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or recommendations. These texts
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Copyright 2005, Board of Trustees, University
of Florida









INFLUENCE OF NUTRITION ON FOLIAGE QUALITY AND LONGEVITY


By

Charles A. Conover
Agricultural Research Center Apopka
Mimeo Report ARC-A 1972-3


Nutrition of tropical foliage plants has a major influence on growth

rate, quality and longevity. Growth rate has a major effect on profit

of a particular foliage plant to growers and ultimate o p ?nwr "

Therefore, slow growing varieties cost more because t y utilize labor

and space for a larger time span and growers increase fertility levels

to reduce production costs. Quality of foliage plants ks also vqer oF

important, because appearance is a prime factor in stimulat4nghtl aes.

The appearance, can be altered considerablyby fertilization, which

influences plant and leaf size as well as color.

Longevity of foliage is of prime interest to consumers and determines

consumer satisfaction, and therefore, repeat sales. During the first

few months in the home, plants are influenced to a considerable degree

by the fertility regimes of the grower and can affect longevity. Growth

rate, quality and longevity of foliage plants may be increased or decreased

by changing nutrition. Therefore, for any given situation there is a

desirable nutritional range that will provide the grower and consumer

greatest satisfaction.


Growth

Maximum growth rate can be obtained with many foliage plants with high

levels of soluble, organic or slow-release fertilizers. Unfortunately,

very high levels produce root/shoot ratios of less than one, and result

in a plant with a large top, foliage or long vines and a small root system.








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'"Under -condition of high humidity-and frequent -atering -such..plants .will

become attractive .and_ appear-to be. of high quality. However.,.when these.

.plants-are placed under low humidities of most building.interiors,...many

older lower. leaves will become yellow and drop. This leaf drop will.occur

* .-even though soil moisture .is...satisfactory, because inadequate root systems

cannot maintain proper moisture levels within plant tissue. Therefore,

the most satisfactory nutritional level for the growers profit margin does

not always produce the best quality plant for the consumer. On the other

hand, consumers are generally not willing to pay the additional price of

small plants with proper root/shoot ratios.


Quality

The appearance of a plant is an important index of its quality.

Research at the Agricultural Research Center at Apopka and the University

of Florida has shown that medium to high levels of nitrogen and potassium

are necessary for proper color and leaf size. At the same time, other

important major and minor elements must not be neglected or "Quality" will

be lost because of small leaves, chlorosis or necrosis. Generally,

deficiencies of magnesium and iron are common and must be provided in the

fertilizer program. More recently, we have found fluoride toxicities in

Cordyline. These examples point out the possibility of reductions in plant

quality if positive nutritional programs are not established.


Longevity

Buyers and consumers would like foliage plants to last forever,

even in a dark corner, while producers know this isn't possible. The

main point,- however, is that foliage plants should be expected to provide









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consumers pleasure for three to six months, even under the poor growing

conditions. Light level is the most important requirement for longevity of

foliage, but it may also be severely influenced by soluble salt levels

within the growing medium. Under grower conditions where the soil medium

is moist at all times the soluble salts present from fertilizers and water

are generally not influencing quality adversely. However, once moved

into the market place or home, plants may be allowed to dry or wilt and

severe root damage from salt burn may result.

Calculation of soluble salts are based on the moisture percentage of

the growing medium. A salt level in moist soil of 2000 parts per million

(ppm), would not cause injury to most foliage plants, but if allowed to

wilt, or the soil to become dry the soluble salt level will double or

triple. These higher levels will severely damage root systems and can

predispose them to disease organisms or prevent absorption of nutrients

and water. Symptoms of injury from soluble salts on foliage plants in

the home may appear as marginal leaf ehlorosis or necrosis of newer leaves

and yellowing and dropping of older leaves.


Fertilizer regimes

Research to date indicates that there is no single source or level of

fertilizer that will do the best job under all situations. However, there

are average levels that will produce quality potted foliage plants provided

soils are properly prepared. Suggested materials and levels td use when

mixing potting soils are shown in Table 1.
P-











The main source of nitrogen and potassium as well as supplemental

phosphorus is most frequently soluble forms of fertilizer. However, slow

release materials such as Osmocote are also very desirable. The amounts

of chemical or slow-release fertilizers to use are listed in Tables 2 and

3, and vary for different plant types. Generally, philodendron, pothos

and dracaena require the listed amounts, while dieffenbachia, peperomia,

maranta and syngonium require about two-thirds that amount. If the soil

mixture is prepared according to Tables 1 and 3, fertilizer will not need

to be applied for 3 to 4 months.

Levels higher than those listed in Tables 2 and 3 should not be provided,

or injury from soluble salts may occur. As stated earlier, injury may not

appear in the growing range, but in the home when soils are allowed to become

dry.


Table 1. Nutritional amendments and amounts to add
to potting soils for foliage plants.


Material Amount/cu ydI Provides


Dolomite



Superphosphate


Perk or Fritted
Trace Elements


7 lb



4 lb


3 lb or
1 lb


, Based on soil mixtures containing 50
acid peat.


Calcium
Magnesium

Phosphorus
Sulphur
Calcium

All minor
elements
plus magnesium

to 75 percent


Ill









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Table 2. Liquid fertilizer program for potted foliage plants.


Soluble Lbs/1000 sq
materials Lbs/acre/mo.1'2 ft/mo. Remarks


May be mixed
Nitrogen (N) 167 3.8 from single
components or
Potassium (K20) 167 3.8 20-2-20 may
be used at the
rate of 835 Ib
Phosphorus (.P205) 16.7 0.40 /A/mo or 19 lb/
1000 sq ft/mo.


1Reduce rate by one-third when crops are grown in
more than six months.


the same pot for


2Based on soil mixtures containing 50 to 75 percent acid peat.


Table 3. Slow release fertilizer
foliage plants.


program for potted


Materials Lbs/cu yd1,2 Remarks


Osmocote Include in soil
(14-14-14) 10 mixture and delete
superphosphate
lasts 3 to 4 months

Osmocote 9 Ditto
(18-9-9)


1May be surface-applied after 3 to
may be switched to liquid if crop
4 months to mature.
2Based on soil mixtures containing
acid peat.


4 months, or program
requires more than

50 to 75 percent