It’s been a hot and dry start to the season and our hops are thirsty! Given our exceptionally dry start to the season and general lack of rainfall, higher irrigations rates may be needed this year to continue healthy bine growth and flower development. Irrigation allows you to apply water directly to your plants and can increase overall yields along with many other benefits. We strongly recommend that you irrigate, but how much water do your hop plants really need?
In general, hops in our region require 24-28 inches (651,696-760,312 gal/acre) of water per year and will require regular weekly irrigation supplementation to help combat moisture stress and continue healthy growth. In addition to the benefits on plant growth, regular watering can keep plants stress free and sometimes even reduce pest and insect pressure in your yard. Irrigation systems can help to alleviate some of the potential drought stress, but timing of water application is just as important as the amount of water hops are receiving. Hops require most of their water between training and flowering for optimal vegetative growth.
With variability in growing conditions and water loss through climatic conditions such as temperature, humidity, wind, and sun intensity there’s potential for significant water loss in any given growing season. We determined weekly irrigation requirements in each month of the growing season for one plant based on potential evapotranspiration (PET) rates in Burlington, VT (Table 1). To determine actual weekly irrigation amounts, weekly precipitation should be subtracted from the weekly irrigation.
Table 1: Weekly irrigation requirements for one plant by month
|Month||Gallons of water per week for one plant|
Given these weekly rates, it is often best to apply water in split applications 2-3 days per week, every other day if possible, and be mindful of rain events throughout the week. Higher amounts may be needed for establishing a new yard. While irrigating with these given rates, you’ll be shooting for a little over 1/2” per acre (~14,000 gal/ac) of water from irrigation each week during bine and flower growth. While we are only able to deliver 3000 gal/ac at a time on the farm due to the constraints of our well, some water is better than none in any case.