King’s AgriSeeds research in hemp cultivation has shown that fall planted cover crops can have positive, neutral, or even negative influence on hemp. Ideally, cover crops conserve soil and enhance soil health. Tim Fritz, President of King’s AgriSeeds in Lancaster, Pennsylvania, has coined the term Forecrop, a cover crop with an extra bonus. A forecrop is designed to significantly boost the economic crop that follows.
Take cereal rye, for example. It is the “go to” cover crop with plenty of attributes. It suppresses weeds, builds soil microbes, is inexpensive with a wide fall planting window. In King’s research, cereal rye accomplished the soil conservation goals but helped the hemp crop only slightly or not at all compared to leaving the field fallow or unplanted. Consider King’s Soil Builder Plus, a tailored mixture of species that has similar qualities to rye plus it fixes nitrogen, penetrates compacted soil and improves the hemp crop.
These two photos, taken in early June within one variety, show that the choice of fall-planted cover crop greatly influenced hemp planted the following spring. Tim Fritz, President of King’s AgriSeeds, stood in a trial plot indicating the width of the cover crop strip. The variety of hemp is the same, planted 26 days earlier. Hemp that followed cereal rye (left photo) was ankle high, and the soil was visible. Hemp planted after King’s Soil Builder Plus (right photo) was vigorous and nearly knee-high. This early advantage paid off in the final yield. King’s Soil Builder Plus, a strong forecrop for hemp, delivered more value for hemp than cereal rye.
In 2022, King’s AgriSeeds further investigated the forecrop concept with hemp, the idea that some cover crops promote the economic crop much better than others. Some of the differences were evident within a few weeks. At 26 days after planting hemp, cereal rye functioned as a cover crop. Plants are smaller overall, about 9 inches tall with proportionate leaf development. By contrast, King’s Soil Builder Plus significantly stimulated early plant development to grow to about 18 inches. The dramatic difference in development was attributed to the cover crop planted the previous fall. For that reason, Soil Builder Plus functions as a forecrop for hemp.
One product will not improve all economic crops
Creating appropriate mixtures is not as simple as adding clover and radish to a small grain. King’s research shows that a combination of species with fibrous and tap root systems, plus a legume may not automatically increase hemp yield. Surprisingly, wheat as a component of a complex mixture held back hemp growth and reduced yield, even after tillage. Fall planting date, a field’s weed potential, and spring seedbed preparation also influence forecrop components.
A forecrop must be tailored for the economic crop through testing. To illustrate, King’s recommends distinctly different forecrops for corn and tobacco. Since they have similar nutrient demands as hemp, would these same forecrops promote hemp yield? Based on trial data, neither forecrop pushed hemp as much as expected. Other cover crops, including straight species and diverse mixtures, were more effective.
Improving hemp yield with forecrops requires planning and testing
By planning two years or more in advance, farmers can achieve soil conservation goals and grow better hemp. Especially in a young industry, it’s smart for growers to visit private and university trials. Incorporating some of the strong concepts can save commercial hemp producers time and money. Perhaps more important, farmers can avoid poor cultivation practices.