Easter 2016 falls on an early date, March 27th. Bringing a lily crop in on time will be a special challenge and some time-saving choices will need to be made along the way.
The ideal production schedule requires a full 23 weeks to complete. That means growers will need bulbs in-hand by October 18, 2015 to run a normal forcing program and bring the crop in for the start of the Easter sales season. That is unlikely to happen this year since bulbs typically are not available until late October at best. That means that growers will have to cut corners at certain points in the schedule to hit the early 2016 date. Early Easters also target early ship dates, typically the week of March 20th or one week before Easter Sunday. This means that growers will need to complete the entire greenhouse forcing program under winter season weather conditions that include low sun angles, cold night temperatures and short-day lengths for much of the crop. Such conditions make it more difficulty and more expensive to push the crop if you fall behind schedule.
Ideally pot-cooled bulbs (this includes naturally-cooled bulbs) are potted as soon as they arrive, preferably by week 23 on the schedule (Oct 18th) and then held at 60-62F for 3 weeks. The potted bulbs are then cooled for six weeks (40-45F) or until week 14, at which time they are moved to the greenhouse for forcing. During the initial three weeks (starting on week 23) roots develop and the shoot meristem matures. The physiological developments that take place during the initial 3 weeks at 60-62F improve cold perception during bulb cooling (vernalization) and allow bulbs time to mature which helps to produce more uniform shoot development and flower response. However, this is the first place to cut if circumstances force a late start on the 23-week forcing schedule. If this is the case for you, cut the initial three weeks down to two or even one week. This will allow a little time for some root development to begin before cooling. That means you can jump in on the recommended schedule at week 22 or 21 (Oct.25th or Nov. 1st) and still be in pretty good shape the rest of the way. It is important to make sure you get at least one week of pre-chilling bulb development at 60-62F before starting vermalization.
Case-cooled bulbs also calls for 23 weeks from start to finish. Typically case-cooled bulbs are placed in the 40-45F cooler starting on week-23 or October 18th this year. After 6-weeks, bulbs are potted and moved to the forcing greenhouse (at 60-62F) beginning 17-weeks prior to Easter or Nov. 29, 2015. Shoots take longer to emerge with case-cooled bulbs, but should be up by week 14 (Dec. 20). The greenhouse-forcing phase of the schedule is the same as with the pot-cooled crop.
With case-cooled bulbs the critical dates are the onset of bulb vernalization (cooling at 40-45F) and the start of greenhouse forcing. If you cool your own bulbs, you’ll know how late you got started. For example, if you do not receive your bulbs until November 1st you will already be two weeks behind schedule. Here’s what I recommend if you are two or more weeks behind at the onset. Cool-bulbs for at least 4 weeks then pot and begin forcing. As shoots emerge, immediately begin insurance lighting for up to two weeks. If you are still behind, you will have to make up for lost time during greenhouse forcing but after bud initiation is completed.
If you buy in case-cooled bulbs, it will be important to know exactly how much cooling they received. You want the bulbs on hand so that you can pot and beginning forcing by week 17 (Nov. 29th). If you know or suspect that the 6-weeks of cooling was incomplete, be safe and use insurance lighting. If the bulbs arrive after Nov. 29th, you will have to make up time during greenhouse forcing but after bud initiation.
Rich McAvoy, UConn Extension
Complete 2016 Easter Lily Schedule with comments and photos by Dr. Richard McAvoy, UConn Extension
