Flower bud induction is now stable and no further changes in induction levels should occur. The first wave of flower buds initiated growth in early December, but was a small number of the total available buds. This wave of buds has flowered. Overall, the induction level when these flower buds started their growth was low. In the Central Florida area, the current cool weather delayed this bloom a few days. Some trees in all districts have more flowers in this wave than is the general case for healthy trees. This wave will result in little fruit set on most trees.
The bloom date for the second wave of flower buds is still projected to be the end of February to the 1st week of March. A total of 800 to 1050 hours accumulated for this flowering wave depending on the citrus growing district. Continued cool weather may delay the full bloom date, but probably not more than a few days at most. Although more buds are starting to show swelling and bud break, there are still many buds on apparently suitable flowering shoots not showing any growth, although some are swelling. Based on the trees observed in Lake Alfred, it appears that there will be buds available for the projected third wave of flower opening as projected for mid-March. All areas have over 1100 hours below 68 degrees F. for that flowering wave.
In estimating the full bloom date remember that although a full bloom is projected for the majority of flowers at that stage, there is bud to bud variability and some flowers may open a week earlier or later than the average date. Also look at several trees within and between blocks. We have two Valencia blocks with very different proportions of flowering buds showing for the early March bloom. One block has many more buds pushing than the other, but neither has all of the available spring or summer shoots showing bud growth.
The main concern for this week is the projected cold weather on Saturday morning. If the projected low materializes on the Ridge and cold air drains to the low areas towards Arcadia and Immokalee, a large amount of the flush and flowers could be damaged. The National Weather Service is projecting 30 and 33 degrees F for the lows Saturday morning in Lakeland and Winter Haven, respectively. Everyone needs to keep a very close eye on the weather and evaluate multiple sources for low temperature projections.
(Questions?) – If you have any questions regarding flower bud induction and flower development, please contact me (albrigo@ufl.edu or phone 863-956-1151 ext 1207).
