2014 Easter Lily Schedule

Easter 2014 falls on April 20th. This is a late Easter as on any given year the date of the holiday ranges from March 22 to April 25.

The timing of the Easter holiday is linked to certain astronomical events and therefore varies widely from year to year. The Easter date always falls on the first Sunday that follows the first full moon after the vernal equinox. The full moon in March of 2014 occurs just prior to the March 20th vernal equinox. Therefore Easter Sunday is pushed back to the first Sunday after the first full moon in April (on Tuesday April 15th).

Easter holidays that fall on extremely early or late dates each present a special set of problems for growers. On very early date holidays it can be a real challenge to complete the 23 week program on time, and often growers are forced to cut corners in the forcing schedule to bring the crop in on time. On late date holidays like we face in 2014, the lily schedule has more than enough time for growers to complete each step in the bulb-cooling and greenhouse forcing program without cutting corners. In fact most growers will be challenged to hold back development so that the lilies do not come in too soon.

Under ideal circumstances programming of the Easter lily crop begins 23 weeks before Easter to allow adequate time to fully cool and force the crop for maximum quality. This season, growers receiving bulb shipments in late-October will find that they have an extra two weeks or more in the production schedule.

Using the extra crop time
Here are a few options you can use to manage the extra time in the 2014 forcing schedule productively.

One opportunity occurs during the bulb cooling period. The lily bulbs need to accumulate six weeks (1,000 hours) of cooling at 40°F-45°F to be properly vernalized. Too much cooling (more than six weeks) hastens finishing time, and reduces both leaf number and bud count. You want to avoid over cooling since it will just make the lilies finish even quicker and with lower quality. However, you can prolong the cooling period without these adverse effects. Here’s how. Start cooling the bulbs at 40°F-45°F as normal. After four to five weeks of normal cooling, drop the temperature to freezing or slightly above (32°F-33°F). The near freezing temperatures suspend normal metabolism placing the bulbs in a near dormant state, during which additional vernalization won’t occur. The bulbs can be held at this temperature for two to four weeks if necessary. Once enough time has passed to put production back on the optimal 23 week schedule the temperature can be raised to 40°F-45°F for the remainder of the six-week vernalization period. A word of caution when using this technique, the temperature must be carefully monitored and controlled. A light freeze of 32°F won’t harm the bulbs but a hard freeze will.

A second opportunity to use the extra time coincides with initial bud set. You can lower the greenhouse air temperature following primary bud initiation from the normal 60°F-62oF (day and night) regime to 46°F for a period of one to two weeks before resuming normal bud initiation temperatures. The cooler temperature during this stage has the added benefits of both slowing the rate of crop development and increasing bud count.

Beginning with shoot emergence, maintain greenhouse air temperature at 60°F-62oF (day and night) until primary bud initiation begins. Once primary buds are set, lower the greenhouse temperature to 46°F to stimulate increased secondary bud formation. After a week or two of 46°F temperatures, raise the temperature back to 60°F-62°F until bud initiation is complete. Timing of the 46°F treatment is critical. It must start with primary bud initiation, which coincides with stem root initiation. The duration of the 46°F treatment will be dictated by how much extra time in the forcing schedule you are trying to use. If you start greenhouse forcing just one week ahead of schedule, the duration of the 46°F cool period should be limited to seven days. If you have two extra weeks the 46°F treatment can go for two weeks.
 

The best way to tell when bud initiation has started is to dissect some lily plants and examine them. This requires strong magnification to view the anatomical changes in the shoot tip. By comparison, stem roots are easy to view and bud initiation typically starts just as stem roots begin to emerge. It is important to determine when primary bud initiation occurs in order to achieve the desired effect on bud count. Flower bud initiation may be adversely affected or delayed by temperatures that are lowered before bud initiation starts. In contrast, temperatures lowered after bud initiation is complete will have no effect on bud count but will slow lily growth.

If you plan to lower the forcing temperature during this stage for the full 14 days, greenhouse forcing of case-cooled lilies needs to begin 19 weeks before Easter rather than the normal 17 weeks. For pot-cooled lilies, greenhouse forcing needs to begin 16 weeks before Easter rather than the normal 14 weeks. If you only plan to lower the forcing temperature for 7 days, start case-cooling on week 18 and greenhouse forcing on week 15.

The 2014 Easter lily schedule projects lilies for sale one week before Easter. However, most growers begin shipping lilies two weeks before Easter. Natural variation in maturity within a crop typically produces enough early blooming plants to meet this demand without changing the basic schedule. If you want to bring the bulk of his crop in earlier you will need to adjust each step in the production schedule back one week.

Controlling lily development
After bud initiation is complete, use temperature to control the rate of lily development for the duration of the greenhouse forcing schedule. This year growers will want to run cool temperatures (63°F-65°F) early in the season since outdoor temperatures will probably force lilies to develop very fast during the last month of the season.

Click the image above to see the full 2014 Easter Lily Schedule

Both the leaf unfolding rate and the rate of flower bud elongation can be increased or decreased with temperature. For example, at an average daily temperature (ADT) of 72°F the typical leaf unfolding rate is two leaves per day, but at an ADT of 63°F the rate decreases to 1½ leaves per day. Likewise, a lily will go from visible bud to bloom in 31 days at an ADT of 70°F, but it will take an additional week at an ADT of 60°F. If the temperature can be controlled within these limits, finishing can be delayed without sacrificing quality.

With naturally cooled lilies follow the controlled-temperature forcing (CTF) schedule, but remember the ability to control temperature during vernalization is limited and you may not be able to hold at near freezing temperatures to delay vernalization. However, if these temperatures occur naturally they need to be factored into the production schedule. Once vernalization is complete, reassess the schedule. If there is extra time, use temperature to increase bud count and to control the rate of crop development as previously described.

Finishing the crop
Plants that reach the puffy white bloom stage early can be held in a cooler (35°F-45°F) for up to two weeks. Growers with adequate cooler capacity may want to bring plants in early just to free up bench space for other spring crops. A Fascination or Fresco spray should be applied to lilies that are held in cool storage for seven days or more. Apply 100 parts per million over the top of the crop just before moving the plants into storage.

In addition to Fascination, EthylBloc can also be used to increase post-harvest flower life. EthylBloc works by inhibiting the damaging effects of ethylene, a naturally occurring plant hormone that greatly accelerates the onset of flower aging and death. Plants produce ethylene naturally but ethylene can also result from the incomplete combustion of fuels in a greenhouse, in storage, during shipping, or in the warehouse environment. The active ingredient in EthylBloc, 1-methylcyclopropene or 1-MCP, is released as a gas and therefore lilies must be treated in an enclosed environment. A sealed shipping container or truck, or sealed greenhouse can be used to treat plants. Flowers must be fully developed before treatment. To extend flower-life, treat lilies with EthylBloc just prior to harvest, or immediately after harvest, or just prior to shipping, or upon arrival from a supplier, or just prior to sale. Plants can be treated more than once without harm. Note: Repeat applications are recommended on species such as lily that bloom sequentially over time. EthylBloc should be part or your plan if you anticipate ethylene problems in cold storage, or if buds are fully opened before cold storage begins, or if plants were held in cold storage for more than one week. In all such cases an application before and after cold storage would be warranted.

When you plan your schedule think about the prevailing weather conditions you can anticipate in your region as well as the greenhouse control options at your disposal and the demands for greenhouse space you expect in April. Once under way, be sure to count leaves early and to monitor development often. This is important for managing your crop during the final 10-12 weeks of the schedule.
 

 
Notes & comments on the 2014 Easter Lily schedule

Insurance lighting: Insurance lighting will not be needed this season. Everyone should be able to complete the full 6-weeks (1000-hours) of bulb cooling before the designated greenhouse forcing date.

Fertigation: Start fertilizing using a 15-0-15 or comparable formulation when lilies emerge. If phosphorus was not added to the medium, 20-10-20 can be used on an alternating basis with a 15-0-15. Fertilizer rates should range from 200-400 ppm. Do not allow medium EC to exceed 3-3.5 mmho/cm based on a Saturated Media Extract. Stop fertilizing 1-week prior to sale and use clear watering prior to shipping to reduce salt levels and maximize keeping quality. Do not withhold water or fertilizer to slow development. Do not over water or root rot problems may occur.

Decrease Leaf Yellowing & Delay Flower Senescence: To prevent early-season leaf yellowing (7 to 10 days before visible bud) and mid-season leaf yellowing (7 to 10 days after visible bud) spray Fascination or Fresco at 10/10 ppm. Apply only to lower leaves & cover thoroughly. To prevent late-season leaf yellowing and post-harvest flower senescence, spray 100/100 ppm to thoroughly cover all foliage & buds. Apply when buds are 3-3½ inches long but not more than 14 days before shipping or cooling. Protects leaves from yellowing for up to 14 days. Avoid direct contact of spray to immature leaves during early- & mid-season applications or increased stem stretch will result.

Disease and pest control: Before planting, clean bulbs of debris removing any damaged scales, especially scales that show evidence of infection. Once potted, root rots associated with Rhizoctonia, Fusarium, and Pythium are a concern. Drench immediately with Banrot, Pageant, or Empress, broad-spectrum fungicides, or you can treat to control these diseases separately by selecting from the fungicides specifically registered for Rhizoctonia, Fusarium and Pythium control on lily. Materials registered for Rhizoctonia and/or Fusarium include 26GT, 26/36 and many generics such as Pageant Intrinsic and Contrast (Rhizoctonia), and Terraclor (Rhizoctonia). Materials registered for controlling Pythium include Alude, Banol, Subdue Maxx (beware of using mefenoxam exclusively because of widespread fungicide resistance issues with this active ingredient), Segway, and Truban. Check with manufacturers regarding compatibility when tank mixing fungicides. Fungicides may also need to be re-applied later in the crop, check labels for guidance. Preventative biological fungicides (RootShield, CEASE, Actinovate, Mycostop or Companion) may also be applied at planting for disease suppression and to enhance root growth. Check with company or product labels information on time intervals between application of biological fungicides and traditional fungicides.

Aphids, fungus gnats and bulb mites are a major concern. Many chemicals are listed for aphid control, including: Safari, Flagship, Tristar, Marathon and many generics, DuraGuard, Enstar AQ, Suffoil X, Insecticidal Soap, Kontos, Endeavor and Aria. Fungus gnats can be controlled with some of these same chemicals as well as Citation, Distance, Adept, Pylon, insect parasitic nematodes (Nemasys, NemaShield, Scanmask, Entonem) and Gnatrol. Bulb mites, Rhizoglyphus robini, represent one of the more troublesome insect pests on lilies and effective management requires an integrated approach. Bulb mites are considered a secondary pest and are commonly associated with decay caused by fungus gnat damage and soil-borne fungal pathogens. To best manage this problem, sort out diseased and damaged bulbs before planting, handle bulbs gently and monitor and control fungus gnats. The soil dwelling predatory mite, Hypoaspis aculeifer, may help suppress bulb mites.

Note: Registration of pesticides varies by state so consult and follow labels for registered uses. To avoid any potential phytotoxicity or residue problems, spot test first before widespread use. No discrimination is intended for any products not listed.

Controlling Lily Height: Use A-Rest, Chlormequat E-Pro, Concise, Cycocel or Sumagic as needed when shoots are 3-5” tall. Split applications provide the best results. You can apply any of the PGRs at ½ to ¼ the normal rate (or even less) and use multiple applications as needed. Reduce the concentrations of Sumagic used when combined with DIF. Use DIF, or cool morning DIP, to control lily height. Equal day/night temperatures, high night/low day temperatures or a cool morning temperature dip will produce a DIF effect and keep lilies short. Monitor lily height regularly during forcing. If height exceeds the target size, run negative DIF or low concentration PGRs to slow stem elongation. If height is less than the target size, run positive DIF or apply Fascination or Fresco to increase stem elongation.