Group Title: ARC-A research report - Agricultural Research Center-Apopka ; RH-81-17
Title: Leaching of potting media
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 Material Information
Title: Leaching of potting media
Series Title: ARC-A research report
Physical Description: 3, 1 leaves : ; 28 cm.
Language: English
Creator: 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: Potting soils   ( lcsh )
Soils -- Leaching -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Statement of Responsibility: Richard T. Poole.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00065944
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 70920046

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

Richard T. Poole FB i7 83
IFAS, University of Florida
Agricultural Research Center L.A..- Univ. o
ARC-A Research Report RH-81-17 "FS-Un .of Fi

To leach, according to Webster, is to dissolve out by the action of

a percolating liquid, or to subject to the action of percolating liquid

(for example, water) in order to separate soluble components.

Indoor foliage plants need water and nutrients to grow, BUT, does
the potting medium need to be leached for the plant to grow satisfactorily?

Does water need to be applied in sufficient quantities so that water and
nutrients pass from the potting medium with each irrigation? Many people

think, yes! The importance of leaching is taught in the classrooms and

S acknowledged by commercial producers of plants. Textbooks state, "very thor-
ough watering is necessary; there is comparatively little danger of too

liberal applications of water; enough water should be applied to result in

some drip through." But excessive amounts of water restrict soil

aeration and necessitate use of extra fertilizer.

Until recently water and fertilizer have been relatively inexpensive

items for the production of foliage plants, but cost of fertilizer has

increased greatly and water usage is now a critical problem. Water

shortages have appeared throughout the country, and certain areas of

Florida are facing crucial water shortages. There is also growing concern

regarding contamination of water supplies by run off from excess application

of fertilizers. Ideally, application of water and fertilizer would result

in no loss of water or fertilizer from plant containers while producing

excellent quality foliage plants. Thus, water use efficiency and application

should now be among the highest priorities in selecting irrigation systems.

Many experiments have been conducted to determine effects of

irrigation frequencies on plant growth, but the actual amount of water

needed to produce a marketable plant has been studied only recently.

Several studies have been conducted at the Agricultural Research Center-

Apopka, supported in part by a grant from the Foliage Education and

Research Foundation, Inc., to determine the interrelationship between

quantity of water and fertilizer applied, and the effect of this inter-

relationship with water usage and plant growth.

The first experiment showed the importance of applying the correct

amount of nutrition (Table 1). As fertilizer levels increased, efficiency

of water usage and top dry weight decreased. Examination of soluble salts

levels mhoss x 10-5) revealed the damaging effect of fertilizer applied.

As the soluble salts increased because of the increase in fertilizer

rate, root damage occurred and less water was utilized and top growth was


A second experiment (Table 2) showed an interesting relationship

between rate of fertilizer and volume of water applied. The high level

of fertilizer produced poor growth, while the low fertilizer level

produced good growth with top weight increasing as volume of water in-

creased, but root grade decreased as volume of water increased. Again,

soluble salts reflected the rate of fertilizer and water applied.

Other experiments have been conducted comparing plants grown in

pots with no leaching to plants grown in pots with conventional leaching

(Table 3). Plants supplied with the recommended fertilizer rate and

grown in potting media with good aeration and cation exchange properties

will produce good quality foliage plants comparable to plants grown in

potting media that are leached.



Work at the Agricultural Research Center Apopka has shown that good

quality foliage plants can be grown with no leaching of water or fertilizer,

resulting in no waste of water or fertilizer and saving the foliage

producer time and money as well as eliminating addition of nutrients to

the ground water supply. However, recommended amounts of fertilizer should

be applied to a soil with good aeration and water holding capacity and

high cation exchange capacity.

Table 1. Water utilization and plant growth resulting from 3 levels
of N-P-K applied with each irrigation.

Water utilized Top dry mhos x 10-5
Concentration (%) wt (g)
ppm N-P-K

Brassaia actinophylla
250-110-200 88 24 185
500-220-400 63 19 475
750-330-600 50 15 515
Peperomia obtusifolia
250-110-200 70 12 158
500-220-400 61 11 510
750-330-600 45 9 680
Chamaedorea elegans
250-110-200. 52 8 225
500-220-400 49 7 550
750-330-600 52 6 730

Table 2. Interrelationship of volume of water applied and fertilizer rate
on water usage and plant growth of Peperomia obtusifolia and soluble
salts of final leachate.

Cone (ppm) Vol (ml) Top fresh Root
200-90-170 water weight grade mhos
N-P-K applied (g) (5 = best) x 10-5

200-90-170 4140 139 3.7 170
800-360-680 4140 118 1.0 700
200-90-170 5040 156 3.3 165
800-360-680 5040 118 1.0 654
200-90-170 5940 165 2.8 172
200-360-680 5940 116 1.0 621

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