After decades of prohibition in the United States, hemp has finally become legal to grow again.
As this new and growing market is now opening up across the country, doing many wonders about the possibilities brought about by this diverse crop.
The global hemp industry has been in full gear while American farmers have had their hands tied by government regulation.
This inability to work hemp has left many gaps in understanding this fast-growing plant, including how to grow it.
What follows is a summary of things that you will want to know about if you are considering how to grow hemp properly.
A Note About What Hemp Is Not
When many Americans think about hemp, they imagine a plant used for drug consumption. Both plants originate from the same species (Cannabis sativa).
However, industrial hemp lacks the concentrations of component THC (tetrahydrocannabinol) that acts as a psychoactive element, that is responsible for producing a “high.”
Even outside of the United States, THC levels within industrial hemp markets have been regulated to lower producing species.
What is Industrial Hemp?
Over 10,000 years ago, hemp was first spun into usable fibers. Since that time, it has been made into many products for commercial use.
While some readers may be familiar with hemp rope, they are surprised to discover that hemp can be made into soft cloth used in a multitude of clothing.
Older uses include animal feed, insulation, medicine, and textiles. More modern applications at larger scale include:
- biofuels
- foods
- paints
- plastics
- water purification
- weed control
Hemp As A Crop
One fascinating fact with growing hemp is the rapid growth rate of the species.
Production can begin with plantings ranging from March through May, with mature plants ready to harvest within three or four months.
While the plant can be vulnerable to bacteria and fungus, the rarity of infected crops has made it a plant that growers have not had to use pesticides to yield a harvest.
In smaller settings, the plant has traditionally been harvested by hand. Mechanical harvesting, however, has become more prevalent in recent decades as more commercial uses have developed.
Planting Hemp
Even though hemp is a newer crop, many farmers in the States are still knowledgable on how to grow it. The lack of familiarity does not cause issues with its growing procedures.
This also includes
- When the seeds are planted.
- How the plant reacts to its environment
- Times where the crop can be cultivated. The process can begin in the warmer southern states as early as March
Northern regions (and mountainous countries) will see crops being started weeks later when other traditional plants are begun.
Planting should occur just after the last frost, so most states tend to offer windows of April or May as the earliest time for sowing.
The number of plants per acre depends upon the type being grown. For those who are looking to grow hemp for the CBD (Cannabidiol) market, will sow roughly 1,000 to 1,600 plants per acre.
These species are typically tended to as separate plants when growing. Those planting species used in more traditional applications, such as textiles, will place 100 plants in each square meter (400,000 plants per acre). They will be tended to more like a wheat crop than individual plants.
In the case of planting for more individualized care, hemp can be planted in rows like corn. It will provide the space needed for ease of access to the plants. It will be essential to remember that plants grown in rows may need more mechanical weed control.
The style of planting will open up more soil space and access to sunlight. With acreage that will be sown more like wheat, it can be drilled like other grain products.
It will allow for more plants per square meter. It will also limit the space and sunlight available for competing plants, such as weeds, to use.
The amount of seed used will vary, depending upon the species of plant being grown. While no established data is available for farming, many current producers are ranging between 25 and 35 pounds of seed for each acre sown.
Rowed layouts for individual access and tending might use less than this, and drilled plots may use this amount or even more.
As for planting depth, farmers in many states have found success with 1/2 to 3/4-inches producing excellent results.
Is Hemp Limited To Specific Growing Regions?
Fortunately, this versatile plant can be grown throughout most regions of the United States. Arid and desert conditions are an exception, like that found in large portions of states such as Arizona.
High mountains are another location that hemp will struggle in. It should be noted, though, that Colorado has led the way in hemp production since the prohibition was lifted.
It may have more to do with the state jumping into production after the 2014 Farmer’s Bill passed when compared to other parts of the country. However, long-term data will help to determine this better.
Outside of these extreme examples, hemp can be grown in most regions of the country.
Hemp Aeration
Water needs and the need for irrigation will depend upon the amount of moisture the area receives during the growing period.
Hemp requires anywhere from 20 to 30-inches of rainfall during the growing season to mature properly. Water is critical during the germination period as absorption rates increase up until flowering begins.
After this, absorption rates decrease noticeably with most species. An increase will then be noticed after flowering as seeds begin to form. Estimates place total water needed ranging from 80 to 130 gallons per kg of hemp produced.
Soil moisture levels do appear to correlate with plant requirements. It should be noted that lighter soils may require up to twice the water as a medium soil will need.
The USDA has noted that drought conditions will cause hemp plant maturity to speed up. This early maturity will be noticeable with stunted growth.
Conversely, heavy rainfalls and flooding can also destroy a crop. These scenarios may not be an issue in lighter soils, however.
Hemp Temperature Tolerances

Hemp can survive a variety of temperatures across the scale.
These plants will need a minimum of 34-degrees Fahrenheit to emerge. Ideally, sowing should be done until the temperatures reach 50-degrees.
Maximum growth temperatures would be at about 95-degrees, with a range of 65 to 77 degrees providing enough heat for rapid growth. At 61-degrees Fahrenheit, farmers have noted an increase reaching up to 2-inches a day.
Soil Considerations For Hemp
As with many industrial crops, it is crucial to have the soil tested before contemplating growing hemp.
A PH level ranging between 6.3 and 7.8 is needed, and it will need to contain at least 3.5-percent organic matter for successful harvests. Other critical chemical levels necessary for a hemp crop include:
- calcium 6000 ppm
- phosphorus 40 ppm
- potassium 250 ppm
- sulfur 5000 ppm
A deep root bed is vital for root growth, so it is advisable to plow at least eight inches in depth. Lower yields can result from less soil depth, especially less than six inches.
Many farmers prefer to do a deep plow in the fall so that the winter weather can help crumble the soil. Other considerations will include smoothing it finely as well as packing it.
These fall preparations can influence the following year’s yield and should be done annually. Quality soil is essential for good fiber yields from a stalk that ranges in the two and six-foot range. Stunted stalks below this will yield fewer fibers of poor quality.
Other Cultivation Considerations
Introducing hemp into a crop rotation can prove beneficial to other plants that are grown. Adding hemp has the potential to reduce disease and other soil pathogens.
As a fast grower, it is considered a natural weed control agent and will aid in overall soil structure. Hemp intercrops well with a variety of other crops such as:
- Brussels sprouts
- broccoli
- corn
- hops
- lupine
- mustard
- nettles
- turnips
Since regulations have been lifted, growers have noted that it does not work well with cress, pepperweed, spinach, tobacco, or vetch.
Diseases And Pests
To this point, the industry has not noted issues with diseases, insects, or other pests with hemp crops. It should be pointed out. However, that data is limited at this point.
While it is not common, there have been noted effects from bacterial leaf spot, gray and white mold, Pythium root rot, and blight. If a field has been infested in the past, then it is more likely these may occur with a hemp crop.
Of the insect problems noted to this point, it appears that the click beetle and spider mite stand out as damaging to hemp during growth as well as storage.
Other insects may also prove damaging to these crops, but data is lacking at this time. Standards for fighting infestations in hemp crops with pesticides and other treatments vary between growers.
While manure will satisfy a hemp crop’s needs, cottonseed appears to be an ideal fertilizer for the plant. Amounts can vary between 500 and 1,000 pounds per acre while plowing in the fall.
Some growers have noted that a previous year’s crop of cowpeas or soybeans will reduce the needed amount to 500 pounds. Many have also started a noted difference in crop yield with the use of chemical fertilizers, but data has yet to be collected to verify this with regularity.
Things To Consider Before Deciding To Grow Hemp Crops
Finally, we want to impart to you some critical considerations before entering into growing hemp. You will need to consider the fact that the market has not only leveled off, but it has also dropped a bit. It is all since the first couple of years that restrictions were lifted on growing hemp.
Lower prices and more extensive industrial operations will mean that you will not find financial success at the farmer’s market level of production. Also, regulations will vary from state to state and can add costs or lessen profits considerably.
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