Medically Reviewed by
Jason Crawford

Article Last Updated on December 31, 2022

Growing hemp has never been more accessible and more lucrative than now, but it’s still a fairly young industry, so even experienced hemp farmers are still figuring things out and learning new things. However, the hemp industry is very exciting at the moment, so no wonder everyone is doing their best to produce high-quality hemp biomass to sell.

Hemp farms are popping up everywhere at the moment and growers are doing their best to get the best out of their yields. But to do that, one of the most important elements is to know how many hemp plants per acre you should plant.

If you’re just starting out on this journey, this article may be helpful because it’s exactly what we talk about today.

On Hemp Production In the U.S.

After being illegal for almost a century ever since the 1971 Controlled Substances Act, industrial hemp (Cannabis Sativa L.) finally became legal on a federal level with the 2018 Farm Bill. With that, hemp cultivation, as well as buying and selling hemp became federally legal in the states.

As per the law, hemp plants should contain no more than 0.3% THC (tetrahydrocannabinol) to be legally cultivated. Hemp is naturally low in this cannabinoid and has high CBD (cannabidiol) content, but if the THC exceeds the limit, the hemp grower is required to destroy the hemp crops with elevated THC levels. 

Prospective hemp farmers should submit an application for a hemp growing license at the U.S. Department of Agriculture (USDA). However, apart from the license, each state has its own hemp growing program and requirements that mostly involve the location of the hemp farms and regulations of the THC levels present in hemp products.

Industrial Hemp Crops Are Grown for Different Purposes 

As you already know, hemp is a very versatile plant, and its stalks, seeds, flowers, and CBD content can be used to produce many different hemp products. Therefore, industrial hemp crops are grown for different purposes, and growers choose their hemp cultivars with the desired hemp product in mind.

Hemp can be grown for:

  • Fiber. Hemp fiber is very versatile and can be used for fabric, paper, building materials, etc, and it’s one of the more popular uses of hemp.
  • Grain. Hemp seeds are highly nutritious and their protein content is a competitor to soybeans, plus they contain all essential amino acids, so they can be used as food.
  • Oilseed. Similarly, hemp seeds can be cold-pressed to produce hemp oil, which is also highly nutritious.
  • Hemp flowers. Hemp flowers are fragrant and smokeable and their high CBD content makes them a great CBD product.
  • CBD hemp. Hemp is a major source of CBD and the majority of hemp farmers cultivate this plant for its CBD content, especially due to the high demand for CBD oil.
  • Hemp essential oil. Made from hemp flowers, it’s not a very popular product on its own, but it’s used in cosmetics, perfumes, and as a flavoring in candy and beverages.

How Many Hemp Plants Can You Plant Per Acre?

When you’re new to hemp farming, knowing how many acres of hemp you should plant is one of the most important things to make sure you optimize your gains. If you plant too few hemp plants per acre, you will be wasting space and your resources, and if you plant too many, your hemp crops won’t be able to thrive and reach their growth potential, so your yields will suffer.

The size of the majority of hemp farms is about one to ten acres, while the big-scale ones can be up to a thousand acres, and they’re mostly the ones that produce hemp flowers and hemp seed oil. So, before you plan out your hemp farm and purchase the seeds, you need to also think about which automation technology you’ll use per acre, as well as how many human resources you’ll need to be efficient because this will affect your costs.

How many hemp plants per acre you should plant largely depends on what you’re growing your crops for. In general, hemp grown for fiber needs less space to branch out because it’s more important to grow tall vertically, while hemp grown for CBD needs more space to develop bud sites and flowers because the flowers are the source of CBD.

Here’s how many plants you should plant per acre depending on what you’re cultivating your crops for:

  • CBD hemp: 1,000 to 1,600 plants per acre tended to as separate plants;
  • Grain and oilseed: around 400,000 to 650,000 plants per acre (or 10 to 15 plants per square foot);
  • Hemp fiber: around 1.31 million to 1.52 million plants per acre (or 30 to 35 plants per square foot);

Spacing the Hemp Plants

Hemp is a plant that grows very tall very fast (up to 15 feet), and it can yield up to 10 tons of biomass per acre. For example, an acre of hemp can produce about 700 pounds of grain, which can give you 22 gallons of hemp oil, 530 pounds of hemp seed meal, and 1,300 pounds of hemp fiber. But, in order to maximize your yield, you need to be smart about spacing the plants correctly. 

If you’re growing hemp for its CBD content, your plants shouldn’t be crowded because it will restrict their growth and flowering, and consequently, their CBD production. When planting them, you need to take into account that in the first eight weeks of vegetative growth your plants will double in size, so they might seem too far apart at the beginning, but when they start branching out, it will make more sense.

On the other hand, hemp crops grown for fiber, grain, and oilseed need to be planted closer to limit their branching, so their stalks can grow tall, strong, and fibrous, and so that more seed heads can develop. Unlike with CBD hemp, the goal here is to plant more plants per acre so that you can utilize all that space to encourage the plants to grow tall and get more biomass.

Tips On Successful Hemp Farming

Hemp is known as a well-adaptable plant that’s more resistant to pests than others, but it doesn’t mean that it will thrive just anywhere and in all growing conditions. Let’s see how you can bring your A-game to the hemp field.

Choose the Right Type of Hemp Seeds

Choosing the right type of hemp seeds is half the work because it makes your job easier for you right from the start. If you have the finances for it, it’s best to start growing from clones. It’s a more expensive option, but it’s the one that produces the most stable results since you’ll get female plants right from the start and skip germination, which saves a lot of time, plus there’s no risk of pollination. 

Feminized seeds are the next best option. Though they guarantee that 99% of the time all plants will be female, you’ll still need to double-check their gender because even one male plant can cause pollination and reduced CBD content.

Planting regular seeds is not a typical practice for growing hemp and is generally not recommended because of the uncertainty and the effort. Hemp is cultivated on big scales and when you plant regular seeds it’s wasteful and time-consuming to search for male plants to remove when you can have a whole hemp field of just female plants.

Choose the Soil Type and Test the pH Before Planting

The soil you plant your hemp crops in will play a huge role in your hemp cultivation. Soil is the home of your crops, it provides the nutrients for survival and support for the root system, so you have to make sure you’re working with the best soil you can find. 

Hemp thrives in loose, well-drained soils that are fertile and rich in organic matter, with a pH between 6.0 and 7.5. Like beans and onions, it doesn’t like soils with a high pH and salinity. It’s also best to avoid wet soils or else their growth will be stunted, while clay soils can cause tillage issues and excess wetness.

Pick the Right Hemp Cultivar for Your Climate

Industrial hemp is a very adaptable plant, but there are also many different cultivars and some might do better in certain climates than others. Therefore, it’s best to choose your hemp crops depending on where you live to ensure that the risk of mold and plant diseases is kept at a minimum.

Test the THC Levels of Your Hemp Plants

Since the legal limit for the THC levels in hemp plants is 0.3%, you should do your best to maintain this percentage. Hemp crops are subject to sampling and testing after the harvest to check if the THC levels of the plants comply with the law. Hemp farmers are required to submit samples of their hemp crops to state authorities, and if the samples exceed the THC limit, the crops will be destroyed. 

To avoid having your crops destroyed and your efforts going down the drain, make sure to test their THC levels early and frequently, because some hemp cultivars may perform differently depending on the environment, especially if it’s a type you haven’t cultivated before.

Maintain a Low-Stress Environment

A key element to maintaining high CBD and low THC levels is making sure your hemp plants thrive in a low-stress environment. That means that frequent temperature changes, excessive exposure to UV rays, or infrequent irrigation, for example, could propel them to produce more THC as a defense mechanism. 

Bottom Line – Depends On the Type of Hemp Product

After the federal legalization of hemp with the 2018 Farm Bill, the hemp industry has been blossoming beautifully, which results in the huge variety of hemp products we have on the market today. In order to cultivate hemp legally, hemp farmers need to apply for a license and they need to decide what type of hemp they’ll grow. CBD hemp is currently the most popular, but hemp fiber and grain can also be lucrative.

How many hemp plants per acre you should plant depends on what type of hemp you’re growing – CBD hemp needs more space, and therefore fewer plants per acre in comparison to hemp grown for fiber and seed production, which needs less space between plants, meaning more plants per acre.

A passionate advocate for the benefits of cannabis. Fraser Horton, who has a background in botany and a strong love of nature, has spent years researching how cannabis affects the body and mind. He established Leaf Nation in 2020, where he has devoted himself to educating people about the legalisation of marijuana and its safe and responsible use. Fraser is committed to highlighting cannabis’ potential for improving wellness and working to dispel the stigma associated with its use.


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