Hemp Research

Can Waterhemp Competition Affect Hemp Growth?

Much is said about hemp being able to grow without herbicides or pesticides but is it really true?

Hemp is still a relatively new crop around the world. We need more research on the influence of weed competition on crop yield and quality.

Although hemp can be grown for seeds and fiber, most of it is aimed at producing flowers to then extract phytocannabinoids (mainly tetrahydrocannabinol (THC) and cannabidiol (CBD)) and terpenes to be used in therapeutic applications.

It’s very important to understand how external factors, like competing weeds, affect the chemical makeup of hemp because the 2018 Farm Bill established a maximum threshold of 0.3% of THC.

All hemp surpassing this amount of THC needs to be destroyed, which represents economical loss and potential legal repercussions.

We know that exploitative competition for resources can decrease the availability of water and nutrients, changing the growing conditions. We also know that some plants can sense their neighbors and adjust their metabolism and growth accordingly.

Another known phenomenon is that moderate drought and decreased nutrient availability can boost the THC content in hemp.

So, could competing weeds reduce water and nutrient availability and cause that same increase in THC? Some hemp producers believe it does but very little is known for sure.