The following Agriculture & Natural Resources article originally printed in the 2019 Fall edition of the Oldham County Extension Newsletter.

Industrial Hemp Field Updates

Industrial hemp continues to be a crop of interest for both experienced and new producers. With increased production, we are also seeing the range of pests and field problems that can occur with this crop.

First, we have seen some issues with nutrient deficiencies. There are several reasons this can happen: 1) Not soil testing and not following soil test recommendations; 2) Not supplying enough fertilizer or not being consistent with fertilizer in fertigation/drip irrigation systems; and 3) Not checking soil pH and/or not correcting soil pH before planting. Soil pH affects plants’ ability to utilize existing nutrients and added fertilizer. Based on research information to date, the ideal soil pH for growing hemp is 6.4.

Agronomic information for growing hemp is still being closely researched and is very much a work in progress. Although industrial hemp was once a common crop in Kentucky, its production then was mainly for fiber. The majority of hemp in Kentucky now is being grown for cannabidiol (CBD) oil, and more research is needed to determine the best agronomic production practices.

Next, there are many pests that attack hemp. Some are more damaging than others. Insect pests like mites and aphids suck sap from the plant. Disease pests are numerous, and include Pythium root/crown rot, Rhizoctonia stem/root rot, and hemp leaf spot. These insects and diseases can impact growth and yield of hemp. Researchers work not only to determine the best agronomic practices, but also to identify the most significant pests. Recognizing these allows them to make recommendations to regulatory agencies about needed pesticides for hemp.

Producers interested in growing hemp should take time to research all the information that is available about the crop, including budget analysis and the permit application process. The following links contain information that should be reviewed.

An Introduction to Hemp and Hemp Agronomy
Required Permit Information
Economics of Hemp Production and Budget Spreadsheet
Labeled Pesticides
Kentucky Hemp Disease website
UK/KSU Hemp Videos

Written by Traci Missun, Oldham County Agriculture & Natural Resources Agent.