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University of Florida, IFAS,
Central Florida Research and Education Center-Apopka
CFREC-Apopka Research Report RH-92-16
K. Steinkamp, A.R. Chase and R.T. Poole*
Epipremnum aureum, commonly known as pothos, is a climbing vine native to the Solomon Islands. Other common names for this plant are devil's ivy and hunter's robe. Juvenile leaves can grow to 12 inches long, are heartshaped and sometimes variegated, with yellow, white or silver green streaks depending on the cultivar. Adult leaves are large and waxy, often reaching 30 inches across, with perforations between veins. Plants in their natural habitat typically produce mature growth when they become well established; however, most cultivated plants produce only juvenile growth. Pothos have enjoyed long term popularity with consumers, probably because they tolerate indoor growing conditions and a wide range of soil moisture levels. For these reasons and because pothos are utilized in many different ways (totems, hanging baskets, dish gardens and various pot sizes from 3 to 10-inch), they will probably continue to be one of Florida's major foliage crops for many years. The following report is a summary of some articles concerning optimal propagation and production regimes for pothos species.
Stock Plants and Cuttings
Much of the pothos crop produced in central Florida was grown from cuttings obtained locally until the 1970's. Growers maintained stock plants under shadecloth in large beds (raised or in the ground), or purchased cuttings from local propagation nurseries. In 1969, Conover (5) reported that 50-60% shade (4000-5000 ft-c) and 60-65°F night and 90°F day temperatures were best conditions for pothos cutting production. Increasing slat shed shade levels from 40 to 80% decreased cutting weight and yields. Three fertilizer levels were tested, 500, 1000 or 1500 lbs N-P2O5-K2O/A/yr (.011, .022 or .034 lbs/ft2/yr) from a 1-1-1 source, but apparently fertilization level did not affect plant growth (11). Addition of dolomite and Perks® at rates of 7 lb/yd3 and 3 lb/yd3, respectively, to propagation beds did not effect rooting or growth of pothos cuttings grown in peat beds (10).
In 1972 researchers recommended 0.8 to 1.0 lbs P205, 1.7 to 2.0 lbs K2O/1000 ft2/month (.009 to .012 P2O5 and .02 to .024 K2O/ft2/yr) and light levels of 3000 to 4000 ft-c for optimum shade house production of pothos stock plants (9). Reduction of fertilizer rates by 30% in winter was advised for pothos in unheated propagation areas since plants utilized less fertilizer under winter conditions (9).
By 1987, much of pothos cutting production had moved to warmer tropical areas, mainly the Caribbean Basin. Cuttings from these areas spend a minimum of 2-4 days in shipment to Florida. Researchers at CFREC-Apopka examined the effects of shipping time and temperature on pothos cuttings (16). Cuttings propagated after storage for 4, 8 or 12 days produced healthy salable plants, although propagated cuttings grew slightly slower as storage time increased. Cuttings were not affected by storage temperatures of 50, 55, 60, or 65°F. In another test, cutting growth was also unaffected by ambient air temperatures of 65, 70, 75, 80 or 85°F for 24 hrs prior to propagation (16).
Reyes, Chase and Poole (20), produced 6-inch pots of golden pothos stock plants using 14, 42, 70 or 98 mg/N/6-inch pot/week from soluble liquid source, and maximum light levels of 2000 to 6000 ft-c, depending on time of year. During winter, best stock plants were produced at 3500 ft-c and 42 mg /N 6-inch pot/week. Best quality stock plants grown during summer were produced with 6000 ft-c maximum light and 70 mg N/6-inch pot/week. Cuttings harvested from summer-grown stock plants were allowed to root for 5 weeks, with maximum growth occurring on stock plants receiving 98 mg N/6-inch pot/week.
Poole and Chase found that N rate was more important than N source in golden pothos stock plant and cutting production (13). Nitrogen source only slightly affected stock plant growth and cutting quality. Stock plants receiving only nitrate nitrogen had fewer nodes per vine, although cuttings from these stock plants had slightly higher grades than cuttings from plants fertilized with ammonium nitrogen or ammonium nitrate. In contrast, N rate was very important for good stock plant growth and cutting production. Highest quality stock plants and cuttings grown in this test, conducted during the summer season, received 112.5 mg N/6-inch pot/week from a soluble liquid source.
In another series of tests, good quality pothos were produced with 4 g urea/6-inch pot (2). These plants were comparable to those grown in other tests using ammonium or nitrate N sources applied at rates of 42 to 56 mg/6-inch pot/week soluble fertilizer (12, 20). Nitrogen rate was more important for quality stock plant and cutting production than potassium (K) rate when plants were grown with a urea formaldehyde N source (2). Potassium in moderate amounts was essential for optimum growth. N:K ratios did not have a significant effect on stock plant growth but the combined amounts of N and K that plants received influenced growth and quality. Electrical conductivity of medium leachate and top quality grade were highly correlated. Additional research showed cutting quality was enhanced when K rates were increased from 0 to 6 g/6-inch pot, even though outward appearance of stock plants was not affected by K increases (3, 4).
Best quality cuttings are obtained from stock plants receiving a higher light intensity and fertilizer level than recommended for pot crop production. Light intensity should be 5000 ft-c in stock plant areas for best growth and quality of cuttings. Maintaining higher N levels in stock plants compared to pot crops seems to benefit pothos cutting growth in the early stages of propagation. Maintaining higher N levels in stock plants may ensure a good N source during early stages of cutting growth, even though these levels are not directly beneficial to the stock plants themselves. Results of recent tests show a fertilization range of about 70 to 100 mg N/6-inch pot/week, depending on air temperatures and irrigation levels produce best quality cuttings. A 3-1-2 analysis fertilizer will supply adequate P and K.
LIGHT AND FERTILIZER. Light level and fertilizer rate recommendations are lower for production of acclimatized golden pothos compared to those made for stock plants which never leave the production area (6, 8). Conover and Poole recommended 3000-4000 ft-c light intensity and 34-11-23 N-P2O5-K2O lbs/1000 ft2/yr (15.4 g N/ft2/yr) (8). The most current recommendations, published in 1990, are about 1500 to 3000 ft-c light intensity and 16 g N/ft2/yr (6). Pothos in 6-inch pots getting a 3-1-2 fertilizer such as 19-6-12 Osmocote (Grace-Sierra Co., Milpitas, CA 95035) should receive 4.0 g/pot/3 months. Pothos in 6-inch pots receiving a 20-20-20 soluble liquid fertilizer such as Peters (Grace/Sierra Co., Milpitas CA 95035) would get 1.3 g/pot/month.
In 1990, Poole and Conover used the pour-through method to determine leachate electrical conductivity levels associated with good quality, acclimatized 'Marble Queen'. Osmocote 19-6-12 3- month release rate fertilizer, surface applied at rates ranging from 7.2 to 24.0 g/6 inch pot/3 months, produced good quality plants with leachate electrical conductivity ranging from 1,200 to 5,600 µmhos/cm(15). A broad survey, measuring elemental composition of 26 species of good quality foliage plants, was conducted to determine range of elemental levels in tissue samples associated with good quality plant growth. Good quality golden pothos plants were found to have tissue levels of 2.5-3.5%-N, 0.2-0.35%-P, 3.0-4.5%-K, 1.0-1.5%-Ca, and 0.3-0.6%-Mg (19).
TEMPERATURE AND IRRIGATION. Fresh weight and plant grade of golden pothos were lower when plants were grown at 100°F or 105°F compared to 90°F or 95°F maximum air temperature (17). The recommended maximum air temperature for production of golden pothos is 90°F, which takes into account worker efficiency.
Bodnaruk, Mills andbIngram reported bottom heating at a constant 70F reduced crop time of golden pothos in 3-inch pots by 35 % in winter when maximum air temperature was maintained at 60°F (1). Crops were salable in 9 weeks compared to 14 weeks for pots without bottom heating. Shoot length and number of leaves were not affected by 45°F minimum air temperature with 70°F constant medium temperature, although foliage was chlorotic and plants unsalable. Plants grown at 50°F minimum air and 70°F constant medium temperatures were, however, of marketable quality.
In another experiment where minimum air temperatures were tested at spring and summertime levels (60, 65, 70, or 75°F), medium temperature did not influence plant growth or quality (14). Increasing air temperature from 60 to 75°F in winter increased growth and plant grade of golden pothos, but 70°F was recommended as the minimum production air temperature after economic factors (air heater use and fuel costs) were considered.
Poole and Conover also found that growth and grade of golden pothos greatly improved as night air temperature was increased from 60 to 70°F, but growth was not affected by temperatures of irrigation water (40, 50, 60 or 70°F) (18). No differences in growth were found in pothos watered for 16 weeks with deionized water, deep well water or sewage effluent although vine weight increased when plants were watered 4 compared to 2 times per week in the same test (7).
Best quality golden pothos are grown in 1500 to 3000 ft-c light intensity and fertilized at 16 g/N/ft2/yr. This means pothos in 6-inch pots getting a 3-1-2 fertilizer, such as 19-6-12 Osmocote, would get 4.0 g/pot/3 months. When a soluble liquid fertilizer such as Peters is used, pothos in 6-inch pots would get 1.3 g/pot/month. Since N source is not important to plant growth, fertilizer can be selected based on economic considerations. A production air temperature range of 70°F to 90°F is recommended for good plant growth and labor efficiency. Bottom heating is not important as long as air temperatures remain in this range.
Pothos production practices have changed in the last 20 years as shipping and storage technology improved. Many pothos cuttings are now produced off-shore, in tropical regions, where total production costs may be many times lower than production costs of a comparable crop grown in the U.S. Formerly, most producers maintained stock plants or purchased cuttings from local sources where growing regimes could be readily observed. Today cutting purchases can be an international affair, sometimes handled by a third party, the plant brokerage firm, where the main concern may be price. Foliage plant producers need to consider more than cost per unit when buying pothos cuttings. Before the purchase contract is signed, buyers should investigate supplier's stock plant production regimes, as well as environmental conditions under which cuttings are shipped and length of time cuttings will be in transit. This will maximize predictability of cutting performance after propagation.
*Technical Assistant, Professor of Plant Pathology and Professor of Plant Physiology, respectively, University of Florida, IFAS, CFREC-Apopka, 2807 Binion Road, Apopka, FL 32703-8504
1. Bodnaruk, W.H.,Jr., T.W. Mills, and D.L. Ingram. 1981. Response of four foliage plants to heated soil and reduced air temperatures. Proc. Fla. State Hort. Soc. 94: 104-107.
2. Chase, A.R. and R.T. Poole. 1992. Effect of urea nitrogen and potassium ratios on golden pothos stock plants and cuttings. Univ. of Fla., IFAS, CFREC-Apopka Res. Rpt. RH-92-6.
3. Chase, A.R. and R.T. Poole. 1991. Effect of potassium rate, temperature and light on growth of pothos. Univ. of Fla., IFAS, CFREC-Apopka Res. Rpt. RH-91-11.
4. Chase, A.R. and R.T. Poole. 1991. Effect of potassium and potting medium on growth of golden pothos. Univ. of Fla., IFAS, CFREC-Apopka Res. Rpt. RH-91-14
5. Conover, C.A. 1969. Foliage plant stock production. Fla. Fol. Grower 6(5): 1-9.
6. Conover, C.A. and R.T. Poole. 1990. Light and fertilizer recommendations for production of acclimatized potted foliage plants. Nursery Digest 24(10):34-36, 58-59.
7. Conover, C.A. and R.T. Poole. 1985. Use of sewage effluent as an irrigation source for foliage plants. Nurseryman's Digest 19(4):34, 36, 38 and 39.
8. Conover, C.A. and R.T. Poole. 1978. Selection of shade levels for foliage plant production as influenced by fertilizer and temperature. Fla. Nurseryman. 23(10):74-75.
9. Conover, C.A. and R.T. Poole. 1972. Fertilization practices for foliage plant stock production. Fla. Fol. Grower 9(3):4,5.
10. Conover, C.A. and R.T. Poole. 1972. Influence of propagation bed nutritional amendments on selected foliage plants. Fla. State Hort. Soc. 85:392-394.
11. 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 Deiffenbachia exotica. Proc. Trop. Reg. Amer. Soc. Hort. Sci. 16:222-281.
12. Poole, R.T. and A.R. Chase. 1991. Growth of pothos cuttings affected by nitrogen fertilization of stock plants. Univ. of Fla., IFAS, CFREC-Apopka Res. Rpt. RH-91-12.
13. Poole, R.T. and A.R. Chase. 1991. Influence of nitrogen source and rate on growth of Epipremnum aureum stock plants and quality of cuttings. Univ. of Fla., IFAS, CFREC-Apopka Res. Rpt.RH-90-22.
15. Poole, R.T. and C.A. Conover. 1990. Leachate electrical conductivity and pH for ten foliage plants. J. Environ. Hort. 8(4): 166-172.
16. Poole, R.T. and C.A. Conover. 1988. Storage of philodendron and pothos cuttings. Proc. Fla. State Hort. Soc. 101:313-315.
17. Poole, R.T. and C.A. Conover. 1987. Heat stress of foliage plants. Univ. of Fla., IFAS, CFREC-A Res. Rpt. RH-87-2.
18. Poole, R.T. and C.A. Conover. 1981. Growth response of foliage plants to night and water temperatures. HortScience 16(1):81-82.
19. Poole, R.T. and C.A. Conover. 1976. Chemical composition of good quality tropical foliage plants. Proc. Fla. State Hort. Soc. 89:307-308.
20. Reyes, T., A.R. Chase and R.T. Poole. 1990. Effect of nitrogen level and light intensity on growth of Epipremnum aureum. Proc. Fla. State Hort. Soc. 103: 176-178.