Statewide Citrus Research and Extension

December 16, 2025

Flowering Bud Induction Advisory #2

Current Condition: Currently, most of the citrus-producing regions have moderate to high flower bud induction. Below is an extensive table of estimated induction hours accumulated around each FAWN station in the region. The next 10 days are predicted to be between 70s and high 50s, so it is expected that flower bud differentiation will start soon. If this weather continues, we anticipate seeing the first wave of bloom in mid-February in central Florida. However, significant cold weather at the end of December and January can slow down differentiation.

Season Forecast: This winter and spring (2026) are predicted to bring a weak La Niña, which means Florida will experience warmer-than-normal temperatures and lower-than-normal rainfall. Drought conditions are already evident in many citrus-growing areas and are likely to persist. This makes the season challenging: warm weather will encourage bud break, while drought stress will promote flower induction. Moreover, the intermittent cold spells we are seeing add further complexity by providing additional induction hours. Overall, the greater the fluctuations between warm and cold conditions, the more likely we are to see multiple waves of bloom.

We are in for warm and dry winter weather. Under these conditions, enough hours below 68 °F are likely to accumulate to induce an economic level of flower buds but intermediate warm periods during the winter can lead to multiple flower cohorts and a very prolonged bloom. On the positive side if dry weather prevails during the bloom period there could potentially be lower incidence of postbloom fruit drop.

We are currently working on updating the old DISC website, and we apologize for any inconvenience as it may be intermittently unavailable. In the meantime, a comprehensive list of all FAWN stations along with accumulated induction hours will be published every Monday until the website becomes fully accessible to everyone.

Contact Dr. Tripti Vashisth (tvashisth@ufl.edu) for any questions or concerns.

Flowering related management considerations for HLB-affected trees:

DO NOT drought stress HLB-affected trees even though drought stress promotes flower induction and suppress vegetative growth, you should not risk current crop due to additional drought stress. Drought stress can exacerbate fruit drop. Daily, lower volume irrigations to minimize fall drought stress is suggested, especially when the weather is warm.
Flowering enhancing fertilizer to increase the number of flowers are NOT suggested for severely HLB-affected trees as they are very less likely to benefit because of 2 reasons: (1) HLB-affected trees have more dead wood therefore, there are fewer buds available to become flower, interestingly a good branch of severe HLB trees has same flowering potential as mild HLB trees. So additional flowering promoting fertilizer is not needed. (2) High twig dieback and low fruitlet retention is the main concern with severe HLB trees in regards to fruit set. Only 2% of the total flowers turn into harvestable crop therefore, pushing trees to flower more is not advisable as that is likely to waste trees’ energy and resources in extra flowers.
Gibberellic acid sprays can be used to suppress early spring flowering but the timing of application is critical for GA to be effective. GA should be applied before warm temperatures (that is before differentiation begins). Previous research on HLB-affected trees in 2017-2018 (a La Niña winter) has shown that when GA applied in fall, early flowering was suppressed. Therefore, if you have a weak crop load and are forecasted to have warm spells, GA application can be considered to suppress off season flowering.

Given the current weather conditions and forecasts, applying GA sprays to suppress early flowering is advisable. Suppressing early bloom will help synchronize flowering and improve leaf production, resulting in a better source-to-sink ratio. A stronger canopy translates to better fruit production, especially on HLB-affected trees.

GA sprays also provide the added benefit of reducing pre-harvest fruit drop. However, if the fruit is intended for the fresh market, peel color can be a concern; a 2–4 month interval between the last spray and harvest is recommended. Research has consistently shown that GA applications do not affect Brix in ‘Valencia’ when this harvest interval is maintained. Do not apply GA on early and mid varieties if the crop is still present.

The window to apply for GA seems to be closing within the next 10 days. DO NOT apply GA after January 1st for flowering management.

*Date:15-Dec-2025*
*Location*	*Induction Hours*	*Level*
Alachua	1023	High
Apopka	822	Moderate to High
Arcadia	689	Moderate to High
Avalon	847	Moderate to High
Bapson Park	702	Moderate to High
Balm	787	Moderate to High
Belle Glade	521	Low to Moderate
Bristol	1135	High
Bronson	993	High
Brooksville South	909	High
Carrabelle	1090	High
Citra	980	High
Clweiston	582	Low to Moderate
Dade City	831	Moderate to High
DeFuniak Springs	1182	High
Dover	842	Moderate to High
Fort Lauderdale	265	Low
Fort Pierce	554	Low to Moderate
Hastings	964	High
Homestead	402	Low to Moderate
Immokalee	612	Moderate to High
Jay	1155	High
Joshua	747	Moderate to High
Kenansville	721	Moderate to High
Lake Alfred	788	Moderate to High
Lecanto	1001	High
Live Oak	1101	High
Macclenny	1062	High
Marianna	1122	High
Mayo	1096	High
Monticello	1184	High
North Port	714	Moderate to High
Ocklawaha	911	High
Okahumpka	858	Moderate to High
Okeechobee	710	Low to Moderate
Ona	784	Moderate to High
Palmdale	656	Moderate to High
Panama City	1132	High
Pierson	983	High
Poinciana	835	Moderate to High
Putnam Hall	1046	High
Quincy	1152	High
Sebring	559	Low to Moderate
St. Lucie West	646	Low to Moderate
Tiger Creek	797	Moderate to High
Umatilla	868	Moderate to High
Wellington	352	Low to Moderate
Yeehaw Junction	748	Moderate to High