Growing Hemp in Maryland

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A Guide to Growing Hemp in Maryland

Maryland is hot and humid in the summers and cold and wet in the winters. Maryland soil is comprised of clay, sand, or silt or a combination thereof depending on where you live. As it’s partly cloudy all year around here, many gardeners rely on greenhouses to help moderate the temperatures and the amount of light that crops get. 

Plant Hardiness Zone(s) 

According the USDA Plant Hardiness Map, Maryland has a number of different zones ranging from 5b to 8a. While hemp is suitable for most hardiness zones, it is advisable to check the zone in a specific location especially in the colder parts of the state.

Thermal Profile

Maryland has a North Temperate Thermal climate which results in cool to mild temperatures. However, temperatures have been known to reach as high as 100 degrees F in the summer. The mild to warm temperatures are suitable for hemp cultivation.

Length of Growing Season

Industrial hemp is best grown outdoors in late spring to ensure it is ready to harvest in September. It can, however, also be grown indoors. Seeds can be planted indoors for two to four weeks before being moved outdoors for transplant. 

The optimal growing season for hemp falls between May and August with planting beginning in early May and harvesting in late August. It takes about 110 days for a hemp plant to reach maturity. However, this is dependent on day length and the final phase of maturation will not take place until days are shorter than 12 hours. Harvesting is recommended 8 days after the hemp plant and flower heads have fully matured.

Average Annual Sunlight

Maryland receives an average of 208 days of sun every year – 34 hours of which occurs during the hemp growing season. It is essential to ensure that a hemp crop receives maximum sunshine throughout the season and day as the plants are heliotropic.

Average Annual Precipitation 

Maryland receives an average of 40.72 inches of rainfall per year most of which occurs in the summer months. This amount of precipitation should easily meet the requirements of a hemp plant which ranges from 10 inches or 12 inches during the growing season. Additional irrigation should not be required.

Surface Elevation

The lowest elevation is at sea level at the Atlantic Ocean with an average of 350 ft above sea level for the state. These elevations should not negatively impact hemp cultivation however, cooler temperatures at higher elevations may not be suitable for optimal growth.

Soil pH

Maryland has a soil pH between 6 and 7 which is slightly acidic and ideally suited for most types of plants and crops including hemp. However, soil testing is recommended in certain areas where the levels may be higher or lower than this ideal.

Soil Composition

There are predominantly three soil types in Maryland including clay, sandy and silty. Clay soils are not ideal for hemp crops as the compacted nature can prevent the full development of a long taproot resulting in smaller plants with lower yield. Sandy soils will require additional nutrients to be added in Maryland. Silty soils that are not compacted are better suited to hemp cultivation.

Notable Pests

Common pests in Maryland include bagworm, striped cucumber beetle, leafcutter bee and leaf miner. These pest can be problematic to a hemp crop however, close attention needs to be paid to the various aphid and mite species that can be especially detrimental to the flowering heads. Controlling insects on hemp with pesticides is not highly recommended and should be avoided once the crops have entered the flowering phase of growth. Mold and fungus are also problematic with excess moisture, high humidity or in wet conditions.

Obtaining A Hemp Grower’s License In Maryland

Under federal law, it is illegal to grow hemp anywhere in the United States without first obtaining a grower’s license from the appropriate regulatory body for the state in which the interested party intends to plant the crop. View our breakdown of the 2018 Farm Bill for more information on the legal status of hemp in Maryland, as well as a breakdown of the application process.

Program Name Program Type Resources
Maryland Research and Commercial Maryland Department of Agriculture Industrial Hemp