Growth of pothos cuttings affected by nitrogen fertilization of stock plants

Return to: MREC Home Page

Return to: MREC Research Index

University of Florida, IFAS
Central Florida Research and Education Center - Apopka
CFREC Apopka Research Report RH-91-12

R.T. Poole and A.R. Chase*

Published nitrogen (N) fertilization rates for production of good quality acclimatized Epipremnurn aureum (Golden Pothos) plants recommend 16 g/N ft²/yr, which is a moderate amount of nitrogen (3). The current light level recommendations for production of acclimatized golden pothos are 1500 to 3000 ft-c. Light and nitrogen rate recommendations for golden pothos stock plant production and maintenance, 3500 to 4500 ft-c and 14 g/N ft²/yr (2), respectively, were published based on research performed when most stock plants were still maintained in beds.

Production and maintenance of stock plants have changed since these recommendations were published, with most stock plants now grown in containers, where leaching of nutrients from the medium is more rapid and root systems smaller. Propagation studies (1) showed a drastic drop in golden pothos stock plant yield when shade levels were increased from 40 to 80%. Other research (4, 5) showed leaf color at various light levels was affected by N levels, with higher N levels needed to prevent N deficiency symptoms developing as the higher light levels were used.

Many environmental plant growers obtain cuttings from their foliage plants in the early to middle stages of production, thus eliminating the expense of stock plant maintenance. This pruning causes lateral buds to develop, thereby creating a fuller more attractive final product. The following experiments were conducted to better determine the optimum fertilization rate of golden pothos for the production of healthy cuttings and acclimatized container plants at a light level between 1500 and 2600 ft-c.

Materials and Methods

Experiment 1, a 4 x 4 factorial test with 10 replications, was initiated 4 October 1989. Rooted cuttings of golden pothos in 3 inch pots were transplanted into 6 inch standard plastic pots using Vergro Container Mix A without superphosphate (Verlite Co., Tampa, FL 33680), amended with 1 lb Micromax (Grace/Sierra Co., Milpitas, CA 95035) and 7 lbs dolomite/yd². Plants were grown in a greenhouse where temperatures ranged from 70 to 90°F and maximum light intensity was 1500 ft-c. Overhead irrigation was applied two times per week. Plants were fertilized once per week with a 50 ml solution (about 2 oz) of H₂O, NH₄NO₃ and KCl in various amounts according to treatment number. Nitrogen rates tested were 14, 28, 42 and 56 mg N/6 inch pot/week. Potassium application rates tested were 0 (no K applied), 9, 18 and 27 mg K/6 inch pot/week. The plants also received phosphorous at the rate of 7 mg P/6 inch pot/week from H₃PO₄.

Experiment 1 was terminated on 27 November 1989 and the total number of leaves, vines and bad leaves (dead and dying, or discolored foliage) per plant were recorded. Electrical conductivity (µmhos/cm) of the leachate collected from growing media was also determined on 27 November using the pour-through nutrient extraction method (6).

Experiment 2 tested 5 levels of nitrogen fertilization using 10 replications per treatment. Research began on 30 January 1990, when rooted golden pothos cuttings in 3 inch pots were planted into 6 inch standard plastic containers, utilizing the same growing medium and amendments as in experiment 1. Plants were grown in a greenhouse, where temperatures ranged from 70 to 90°F, and were irrigated two times per week. Light level was higher than in experiment 1, with plants receiving a maximum of 2600 ft-c. Plants were fertilized once per week with a 50 ml solution made up of H₂O, 21 mg K, 7 mg P and 14, 28, 42, 56 or 70 mg N according to treatment number.

Foliage of stock plants grown in experiment 2 was graded on 19 March 1990 on a scale of 1 = poor quality vines, not much good quality cutting material available, 3 = fair quality foliage, adequate cutting material and 5 = excellent quality vines, many good cuttings obtainable. Number of vines and leaves per plant was determined on 20 March 1990. Number of bad leaves per plant and level of chlorosis (using a scale of 1 = mostly chlorotic foliage, 3 = approximately half of foliage chlorotic, 5 = healthy foliage, no chlorosis) were recorded on 11 April 1990.

Foliage was cut back to the edges of the pots on 12 April 1990. Harvested vines were weighed and cut into single node units. Cuttings harvested on 12 April were rooted, 10 per 6 inch standard pot, using Vergro Container Mix A, on a bench receiving 1400 ft-c, where temperatures varied from 70 to 90°F. Osmocote 19-6-12 (Grace/Sierra Co., Milpitas, CA 95035) was surface applied to cuttings on 8 May 1990 at a rate of 6 g/6 inch pot. Cuttings were allowed to grow until 6 June 1990, when experiment 2 was terminated following a determination of the final cutting grade of the crop, based on a scale of 1 = poor growth, 3 = fair growth and 5 = excellent growth.

Results and Discussion

Results from plants grown under 1500 ft-c in experiment 1 show the number of leaves, vines and bad leaves per plant, as well as electrical conductivity of the leachate, increased as the level of nitrogen in the fertilizer solution increased. Plants treated with 56 mg N/6 inch pot/week, the highest rate tested, had more leaves, vines and bad leaves per plant and leachate from these pots had the highest electrical conductivity readings (Table 1). No difference was found for potassium treatment and results are not included in this report.

Results from experiment 2, with plants grown under 2600 ft-c, show best quality foliage was produced with 42 and 56 mg N/6 inch pot/week, although 28 and 70 mg/N 6 inch pot/week also produced good plants (Table 2). Foliage weight was greatest when plants received 70 mg N/6 inch pot/week. Number of bad leaves per plant increased as N rate increased but level of chlorosis, a symptom of N deficiency, decreased as the level of N fertilization rose. Best quality cuttings were obtained from plants fertilized with 70 mg N/6 inch pot/week, the highest N rate tested.

Results of these tests indicate the need for different N application rates for potted plant production and stock plants for cutting production. Producers relying on cuttings obtained from crops under production rather than on stock plants could apply a higher N rate to golden pothos in the early stages of production, then cut back on N application rate after cuttings have been harvested. Plants must receive the lower N rate for a significant part of the production process in order to be fully acclimatized. Manipulation of N rates could theoretically save producers the cost of stock plant maintenance.

*Professor, Plant Physiology and Professor, Plant Pathology, respectively. Central Florida Research and Education Center - Apopka, 2807 Binion Road, Apopka, FL 32703-8504.

Literature Cited

l. Conover, C.A. and R.T. Poole. 1972. Influence of shade and nutritional levels on growth and yield of Scindapsus aureus, Cordyline terminalis 'Baby Doll' and Dieffenbachia exotica. Proc. Trop. Reg. Amer. Soc. Hort. Sci. 16:277-281.

2. Conover, C.A. and R.T. Poole. 1976. Light and fertilizer recommendations for production of foliage stock plants and acclimatized potted plants. Univ. of Fla., IFAS, ARC-A Res. Rpt. RH-76-6.

3. Conover, C.A. and R.T. Poole. l990. Light and fertilizer recommendations for production of acclimatized potted foliage plants. Univ. of Fla., IFAS, CFREC-A Res. Rpt. RH-90-1.

4. Taylor, J.L., J.N. Joiner and R.D. Dickey. 1958. Preliminary report on the nitrogen light requirements of some commercially grown foliage plants. Proc. Fla. State Hort. Soc. 71:434-438.

5. Taylor, J.L., J.N. Joiner and R.D. Dickey. 1959. Nitrogen and light intensity requirements of some commercially grown foliage plants. Proc. Fla. State Hort. Soc. 72:373-375.

^ZElectrical conductivity (µmhos/cm) of the leachate from pots containing Epipremnum aureum fertilized with various levels of nitrogen. Leachate collected 27 November 1989.
^Yns, *, ** = Nonsignificant, significant at P = 0.05 and significant at P = 0.01, respectively.

^ZFoliage was graded on a scale of 1 = poor quality, 3 = fair quality and 5 = excellent quality foliage.
^YFoliage received a chlorosis grade determined using a scale of 1 = mostly chlorotic leaves, 3 = 50% of foliage had chlorotic areas, S = healthy leaves with no chlorotic areas.
^XPlants grown from cuttings were graded on 6 June 1990 based on a scale of 1 = poor quality, unsalable, 3 = fair quality, salable and S = excellent quality plant material.
^Wns, *, ** = Results nonsignificant, significant at P = 0.05 and P = 0.01, respectively.