Ask Us: About Plant Growth Regulators
How can PGRs be used to reduce pruning and plant spacing of summer-planted perennials during the summer bulking-up period?
First, except for extremely vigorous crops, you probably will not want to use a liner dip prior to planting. The goal during the first growing season is to fill the pot and maximize root growth. Although PGRs have less effect on root growth than on shoot growth, you can still see some effects with higher rates or actual root applications. If you can use your irrigation system to apply a soil-active PGR, consider the watering-in or drench type application through the irrigation system when the plants are approaching the edge of the pot, but most perennial growers are using sprayers to apply their PGRs.
If you are using a soil-active PGR, consider using a sprench application (a high-volume spray) to give you more residual PGR activity with the drench effect of the higher volume. The goal here is to reduce shoot growth to limit the number of times you have to prune or space the crop. Once the crop is established, you can hit the plant with higher rates to control shoot growth. Plan on applying multiple applications. Be careful with your rates of application, especially as you change the volume applied. In a limited number of cases we have seen carryover effects of summer applications at high rates on growth the following spring. Some growers have reduced their pruning down to once a month with a weekly PGR spray and documented labor savings with the process.
I am trying to use PGR drench applications more, but they seem less effective on