Hops: Something else to grow hydroponically

Plant scientist Bill Bauerle has discovered that hops don’t need to go dormant in order to flower.

That may sound of little more than academic interest until you consider that it makes it possible to grow this crucial beermaking ingredient inside, and much more frequently than now.

The finding – the result of three years and 13 growth cycles of work at Colorado State University in the US – upends conventional wisdom and practice.  Hops are almost exclusively grown outdoors and harvested only once a year. 

That’s because it’s been the belief that the flowering bines, which require long periods of daylight, also need a low-temperature dormancy period – called vernalisation – when the buds reset under cold winter conditions in order to flower prolifically. 

However, using an impressive bank of pink-hued LED lights and precisely controlling the lighting periods, Bauerle was able to study the extent to which a dormancy period is indeed a necessary component for healthy hop flowers.

He cultivated and harvested four hop cycles in a year, using the LED lights to speed up production while also bathing his plants in assigned “photoperiods” – the daily duration of light that the plants harvest for energy.

Essentially, he fooled the plants into thinking it was “the middle of summer in British Columbia, or somewhere else with an appropriate day length”.

“The problem with hops is that if you don’t let them get big enough, they won’t flower,” Bauerle says.

“Up until 10 years ago, we didn’t have the technology as far as the LED lights and controlling the photoperiods like we do. Because people couldn’t get the plants to develop like they would outside, they assumed the lower flowering was because they lacked the vernalization period.”

Bauerle’s hydroponically grown hops already have made their way into several batches of local beers, and he says his work could be foundational for an indoor hop-growing industry, which could lead to even more new craft beers in what is already a booming market. 

Indoor hops also could make the most of biological pest controls contrasted with conventional field-grown plants, he says, which are susceptible to many soil-related pathogens and require heavy use of insecticides. 

“People would be shocked by how much field-grown hops are sprayed,” he adds.

And it’s not just hops. Bauerle has turned his attention to other hydroponically grown industrial crops, including hemp, which is in the same family as hops but has a fibrous, annual root system rather than a rhizome. 

The research is published in the journal Scientific Reports.