Young plants of Spathiphyllum are available primarily from tissue culture while a few cultivars are available from seed. The propagation of Spathiphyllum by tissue culture offers the grower the advantage of selected named varieties, improved crop uniformity and year round availability. Since this crop is backed by extensive breeding programs, commercial growers and consumers can expect a consistent supply of new cultivars.
Spathiphyllum produced from seed has, until recently, lost volume to tissue culture production. Previously, seed production, although economical, tended to lack the quality and uniformity demanded by today’s growers. Recently, large scale production of seed crops has gained popularity due to controlled seed production backed by excellent production and marketing systems.
Spathiphyllums require a potting mix with good drainage and water holding capacity. Generally a 1:1:1 ratio of peat, perlite, bark is a common potting mix for the southern United States, while course peat moss is common in Europe. Maintain pH at 5.8 to 6.5.
N-P-K ratio of 3:1:2 applied as a slow release or liquid feed produces high quality plants. Slow release dry fertilizers, constant feed liquid fertilization or combinations of both are equally effective methods of applying nutrients. Many growers incorporate slow release fertilizer in the potting mix supplementing later with liquid or additional dry applications. Additionally, many growers use a weekly foliar nutrient spray of 1 lb. Urea + 1 lb. Potassium Nitrate + 1 lb. Magnesium Nitrate per 100 gallons. A soluble source of trace elements can also be added to the above mix.
Watch for the following nutritional deficiency symptoms: Magnesium (Mg) deficiency, a problem with some cultivars, appears as golden-yellow margins on lower leaves. Prevention of Mg deficiency via supplemental Mg is much more effective than trying to reverse an Mg deficiency. Iron (Fe) and Manganese (Mn) deficiencies exhibited as reduced growth rates and chlorotic leaves can occur during winter months when the soil temperature is below 65°F (18C). Sulfur (S) deficiency, exhibited as overall chlorosis of foliage, is sometimes seen when using highly refined, low sulfur fertilizers. Boron (B) deficiency may be a cause of longitudinal ribbing of the leaves, often seen on new growth.
Irrigation frequency should be designed to keep the soil medium evenly moist during all phases of the crop cycle. Spathiphyllums easily tolerate overhead irrigation and do exceptionally well with drip. Spathiphyllums do not tolerate saturated soil conditions for extended periods of time. Various diseases can easily infect over-watered Spathiphyllum causing wilted or collapsed leaves, necrosis along leaf margins and extensive root damage.
Production light intensities are somewhat cultivar dependent although a range of 800 f.c. to 2500 f.c. (9 – 27 klux) is commonly used. Plants grown in the lower foot-candle range tend to have longer petioles, reduced branching, a softer appearance and darker green color (pending nutrition). Under higher light intensities, the plants tend to be more compact, exhibit more branching and are lighter in color. Plants grown under excessive light intensities exhibit curled, pale or chlorotic leaves. Plants grown at the extremes of the light intensity range may produce fewer flowers than those grown in the central range.
The optimum temperature range for Spathiphyllum is 68°F (20C) nights and up to 90°F (32C) days but will tolerate lows of 45°F (7C) and highs of 95°F (35C). Spathiphyllum will not tolerate frost or even short term freezing temperatures without foliar damage and possible crop loss. Plants grown at temperatures above 95°F for extended periods can exhibit narrow leaves (strap leaf), loss of color, inhibited root development and reduced flower quantity and quality.
Spathiphyllum disease problems are directly related to the cultivar, climate, sanitation practices and cultural conditions. Plants grown in shade house structures with overhead irrigation, frequent rains and warm temperatures will be challenged by diseases more frequently than greenhouse grown plants. Common diseases such as aerial blight (Phytophthora), Myrothecium leaf spot and Pythium root rot can be effectively controlled or prevented culturally and chemically.
The most important disease problem that can affect every Spathiphyllum grower is a root rot caused by the soil borne fungus Cylindrocladium spathiphylli. This potent and highly infectious disease can cause rapid death of infected plants. The first symptoms are premature yellowing of lower leaves, followed by wilt and collapse of the entire plant at the crown. Occasionally one can see tell-tale necrotic black lesions at the base of the petiole of infected plants.
Terraguard 50WP, as a drench at 4 to 8 oz. per 100 gallons, has been the best chemical control until recently. Cleary 3336 50WP (8 to 32 oz. per 100 gal) and Medallion 50WP (1 to 4 oz. per 100 gal) also provide good control. However, good sanitation and cultural practices are essential for effective prevention.
Keep plants off the ground. Use clean pots. Time your watering so that foliage dries down before night. Keep benches, carts and trailers clean. Rogue out symptomatic plants at the end of the day when foliage is dry. Remove all infected material from the growing area. Avoid unnecessary traffic through the growing area. Disinfect growing areas between crops. Rapid fluctuations in moisture levels from wet to dry will make plants more susceptible to infection. Thus, overgrown plants are particularly susceptible.
Although iprodione (active ingredient in Chipco 26019) is no longer labeled for use on Spathiphyllum in the United States, growers should be aware that it causes extreme phytotoxicity on some varieties, especially ‘Sensation’. Even drift from applications on adjacent crops can have long term negative effects.
The insect pests of Spathiphyllum include aphids, caterpillars, mealy bugs, scales, thrips and white flies. Although this list seems substantial, insect pests are relatively minor problems for the grower since effective chemical controls are available. One exception should be noted here. Thrips have a voracious affinity for some of the larger leafed varieties. If left unchecked, the damage can become severe. In saran houses, we recommend a preventative maintenance program. It is important to spray to run-off because thrips accumulate in the leaf whorl and do their damage on emerging leaves.
Two growth regulators are commonly used on Spathiphyllum, Benzyladenine (BA) and Gibberellic acid (GA). BA is very effective at enhancing the branching and fullness of the plant and is generally used at the young plant (liner) stage. In addition to young plant treatments, some growers also apply BA shortly after young plants have been planted into a larger pot. Enhancing branching qualities and fullness are especially important to the small pot grower since shorter production time limits the impact of natural branching. BA can be applied as a spray or drench at 250 to 1000 ppm. BA treatments can inhibit root development if applied before roots are well established. The overall effect of a BA application is dependent on cultivar, BA concentration, stage of growth, application method and season.
GA is used extensively to force early or year round flowering of Spathiphyllum. With maturity, Spathiphyllum will naturally flower consistently in the spring and sporadically during the rest of the year. Since the market demands that Spathiphyllum be sold with flowers, growers use GA to gain year round sales advantage while also allowing programming crops for holidays, promotions or weekly orders. With GA, growers can also force early flowering to allow the production of smaller pot sizes. A standard treatment is a single foliar spray of 150-250 ppm GA, 8 to 15 weeks prior to sale. The spray concentration and time between treatment and flowering depend on cultivar and season of the year. Some cultivars produce good quality flowers after treatment while others do not.
Treated plants may exhibit narrowing of new leaves, stretching of the petioles and distorted flowers. Each grower needs to test GA in their facilities and with their cultivars. Growers also need to determine their market’s tolerance to some of the negative quality issues discussed above.
Prior to any large scale growth regulator treatment, growers should test small samples of each cultivar for phytotoxicity and growth regulator response. All growth regulators should be applied carefully and uniformly over the entire crop to ensure consistent results. Never apply growth regulators when plants are under stressful conditions.
The application of the above growth regulators may not be legal in all growing areas. Many growers have concerns that currently labeled growth regulators will eventually be eliminated or their application severely restricted. Spathiphyllum breeders are aware of these concerns and have recently introduced new cultivars that naturally exhibit improved branching and flowering habits.
Most growers use 10 to 14 week old young plants to line out larger pot sizes. Young plants from tissue culture (microcuttings) or seeds are usually grown and delivered to the finished grower in cell pack trays as small as 200+ to as large as 38 cells per tray. The most common tray size in Florida is 72 cells per tray. Spathiphyllum young plant growers specify how the plants were planted using terms such as “produced from clumps” or “plants per cell.” The term “clump” refers to a tissue culture produced cluster of plantlets held together by a callus tissue base while “plants per cell” refers to the number of individual microcuttings or seedlings planted per cell. Generally, tissue cultured “clumps” produce very full plants but can lack uniformity as a finished product. They are very useful for small pot (<6″) production where grow times and chemical flower induction does not allow time for natural branching or flowering. Young plants produced from individual microcuttings tend to have better uniformity, and given adequate time or growth regulator treatments most cultivars will produce full plants. The finished grower’s choice of the young plant cell size as well as the determination of plant material, i.e., clumps or number of plants per cell, is primarily dictated by the growers needs and/or market requirements.
Grow times are directly related to the cultivar, pot size, starter plant and cultural environment. Generally, a 3-4″ pot requires 3 to 5 months, 6″ pot 4 to 9 months, 8″ (20cm) pot 7 to 11 months, 10″ (25cm) pot 8 to 12 months and a 14″ (35cm) pot 12 to 20 months. Growers should consult with their young plant supplier for cultivar specific grow times.
* NUTRITIONAL REQUIREMENTS OF ‘SWEET PABLO’ PAT#10817
‘Sweet Pablo’ is the fastest growing cultivar of Spathiphyllum produced by Oglesby. As a result, its nutritional demands exceed those of other cultivars. Yellowing of ‘Sweet Pablo’ is usually not a single elemental deficiency, but rather an indication of the increased demands of this variety. This yellowing can be easily prevented or corrected.
If you are using a mix with pre-incorporated slow-release fertilizer, you will need to supplement with a top-dressing of a fast release 14-14-14, or other comparable blends. Use moderate levels at planting and at regular intervals throughout the crop time. Drenches of 20-20-20 or a similar fertilizer will keep the plant actively growing and green. If the plants become yellow, liquid foliar sprays will effectively green them up. Several applications may be required. Because of the very waxy cuticle on the upper surface of the leaves, foliar applications should be more effective when applied to the lower surfaces of the leaves.
If you are on a liquid program in a greenhouse, a constant feed of 20-20-20 at 200 ppm is ample. When alternating liquid feed with watering, increase the concentration to 250 ppm, being sure to leach well when watering.
** During our mild Florida winters, Spathiphyllum can be successfully grown under 63 to 73% saran. Some varieties even tolerate such high light levels during the summer months. Not so for Sensation. Bright light will ‘gray’ the black-green foliage and reduce the attractive interveinal ribbing, and in fact, will greatly reduce leaf expansion. A quality-grown ‘Sensation’ requires at least 80% shade in the summer. It has been observed that the best quality Sensations have been grown in shade levels as high as 90%. When grown under heavier shade, cultural management is easier too; i.e., water and fertilization. The less stress the better!
If the design of the greenhouse will permit, separate layers of saran to create an air space or buffer zone. This will enhance the quality of the light, and help cool the house. Keep in mind that as saran ages, light penetration increases; i.e., old 73% saran may in fact be closer to 50%
Please take these notes as a friendly reminder that quality results in repeat sales.
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This text is a recommendation only; it is not an endorsement of any products or acceptance of any liability as a result of usage.