects amount of fertilizer leached from
potting media. Where excessive levels of water are applied through irrigation
or where plants are grown under shadecloth and are open to periods of heavy
rainfall, irrigation levels can be adjusted downward to reduce leaching.
Addition of extra fertilizer is, however, desirable after periods of excessive
rainfall (4 to 6 inches over a one week period) to compensate for leaching.

Nutrient retention ability (cation exchange capacity) of potting media used
to grow foliage plants is important in establishing fertilizer levels.
Fertilizer levels in Table 3 are based on utilization of potting media
composed primarily of organic components with high cation exchange capacity.
Examples of such potting media include (1) 75% peat moss 25% sand, (2) 50%
peat moss 25% pine bark 25% cypress shavings, and (3) 80% peat moss -
20% perlite, styrofoam or similar materials. Potting media composed of greater
amounts of sand, perlite, styrofoam or pine bark may require slightly higher
fertilizer levels.

Fertilizer Sources

Selection of a fertilizer includes not only the form of the fertilizer
such as liquid, granular or slow release, but also the source of the nutrients

Nutrient sources have been little considered in selection of fertilizers
by most foliage producers. For example, nitrogen is presently available
in fertilizer from three primary sources: nitrate (N03-), ammoniacal
(NH4+), and urea (CO(NH2)2). In years past most fertilizers contained 20
to 50% nitrate nitrogen and the remainder came from ammoniacal or urea
forms. In recent years fertilizer formulators have substituted urea for
much of the nitrate nitrogen because of its lower cost.

Although information has been published on the influence of nitrogen
source on several flower crops, little is available on foliage plants.
Limited research by this research center has not shown much difference in
growth or quality of foliage plants when grown on the presently recommended
50:50 ratio of nitrate to ammoniacal or urea nitrogen or a combination
higher in urea. Since research on many floricultural crops (including
leatherleaf fern) shows benefits of including nitrate nitrogen as one of
the nitrogen sources, we still suggest using at least 25% nitrate in
combination with ammoniacal or urea nitrogen.

Research has not been conducted on effects of different sources of
other macro-ormicronutrients on foliage plant production. Thus, the major
consideration in their selection should be their effect on pH and availability
of nutrients (Table 4).

Nutrient form selection is influenced by method of fertilizer application
and economics. Factor that influence selection of liquid or slow release
fertilizers is covered in "Effective and Economical Fertilizer Considerations",
Agricultural Research Center-Apopka Research Report RH-80-3.

Fertilizer Application Frequency

Liquid fertilizers can be applied with each irrigation, weekly or every
other week. Wider applications (such as once each 4 weeks) will result in
reduced growth and lower quality.

Slow release fertilizers have a specified release period, such as 2 to 4,
3 to 4, 8 to 9 months or more. The release rate for slow release fertilizers
is usually calculated for a soil temperature near 70F. During periods when
potting media are near 650F or lower, the release rate will be slower, or if
temperatures reach 80 to 900F, will be much faster. These factors must be
considered when using slow release fertilizers in Florida, since release rate
of a 3 to 4 month material may be 2 to 3 months in the heat of summer or 4 to 5
months during a cool winter.

Fertilizer Rates

Suggested rates for various areas, pot sizes and sources are shown in
Tables 5-8. If fertilizer is to be applied as a ppm solution check rates
against footnotes on Tables 5-6. Suggested N, P and K levels in ppm for
continuous application are 150 ppm N, 50 ppm P and 100 ppm K.

Table 1. Approximate amount of materials required to change pH
of potting mixtures.

Pounds per cubic yard to change acidity to pH 5.7 for:
Beginning 50% Peat 50% Peat 100% Peat
pH 50% Sand 50% Bark

Add dolomitic lime or equivalent amount of calcium to
raise pH to 5.7:

5.0 1.7 2.5 3.5
4.5 3.7 5.6 7.4
4.0 5.7 7.9 11.5*
3.5 7.8 10.5* 15.5*

Add sulfur or acidifying mixture to lower pH to 5,7:

7.5 1.7 2.0 3.4
7.0 1.2 1.5 2.5
6.5 0.8 1.0 2.0
Additions of more than 10 pounds of dolomite per cubic yard often
caused micronutrient deficiencies.

Table 2. Suggested annual application rates of micronutrients for
foliage plants.

Rate of application
Element gm/1000 sq ft/yr gm/1000 sq ft/mo Ib/A/yr

Boron (B) 5.2 0.43 0.5
Copper (Cu) 52.0 4.33 5.0
Iron (Fe) 208.0 17.33 20.0
Manganese (Mn) 104.0 8.67 10.0
Molybdenum (Mo) 0.2 0.02 0.02
Zinc (Zn) 52.0 4.33 5.0

Table 3. Suggested nutritional levels for production
foliage plants.

of some potted acclimatized

Fertilizer requirement
lbs/1000 sq ft/yr1
Light intensity
Botanical name (foot-candles) N P205 K20

Aeschynanthus pulcher
Aglaonema spp.
Aphelandra squarrosa
Araucaria heterophylla
Asparagus spp.
Brassaia spp.
Calathea spp.
Chamaedorea elegans
Chamaedorea erumpens
Chlorophytum comosum
Chrysalidocarpus lutescens
Cissus rhombifolia
Codiaeum variegatum
Coffea arabica
Cordyline terminalis
Dizygotheca elegantissima
Dieffenbachia spp.
Dracaena deremensis (cultivars)
Dracaena fragrans (cultivars)
Dracaena marginata
Dracaena other species
Epipremnum aureum
Ficus benjamin
Ficus elastica (cultivars)
Ficus lyrata
Fittonia verschaffeltii
Gynura aurantiaca
Hedera helix
Hoya carnosa
Maranta spp.
Monstera deliciosa
Nephrolepis exaltata (cultivars)
Peperomia spp.
Philodendron Selloum
Philodendron spp.
Plea spp.
Polyscias spp.
Sansevieria spp.
Schlumbergera truncata
Spathiphyllum spp.
Syngonium podophyllum
Yucca elephantipes


1Based on a 3-1-2 ratio fertilizer source if growing
phosphorus and potassium, they should be added at the
i.e., use a 1-1-1 ratio fertilizer source.

medium is known to fix
same rate as nitrogen -

Table 4. Analysis and pH characteristics

of some common fertilizer

Analysis Effect Speed of pH
Name of material N-P205-K20 on pH reaction

Ammonium sulfate (NH4) S04 20-0-0 Very acid Rapid
Calcium nitrate Ca(NO3)2-2H20 15-0-0 Basic Rapid
Potassium nitrate KNO3 13-0-44 Neutral Rapid
Ammonium nitrate NH4NO3 33-0-0 Acid Rapid
Urea CO(NH2)2 46-0-0 S1. acid Rapid
Mono-ammonium phosphate NH4H2PO4 11-48-0 Acid Rapid
Ca(H2PO4)2+CaS04 0-20-0 Neutral Medium
Potassium chloride KC1 0-0-60 Neutral Rapid
Potassium sulfate K2SO4 0-0-50 Neutral Rapid
Dolomite MgCO3-CaCO3 --- Basic Very slow
Limestone CaCO3 --- Basic Slow
Hydrated lime Ca(OH)2 --- Basic Rapid
Gypsum (calcium sulfate)CaSO4 --- Neutral Medium
Sulfur --- Acid Slow
Epsom salts (magnesium sulfate)
MgSO4-7H20 --- Neutral Rapid
Urea forma dehyde 38-0-0 Sl. acid Slow

Table 5. Amounts of 9-3-6 fertilizer to
specific crops (see Table 3).

use to supply suggested fertilizer levels for

lb/1000 sq ft/yr lb 9-3-6/1000 gms 9-3-6/pot-month1
N P205 K20 Ib N/A/yr sq ft/month 4" 6" 8" 0" 12"

14 5 9 600 12.82,3 0.4 0.9 1.8 2.6 4.0
20 7 13 900 19.1 0.7 1.3 2.6 4.0 5.9
28 9 19 1200 25.6 0.9 1.8 3.5 5.3 7.9
34 11 23 1500 31.9 1.1 2.2 4.4 6.6 9.9
41 14 27 1800 38.4 1.3 2.6 5.3 7.9 11.9

One teaspoon 9-3-6 equals approximately 5 gms.
2If fertilizing with each irrigation is desired, divide by expected number of irriga-
tions during the month.
One quarter ifch of 100 ppm N applied ten times monthly equals approximately 12.8 Ibs
9-3-6/1000 ft .

Table 6. Amounts of 20-20-20 fertilizer to use to supply suggested fertilizer levels O
for specific crops (see Table 3).

b/1000 sq ft/yr lb 20-20-20/1000 gms 20-20-20/pot month1
N P205 K20 lb N/A/yr ft2/month 4" 6" 8" 10" 12"

14 14 14 600 62,3 0.2 0.4 0.8 1.2 1.8
20 20 20 900 9 0.3 0.6 1.2 1.8 2.7
28 28 28 1200 12 0.4 0.8 1.6 2.4 3.6
34 34 34 1500 15 0.5 1.0 2.0 3.0 4.5
41 41 41 1800 18 0.6 1.2 2.4 3.6 5.4

One teaspoon 20-20-20 equals approximately 5 gms.
2If fertilizing with each irrigation is desired, divide by expected number of
irrigations during the month.
30ne quarter inch of 100 ppm N applied ten times monthly equals approximately 6 Ibs
20-20-20/1000 ft2.

Table 7. Amounts of 14-14-14 Osmocotel to use to supply suggested fertilizer levels
in various sized pots for specific crops (see Table 3).

lb/1000 sq ft/yr Surface application
N P205 K20 1.b N/A/yr gmz/pot/3 months
4" 6" 8" 10" 12"

14 14 14 600 1.0 2.0 4.0 6.0 9.0
20 20 20 900 1.5 3.0 6.0 8.0 13.5
28 28 28 1200 2.0 4.0 8.0 12.0 18.0
34 34 34 1500 2.5 5.0 10.0 15.0 22.3
41 41 41 1800 3.0 6.0 12.0 18.0 27.0

1Sulphur coated slow release formulations can be substituted at equivalent rates.
For urea formaldehyde slow release formulations increase rates by 25%.
20ne level teaspoon = approximately 5 gms.

Table 8. Amounts of 19-6-12 Osmocotel to use to supply suggested fertilizer levels
in various sized pots for specific crops (see Table 3).

lb/1000 sq ft/yr Surface application
N P205 K20 lb N/A/yr gm2/pot/3 months
4" 6" 8" 10" 12"

14 5 9 600 0.7 1.7 2,8 4.5 6.4
20 7 13 900 1.0 2.5 4.3 6.7 9.6
28 9 19 1200 1.4 3.3 5.7 9.0 12.7
34 11 23 1500 1.8 4.2 7.1 11.2 15.9
41 14 27 1800 2.1 5.0 8.5 13.9 19.1

1Sulphur coated slow release formulations can be substituted at equivalent rates.
For urea formaldehyde slow release formulations increase rates by 25%.
20ne level teaspoon = approximately 5 gms.

r -,,

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