Lisianthus Growing Information

Share |
 

Lisianthus :

 

Family: Gentianaceae

Genus: Eustoma

Species: grandiflorum

Common Names: Lisianthus, Prairie Gentian, Texan Bluebell

Seeds & Crop Information: approximately 700 – 1,000 seeds per gram.  Seeds are available as pelleted seeds.

 

History:

Although it is found in desert areas, it is not a true desert plant.  In its native habitat, Lisianthus is found growing along riverbeds and low areas where it always has access to fresh water.  In mid-summer, when the rain is less frequent, native Lisianthus plants push down deep roots into the soil to access fresh water.  Therefore, the root system is the key to producing Lisianthus.

In the 1970’s, Japanese seed breeding companies first produced open pollinated varieties and in 1982 the first F1 varieties were released.  Recently in 1996 the first 100% double variety was made available on the international market.

The popularity of Lisianthus as a cutflower worldwide has increased dramatically over the past decade.  The American, European and Japanese markets have been dominated with the single varieties, unlike Australia where consumers demand the double flowered varieties as they resemble rose blooms and their vase life is longer than roses.

 

The Growing Environment:

Lisianthus may be produced in open fields, in low-tech greenhouse that simply protect the plants from wind and rain or in climate-controlled greenhouses.  For best results, grow Lisianthus with a minimum temperature above 15°C.  Crop quality is greatest if the daytime high temperature is less than 25°C, although plants will tolerate much higher temperatures.

While open-field production is possible, most growers in moderate climates grow Lisianthus in open-sided greenhouses.  These greenhouses provide protection from rainstorms that can devastate a crop in flower.  Production in full sun can result in 60% shorter stems than the same varieties grown in greenhouses or in outdoor shade houses.

In regions that require heating, successful Lisianthus production requires both space heating and soil-surface heating.  Attempting to produce cut flower Lisianthus with only one of the two methods will mean a guaranteed crop failure.  Space heating heats the air around the crop and can be done with forced air heaters or finned heating pipes suspended above the crop.

Soil-surface heating requires a hot water boiler system.  The water should circulate over the surface of the beds in 2-cm tubes.  Water temperature should be no higher than 40°C.  Use a circulating pump that will provide a complete circuit of water in six minutes.  Under cooler environmental conditions, ground bed-heating systems are recommended from April through September.  Soil temperature should not drop below 15°C.

 

                                            

Soil Conditions:

The pH should be neutral to mildly acid (6.5 – 7: water extract).

Moderate to high levels of organic matter are required.  In Japan, for their high-density crops, a base fertilizer of an 8:3.5:6.5 compound fertilizer is applied at 5kg/100 square meters.  Good levels of phosphorous and potassium are recommended for flower size and stem strength.

                                                       

Bed Preparation:

Bed preparation prior to planting is the most important part of Lisianthus production.  First, test the oil.  Lisianthus grows best with a pH between 6.3 and 7.0, higher than many other cut flower crops.  Lisianthus also grows best with high calcium levels and adequate phosphorous.  Adjust the pH and add calcium and phosphorous prior to planting.  Generally, optimum pre-plant preparation includes spading and rototilling the ground beds at least once a year, prior to soil pasteurization.  Be sure bed preparation loosens any hardpan that forms below the planting bed.

Lisianthus is very susceptible to soil borne diseases.  New ground beds may not require treatment, but beds known to be infected should be treated to eliminate disease.  Growers report success with both steam sterilization and methyl bromide.  Biological control is also being tested.  Some growers from beds prior to treatment, while others wait until after pasteurization.  Disinfect all equipment used in bed preparation or planting to prevent reintroducing diseases.

Once the ground beds have been pasteurized, drip irrigation, soil heating and support netting should be arranged.  Highest quality stems are produced using two layers of support netting.  Generally, netting with 15cm x 15cm or 15cm x 20cm spacing is used in cut flower Lisianthus production.

 

Transplanting:

Transplant seedlings when they are young and actively growing, (around the 4th – 6th true leaf stage) in order to avoid stem rot, take care not to bury the plants too deep.  Setting the plugs a little “high” in the flower bed will help to guard against rhizoctonia.  To ensure a healthy start, maintain high relative humidity for 10 days after transplanting and do not let the soil dry out. 

 

                                                             

Watering:

Lisianthus irrigation requires careful attention.  Excessive irrigation increases plant susceptibility to soil-borne fungal pathogens.  On the other hand, drought stress can cause premature flower initiation resulting in short, weak stems.  Generally, the lower the light and temperature, the less water the plants require.

Most growers establish the crop with overhead irrigation, then switch to drip irrigation after roots are established in the beds.  Lisianthus also responds positively to overhead irrigation during periods of high heat and light.  Increasing humidity in the greenhouse with an early afternoon overhead irrigation can increase stem length in regions with high heat and light.  Avoid high humidity and overhead irrigation after buds have formed however, since botrytis can develop.

 

Lighting:

Lisianthus growth, crop time and flower quality are affected by light intensity and day length; response varies per variety.  Highest plant quality results from plants grown with the maximum amount of light.  In regions with low light intensity, supplemental high-intensity lighting may be necessary to produce a quality crop.

Lisianthus growers debate the effect of day length modification.  Those who have experimented with it feel that under low light conditions, supplemental lighting encourages stem elongation and flower initiation.  Growers report that solid set or cyclic lighting, day extension or night interruption have all resulted in high quality Lisianthus.  In general, growers have experienced good results with 16-hour day lengths.  Dutch growers use HD lighting, while growers in California have had success using one row of 150-watt incandescent lights spaced 3m apart for each 4.5m-wide greenhouse section.

 

Fertility:

Lisianthus grows best with fertility levels in the soil.  Some growers broadcast a 3-month slow-release fertilizer over the soil surface immediately after transplant.  Other growers begin liquid fertilization immediately following transplant.  In general, nitrogen should be predominantly in the nitrate form; potassium should be equal to nitrogen.  Feed with liquid fertilizer at 200 ppm N and K at every irrigation or every other irrigation.  Use supplemental calcium during production unless the soil has a high calcium content; calcium nitrate may be used as one component of the fertilizer solution to provide calcium.

 

Flowering:

During periods of high light and warm temperatures, a light shade on the greenhouse roof is recommended to avoid fading the flowers.  Stems are usually harvested when one or more flowers are open.  There is a longer period of time between the opening of the first and second flower than from the opening of the second and third flower.  Therefore, some growers remove the first flower and sell it for small bud vases and then harvest the stems when the second and third flowers open.

 

                               

Harvest:

Lisianthus are not known to be sensitive to ethylene.  However, pulsing with 10% sucrose for 24 hours after harvest increases vase life.  If possible, flowers should be harvested in the mornings, when it is cool.  Remove field heat by transferring harvested bunches to coolers to optimize postharvest life.  Do not ship flowers that have not had field heat removed.

 

Crop Timing:

Crop cycle from transplant to harvest is related to variety and environment.  In general, Lisianthus production requires up to 15 weeks under low light and temperatures, but can be as fast as 12 weeks with high light and optimum temperature.  While stem quality is highest at lower temperatures, crop time will be longer.

 

Variety Selection:

Varietal selections are divided between single- and double-flowering Lisianthus.  In general, the European and Japanese cut flower markets prefer single-flowering Lisianthus, while the United States market has tended towards double-flowering varieties.

Color preferences also differ between markets.  The most important color in Europe is dark blue, while in Japan the white blue rim bicolor dominates the market.

Other colors include rose-pink, white, purple, blue blush, pink blush, bicolor pink, yellow, ivory, and various, pastel shades.

 

                                                   

Insects:

Lisianthus are not particularly susceptible to insects, but can be attacked by aphids, leaf miner, lepidopterous larvae, thrips or whitefly.  Fungus gnat larvae can be a problem in seedling production.  A good scouting effort that includes walking all benches (especially the ends) can prevent surprises.  Initiating a spray program as soon as the problem occurs will usually eliminate the pest quickly; controlling a major outbreak can be quite difficult.

 

Diseases:

Claude Hope, the world-renowned plant breeder, said Lisianthus are susceptible to all known plant diseases, plus a few others.  As with insect control, it is imperative that growers scout all their Lisianthus beds regularly to find infections before they become severe.