Group Title: CFREC-Apopka research report
Title: Effect of potassium and potting medium on growth of golden pothos
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Permanent Link: http://ufdc.ufl.edu/UF00065305/00001
 Material Information
Title: Effect of potassium and potting medium on growth of golden pothos
Series Title: CFREC-Apopka research report
Physical Description: 4 p. : ; 28 cm.
Language: English
Creator: Chase, A. R ( Ann Renee )
Poole, R. T ( Richard Turk )
Central Florida Research and Education Center--Apopka
Publisher: University of Florida, Central Florida Research and Education Center-Apopka
Place of Publication: Apopka FL
Publication Date: 1991
 Subjects
Subject: Plants, Ornamental -- Effect of potassium on -- Florida   ( lcsh )
Potting soils   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: A.R. Chase and R.T. Poole.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00065305
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 70068854

Full Text



Effect of potassium and potting medium on growth of golden pothos iL


L. K. Case d


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University of Florida, IFAS, University of Florida
Central Florida Research and Education Center Apopka
CFREC-Apopka Research Report, RH-91-14 ..

Pothos (Epipremnum aureum) are produced by cuttings from stock plants frequently
grown outside of Florida. When growers receive cases of these cuttings, they assume that if the
cuttings appear to be of high quality they will root rapidly and grow into a salable unit within
a standard period of time. Sometimes cuttings do not root and grow as expected due to diseases,
shipping conditions, or pesticide toxicity. It is not uncommon to find that none of these factors
can be identified as the cause of the problem. Previous work on nutrition of vining stock plants
led to the following study on potting media and potassium effects on development of golden
pothos stock plants and cuttings derived from them.

Methods

Rooted cuttings of golden pothos were obtained from commercial producers and
established in Vergro potting medium. After rooting was well underway, they were transplanted
to 6 inch standard plastic pots containing Vergro or a mixture of Canadian peat and pine bark
(1:1 by volume). Each potting medium was amended with dolomitic lime and Micromax at the
recommended rate. All plants received nitrogen (from NH4NO3) and phosphorous (from H3PO4)
in the irrigation water once a week. Potassium treatments were also added to the irrigation
water (from KC1) for those treatments receiving potassium. Treatments were set up in a


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and top-dressed with 6 g/pot of the slow-release fertilizer Osmocote 19:6:12. After 4 to 6 weeks
under an intermittent mist, top grade was recorded using the scale described above.

Results

The first cutting for Test 1 was made on 10 July about 4 weeks after the experiment was
initiated. Three weeks later, the number of new breaks showed that plants receiving potassium
had more breaks (Table 1). When plants were trimmed on 22 August, the number of vines
removed was lowest for those in the 1:1 potting medium without potassium. Vine weight was
best for the plants in the Vergro potting medium regardless of potassium treatment (Table 1).
Cuttings removed at this time were rated for top grade after four weeks and showed no
significant differences based on either the potting medium or potassium treatment. Vines were
again trimmed on 23 October and at this time the vine weight showed an interactive effect of
the potting medium and the potassium treatment with a dramatic growth reduction for the plants
in the 1:1 medium which were not receiving potassium. Cuttings were also rooted from these
vines and showed a similar trend in cutting grade at the 3 December rating (Table 1).

Results from the second test were similar although the damage incurred by the no
potassium treatment appeared more quickly than in the first test.

Plants in Test 2 were potted and fertilizer treatments started on 17 December 1990. The
first cutting date was on 13 February reflecting the relatively slower plant growth due to the
cooler temperatures (60 to 90F) and decreased light levels (about 1400 ft-c average) compared
to those of Test 1. In this case, the vine length was significantly affected by the potting medium
but not by potassium treatment (Table 2). Number of vines was unaffected by treatment at this
rating. Plants were trimmed again on 12 March, when both potting medium and potassium
treatment affected the fresh weight of vines, although no interaction occurred (Table 2).
Number of vines was again only affected by the potting medium. No cuttings were taken from
these plants, although top grade rated on 1 May showed a significant interaction between potting
medium and potassium treatments.

Conclusions

In all cases, the poorest quality plants and cuttings generated from these "stock plants"
were obtained when plants were potted in 1:1 potting medium and did not receive potassium.
Vergro potting medium contains a small boost of fertilizer (containing potassium as well as other
elements) which was not present in the 1:1 medium which we made from raw ingredients.
Differences in the top quality of the cuttings established from potassium deficient plants appeared
about 1 to 2 months before deficiencies appearedin the stock plants. Potassium deficiency in
pothos is characterized by shortened internodes, stunted leaves (1 inch in length or less), leaf
necrosis and finally plant death. In one test, the appearance of notable deficiency symptoms
took six months, while in the other they appeared in four months. Prior to development of these
symptoms, growth reduction appears with standard sized leaves and vine appearance. Pothos
appear to be able to survive for 3 or more months without anymore potassium than is present
















Vine weight Cutting
No. breaks No. vines (g) Cutting gradeb Vine weight grade
Treatment" 27 July 22 August 22 August 21 September 23 October 3 December
Vergro, no 11.7 8.7 132 4.7 216 3.9
potassium
Vergro, 12.9 9.6 137 4.7 266 4.0
potassium
1:1, no 11.3 8.1 104 4.0 79 2.3
potassium
1:1, 13.8 8.9 111 4.6 210 4.1
potassium
Significance'

Potting
medium (P) ns ns 0.0001 ns 0.0001 0.0002

Potassium (K) 0.021 0.026 ns ns 0.0001 0.0001
P x K ns ns ns ns 0.0001 0.0001

a 1:1 potting medium was composed of Canadian peat and pine bark in equal volumes.
b Cutting grade was rated on the following scale: 1 (dead), 2 (poor, unsalable), 3(moderate, salable), 4
(good, salable), and 5 (excellent, salable).
c Significance of the analysis of variance (F value) is given. Numbers less than 0.01 are considered highly
significant, those less than 0.05 significant, and others ns or not significant.


in Vergro without growth reductions. Current recommendations for potassium levels in pothos
may be higher than actually required by pothos for good growth; however, be especially careful
not to lower rates to levels which support adequate stock growth but decreased cutting quality.


Effect of potting medium and potassium on growth of Epipremnum aureum 'Golden Pothos'
(Test 1).


Table 1.







ble 2. Effect of potting medium and potassium on growth of Epipremnwn aureum 'Golden ]
(Test 2).
Vine length (in) No. vines Vine weight (g) No. vines Top grace
treatment" 13 February 13 February 12 March 12 March 1 May
ergro, no 49.0 3.1 130.9 5.2 4.7
)tassium
ergro, 55.5 3.5 161.7 4.8 4.9
)tassium
1, no 35.2 3.0 62.0 4.3 2.4
)tassium
1, 44.2 2.9 114.2 4.0 4.0
)tassium
gnificance'

batting 0.049 ns 0.0001 0.02 0.0001
.edium (P)
atassium (K) ns ns 0.001 ns 0.0001
x K ns ns ns ns 0.0001

1:1 potting medium was composed of Canadian peat and pine bark in equal volumes.
Top grade was rated on the following scale: 1 (dead), 2 (poor, unsalable), 3 (moderate, salable), 4
(good, salable), and 5 (excellent, salable).
Significance of the analysis of variance (F value) is given. Numbers less than 0.01 are considered
significant, those less than 0.05 significant, and others ns or not significant.





















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