Preventing Plant Stretch
Friday, 31 March 2006 10:48
Cooler night temperatures combined with the warm sunny days often result in plant stretch. The greater the difference between day and night greenhouse temperatures, the more stretch you will see on your crops. Some growers may be only reducing the night temperatures, to save on energy costs, with the daytime temperatures increasing due to the bright sunny days.
Many growers successfully use an early morning temperature DIP to reduce plant stretch. They reduce the temperature 30 to 60 minutes before dawn and maintain this lower temperature for the first few hours of the day.
Bedding plants may also become too tall if they are started too soon, are spaced too close together, are shaded by hanging baskets grown above them, or are grown in greenhouses with low light levels (due to old plastic) combined with poor ventilation, especially during the day.
There are no growth regulators labeled for use on herbs or vegetable bedding plants. For more information see the fact sheet: Controlling plant height without chemicals
Growth regulators may be used on many different ornamental crops including bedding plants, herbaceous perennials, and many different ornamentals to help manage plant stretch. Many growers may use multiple applications of growth regulators at lower rates to manage plant height and stretch, as opposed to one application at higher rates.
Links for more information:
Growth Regulators for Bedding Plants
Section D Growth Regulators In New England Greenhouse Floriculture Guide
For Herbaceous Perennials and Plant Growth Regulators Go to PGR DATA in left column and Search Under Herbaceous Perennials
Michigan State University, Growth Retardant Efficacy Trials on Perennials
Leanne Pundt
