Yields and Growth of Cuttings from Five Stock Plants Grown in Four Maximum Air Temperatures

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R.T. Poole, Ph.D.and C.A. Conover, Ph.D.*

University of Florida, IFAS
Central Florida Research and Education Center-Apopka
CFREC-Apopka Research Report RH-93-5

Tropical foliage plants need relatively high daytime air temperatures (70 to 90°F) to achieve optimum growth rates (1, 2, 3, 4). However, plant respiration increases as air temperatures rise, so that eventually plants are using more carbohydrates maintaining existing tissues than to initiate new growth (1). While temperatures as high as 104°F reportedly do not damage well-watered heart-leaf philodendrons, growth rates of this crop produced under different maximum air temperatures have not been compared (2).

In another test, Nephrolepis exaltata 'Bostoniensis' (Boston fern), Dieffenbachia maculata 'Perfection' ('Perfection' dieffenbachia) and Chamaedorea elegans (parlor palms) did not appear to be damaged when maximum air temperatures were allowed to reach 110°F and watered four times per week. However, growth rates were also not compared to plant growth under lower maximum air temperatures (5). Plants grown in such high temperatures may not look damaged but economic loss still occurs if growth rate is slower, increasing crop production time.

Maximum air temperature in areas where stock plants are maintained could influence cutting size and vigor. Since cuttings rely on stored carbohydrates until roots are generated, maximum air temperature in stock plant areas may influence vigor of propagation material. The following experiment measured stock plant yields and quality of propagation material from 5 foliage Plant species grown in 4 maximum air temperatures.

Research was initiated on May 21, 1990. Ready-for sale Aeschynanthus pulcher (lipstick vine), Aglaonema commutatum 'Fransher' ('Fransher' aglaonema), Epipremnum aureum (golden pothos) and Philodendron scandens oxyeardium (heart-leaf philodendron) grown in 6-inch pots and Dieffenbachia maculata 'Camille' ('Camille' dieffenbachia) in 8-inch pots were used as stock plants. All stock plants were grown in Vergro Container Mix A (Verlite Co., Tampa FL 33610).

Plants were placed in greenhouses under 1400 ft-c maximum light intensity where the minimum air temperature was 64°F. Maximum air temperature was 86, 90, 93 or 97°F and stock plants were watered 3 times per week. Containers were top-dressed with 10 g/pot 19-6-12 Osmocote (Grace/Sierra Co., Milpitas, CA 95035) on May 22 and again on July 16, 1990.

Cuttings were harvested at least three times over the five month test period. At harvest times, lipstick vine, golden pothos and heart-leaf philodendron stock plant vines were cut back to the rim of their 6-inch pots. On all harvest dates except the final one, four cuttings were obtained from each 'Fransher' aglaonema or 'Camille' dieffenbachia stock plant. On the final cutting date for each of these two species, all available propagation material from each plant was harvested. On harvest days, fresh weight of cutting material obtained from each plant was determined. Number of vines and nodes per vine were counted for lipstick vine, golden pothos and heart-leaf philodendron on those species' harvest dates. Also measured for each cutting group was length of shoots on heart-leaf philodendron cuttings after an average of twenty-seven days of propagation time.

After growth measurements were obtained, cuttings were propagated in 5-inch containers filled with Vergro Container Mix A. Lipstick vine, golden pothos and heart-leaf philodendron cuttings were stuck, five/5-inch pot, 'Fransher' aglaonema and 'Camille' dieffenbachia one/5-inch pot. Cuttings were placed under intermittent mist (activated for five seconds every thirty minutes, from 8:00 am until 6:00 pm daily), in a propagation greenhouse where maximum light intensity was 1000 ft-c and air temperatures ranged from 70 to 95°F.

Propagation and evaluation dates for cuttings are shown in Tables 1 through 5. Roots were graded based on a scale of 1 = no roots, 2 = little root growth, 3 = some healthy roots but no branching, 4 = healthy roots with some branching and 5 = several large branched healthy roots.

Results and Conclusion

Inconsistent results were obtained for weight of propagation material, number of vines and number of nodes harvested from lipstick vine stock plants during the three growth periods. Propagation material from plants in the low maximum air temperature weighed more than that from plants grown in the three higher temperatures for the last two growth periods measured (Table 1). However, root growth on cuttings from stock plants in 86°F maximum air temperature was more rapid only from cuttings harvested October 4, and number of vines per plant greatest on only on the July 26 harvest date.

Weight of cutting material produced by 'Fransher' aglaonema was not affected by maximum air temperatures (Table 2). When propagated cuttings from the three harvests were compared, no consistent effects on root growth were found for maximum air temperature in stock plant areas.

No clear growth trends can be seen in data obtained for the golden pothos stock plants and cuttings produced in this test (Table 3). Root grades from cuttings propagated on June 13 show cuttings from stock plants grown in 86°F had more roots, but cuttings with the highest root grade on August 21 came from stock plants grown in 97°F.

Heart-leaf philodendron and 'Camille' dieffenbachia stock plant growth and rooting response of cuttings were not affected by maximum air temperature maintained in stock plant areas. Tables 4 and 5 show averages of growth data from these two species collected in this experiment.

Results from this experiment indicate that maximum air temperatures, in the range tested, do not consistently affect stock plant yields or cutting root growth for the five foliage plant species tested. However, the expensive cooling growing structures may still be cost effective when air temperatures are below the ranges where plants show visible symptoms of damage. Although plants may not be damaged by temperatures higher than 97°F, volume of production would probably decrease due to a slow down in growth rate.

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*professor of Plant Physiology and Professor and Center Director (Retired 7/96), respectively, Central Florida Research and Education Center-Apopka, 2807 Binion Road, Apopka, 32703-8504.

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Literature Cited

1.Conover, C.A. 1969. Foliage stock plant production. Florida Foliage Grower 6(5): 1-9.

2.Conover, C.A., L.S. Osborne and A.R. Chase. 1984. Heart-leaf philodendron. Nurseryman's Digest 18(5):91-94.

3.Conover, C.A., R.T. Poole, R. J. Henny, R.A. Hamlen and A.R. Chase. 1981.Aglaonema production guide for commercial growers. Univ. of Fla. Orn. Hort. Com. Fact Sheet OHC-1. 5 PP.

4.Henny, R.J., A.R. Chase, C.A. Conover, R.T. Poole, R.A. Hamlen and L.S. Osborne.1984. dieffenbachia production guide. Univ. of Fla., Orn. Hort. Com. Fact Sheet OHC- 11. 6 pp.

5.Poole, R.T. and C.A. Conover. 1981. Influence of maximum air temperatures and irrigation frequencies during high temperature periods on growth of four foliage plants. HortScience 16(4):556-557.

^zCrop 1 fresh weight and number of vines harvested recorded on June 13, roots grades on July 17, 1990, after 34 days in propagation area.
^yCrop 2 fresh weight and number of vines harvested recorded on July 26, roots graded on August 23, after 28 days in propagation area.
^xCrop 3 fresh weight and number of vines harvested recorded on October 4, roots graded on November 14, after 41 days in propagation area.
^wRoot grades were based on a scale of 1 = no roots, 2 = little root growth, 3 = some healthy roots but no branching, 4 = healthy roots with some branching and 5 = several large branched healthy roots.
^vns, **; Results nonsignificant or significant at P = 0.01, respectively.

^zCrop 1 fresh weight of cuttings recorded on June 13, roots grades on July 24, 1990, after 41 days in propagation area.
^yCrop 2 fresh weight of cuttings recorded on July 26, roots graded on September 18, after 54 days in propagation area.
^xCrop 3 fresh weight of cuttings recorded on October 3, roots graded on November 26, after 54 days in propagation area.
^wRoot grades were based on a scale of 1 = no roots, 2 = little root growth, 3 = some healthy roots but no branching, 4 = healthy roots with some branching and 5 = several large branched healthy roots.
^vns, *, **; Results nonsignificant, significant at P = 0.05, or significant at P = 0.01, respectively.

^zCrop l fresh weight, number of nodes and number of vines harvested recorded on June 13, roots graded on July 10, 1330, after 27 days in propagation area.
^yCrop 2 fresh weight, number of nodes and number of vines harvested recorded on July 26, roots graded on August 21, after 26 days in propagation area.
^xCrop 3 fresh weight, number of nodes and number of vines harvested recorded on October 4, roots graded on November 1, after 28 days in propagation area.
^wRoot grades were based on a scale of 1 = no roots, 2 = little root growth, 3 = some healthy roots but no branching, 4 = healthy roots with some branching and 5 = several large branched healthy roots.
^vns, *, **; Results nonsignificant, significant at P = 0.05, or significant at P = 0.01, respectively.

^zRoot grades were based on a scale of 1 = no roots, 2 = little root growth, 3 = some healthy roots but no branching, 4 = healthy roots with some branching and 5 = several large branched healthy roots.
^yCrop 1 fresh weight, number of nodes and number of vines harvested recorded on June 13, roots graded and shoot length measured on July 10, 1990, after 27 days in propagation area.
^xCrop 2 fresh weight, number of nodes and number of vines harvested recorded on July 26, roots graded and shoot length measured on August 21, after 26 days in propagation area.
^wCrop 3 fresh weight, number of nodes and number of vines harvested recorded on October 4, roots graded and shoot length measured on November 1, after 28 days in propagation area.

^wRoot grades were based on a scale of 1 = no roots, 2 = little root growth, 3 = some healthy roots but no branching, 4 = healthy roots with some branching and 5 = several large branched healthy roots.
^yCrop 1 total cutting weight recorded on June 13, roots grades on July 3, 1990, after 20 days in propagation area.
^xCrop 2 total cutting weight recorded on July 20, roots graded on August 13, after 24 days in propagation area.
^wCrop 3 total cutting weight recorded on August 31, roots graded on September 21, after 21 days in propagation area.
^vCrop 4 total cutting weight recorded on October 3, roots graded on October 26, after 23 days in propagation area.