Tech Tip: Don’t let your Garden Mums bud too early and set back growth

Tech Tip: Don’t let your garden mums bud too early and set back growth

Mums may be short day (long night) flowering plants, but they can still flower under long days, especially during cold nights. 

Although flowering takes a bit longer, varieties that are Very Early to Mid natural season timing, as listed in the Fresh All Fall Guide, will initiate flower buds under 14.5 hour day lengths. This means you will need to manipulate day length to prevent premature flower bud initiation in April and May, and some areas, June.

Early varieties: Elena™ Gold, Dawn™ Yellow, Hannah™ Orange, Fiona™ Coral Orange, Hestia™ Hot Red.

Early varieties: Elena™ Gold, Dawn™ Yellow, Hannah™ Orange, Fiona™ Coral Orange, Hestia™ Hot Red.

Tech Tip

Very Early varieties: Brittany™ Yellow, Michelle™ Gold, Electra™ Amber, Keeley™ Orange, Aideen™ Red Fire.


Very Early and Early varieties (as shown above) will prematurely bud under long days. Pictures show plants grown under 14.5 hour day/9.5 hour night lengths at an average daily temperature of 66.7 °F with minimum night temp of 64 °F. 
Photos are 44 days after the start of long days. Gilroy, CA 2016.


How to Prevent Premature Budding in Garden Mums

Step 1  Use night interruption lighting

Use night interruption mum lighting during propagation and after transplant in April–June; year-round is ideal. A minimum of 10 foot candles of light is needed from 10 p.m. to 2 a.m. each night.

Step 2  Watch night temperatures

Be sure that night temperatures remain above 62 °F (ideally 65 °F) to prevent flower bud initiation that can occur from cold nights, even in the longest days of the year.

Step 3  Use a tray with larger cells

Propagate in larger cells to allow liners to stay inside with night temperature control longer before transplant. Try a 30-cell tray versus a 100-cell to allow liners to start branching and growth before transplant.

Step 4  Use a tray with larger cells

Start your garden mum crop later to allow for later transplant. Transplant and move garden mums outdoors in mid to late June, instead of late May and early June, when night temperatures remain above 62 °F. This results in larger finished plants with less crop time because there is no set back from premature bud set.

Pro Tip
If you can't control light or temperature, use Florel® applications.

Treat plants with Florel® plant growth regulator when you are not able to adjust the photoperiod with lighting and/or manage the night temperatures. Be sure to start treatments with Florel® before the plants are exposed to flower initiation conditions and before buds can be seen. Sprays at 500 ppm every 10 to 14 days are effective. Florel® cannot prevent bud initiation when pressure to flower from short day length and cold night temperatures are too strong.

Mum Grower Success Guide

Selection tips for blackcloth, spring, and the Fresh All Fall natural season programs.

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Mum Culture Guide

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Garden Mums At-A-Glance

Key selection, scheduling, and growing information for all garden mum varieties.

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2020 New Introductions

Learn about our newest garden mum varieties for the 2020 season.

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Mark Smith is the Technical Specialist for Syngenta Flowers North America.