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How to Grow Hemp: Avoiding the Pitfalls of Growing a New Crop

How to Grow Hemp: Avoiding the Pitfalls of Growing a New Crop

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Thank you for your interest in growing hemp! Please enjoy this webinar, presented by ClearSafe Labs and Harris Seeds. The article below is a scaled back version of what you can find in the webinar above. 

Why Are Hemp Genetics Important?

The genetics of your hemp is key to the overall quality of your crop. Bad genetics will make a great farmer look bad, and good genetics will make a bad farmer look amazing.

  • When thinking about genetics, you should keep in mind:
  • What products you are producing hemp for
  • The environment you are growing in, e.g. indoors vs greenhouse vs in a field
  • Your climate
  • Problems like disease, pests, mold, powdery mildew, etc.
  • Scale of production

What Different Hemp Products Can Be Produced?

When growing hemp, you are producing them for one of four hemp products. There is the hemp flower, the seed, the fiber, and the cannabinoids. Depending on which of the four you are producing them for, you will use a different farming method.

The Cannabinoids are really popular at the moment; labs are getting excited about the different uses there are. But aside from that, none of the four is vastly better than the other; it comes down to your preference for the process and what equipment you have available to you.

How Do You Choose a Genetic Partner?

When selecting a genetic partner, you need to consider an expert in the type of product you are producing and who has experience in your environment. If the hemp genetics are being produced for an arid, dry climate, then that is the climate that the hemp plants will thrive in. So, you need to know where these genetics are being produced first and foremost.

You also need to pay attention to the claims they are making and the guarantees they are offering. Do they guarantee high germination rates or a certain yield or quality? Do they provide customer service in case something goes wrong?

Why Is Scale Important?

The strategies and methods you use for growing hemp will vary greatly if you are growing one acre or ten acres, or hundreds of acres.

When determining the best scale for you and your crops, your first thought should be the demand from buyers and the capacity of processors in the area. There is no use growing ten acres of hemp if your processors cannot handle the capacity or if there are not enough buyers.

The type of product you are producing will also play a huge range in determining the scale of your production. Flowers and cannabinoids require a much more hands-on approach and care. Growers typically see a maximum of a thousand or sixteen hundred plants per acre.

The seed and fiber plants are a little more resilient, and the technology is there to automate most of the process. You could see up to four hundred thousand seeds per acre for seeds and fiber plants. All of the products require vastly different amounts of water, nutrients, and attention.

Most hemp farms are somewhere between one and ten acres in size. The big farms are up to a thousand acres and are producing hemp for flower and oil products. Hemp is a fairly new industry, so everyone is still learning and trying out what works best for them. There is no one formula yet.

Before you purchase your hemp seeds for a particular scale, you also need to account for how much you can use technology or mechanics to automate and how many human resources you need per acre. Do your research to find out how much time, resources, and cost each acre will take before you make your purchase.

How to Choose The Right Type of Hemp Seed

There are two kinds of hemp seed to choose from: feminized or mixed seeds. Each type has unique advantages and disadvantages that will influence your choice, dependent on your desired scale and end product.

Feminized Seeds

Feminized seeds mean that the plants produced will be mostly female plants. In general, only one out of a thousand plants will be male, so it takes the work out of sorting the plants.

Mixed Seeds

If you are growing hemp to produce seeds and you want to play around with the genetics, then mixed seeds may be more suitable. Mixed seeds will allow you to crossbreed the plants and hunt for phenotypes that give the plants certain traits.

Why Are Male Plants Undesirable?

Male plants can cause problems for hemp farmers growing flowers or oil products. This is because a male plant can pollinate the female plants, thereby reducing the oil content and the quality of the flowers.

It's important to teach your workers how to identify male plants and pull out when they find them.

Growing Best Practices for Hemp

Hemp seeds should be grown in the environment they are genetically engineered for.

One of the biggest mistakes hemp farmers often make is growing hemp on uneven land with divots or gullies. This produces pockets of moisture where some of the plants will be growing in conditions they were not made for. Where possible, try and grow hemp on a flat, even surface.

Similarly, you need to ensure your genetics match the climate for your area, especially in regards to the length of your season. If you choose a plant that has a long flowering time, but you have a short season, you are going to struggle to produce a good quality plant.

Also be aware of your capacity for growing and processing hemp. If you do not have sufficient dry storage for the hemp once you take it off the field, then you are wasting energy and money in growing excess plants. If you are growing for flowers or oils, you will need to provide supports for the flowers as the plant itself will not be able to support the genetically modified flowers. Use whatever support structures you have available. Many hemp farmers use trellising.

Use the genetics of your hemp plants to inform your decisions and preparations.

Starting the Seeds

Growers have the most success starting hemp seeds when they use heat mats or heated beds. It is so vital to keep the roots warm because that will promote a strong and healthy root system.

We use under table heating for the first three days; then put the seeds on a heated bench with a humidity dome for another three days. After that, we will add a little more air into the system by lifting the humidity dome a little so it can breathe. All in all, the plants get ten days of heating. Any fluctuations in temperature can shock the root system and prevent growth later on.

Hemp plants, especially clones really thrive in hot, humid environments, similar to a rainforest. We recommend combining a heating mat, humidity dome, and gentle misting to create an environment of 100% humidity for their seeds and clones.


When the plant is still young, you want to create a sterile environment for it to grow. This is where materials like jiffy plugs and rockwool will give you the best results. If you start the plant off in soil, it is likely to have bacteria present that will be harmful to the plant during its early growth.

Rockwool is fantastic during this early stage because it allows hemp farmers to use rock salts, nutrients, and hydroponics. The disadvantage of rockwool is that it is a one-time use kind of product. You cannot compost it or reuse it like soil.

After this young growth, you can either keep the plant in rockwool or you can choose to plant your hemp plants in soil. Soil is advantageous because it provides all the necessary nutrients for the plants, and you only need to water it. The soil does need to be healthy and enriched with nutrients to really nourish the plants. If the soil is not enriched enough, the flower will smell like hay and will be a substandard product. Really invest in good quality soil for your hemp crops to ensure a high-quality end product.


Light is another key factor in growing hemp. If you are growing your crops inside or in a greenhouse, you need to create a smart lighting system for your crops.

When you have your hemp plants indoors, you have complete control over the environment and can really optimize your crops by controlling the amount of light they receive.

  • 18-24 hours of light per day– when plants are young, they will stay in their vegetative state (growth state) as long as the light is present for at least 18 hours a day.
  • 12-16 hours of light per day – the minute the light drops into this zone, the plant will enter the flower cycle. It will only grow an additional quarter of its size and will focus most of its resources into producing flowers. Clear Safe Lab recommends using a super high-pressure sodium bulb during this stage to grow giant flowers.

You can now find horticultural lighting systems that incorporate a sunrise and sunset cycle. This will expose your plants to different light spectrums and wavelengths that would be present during sunrise and sunset. These lighting systems have been shown to really benefit the plants and new research is being undertaken to see what the optimum lighting is.

During the vegetative state, the plants prefer light in the blue spectrum, but in the flowering stage, the plants prefer red, pink, and purple light spectrums. There is a lot of research going on in the industry to figure out optimum lighting conditions and how best to deliver those to the plants.

A good way to tell if your plants are getting enough light is by looking at how compact they are. If your plants are not getting enough light, they will stretch out looking for light, and the distance between the nodes will increase. If your plants are getting enough light, they will be short and compact.

How to Control Pests in Hemp Crops

Hemp farmers are limited in what kinds of pesticides they can use on their crops. Choose the pest control substance that works best for your needs, budget, and the types of pests you get in your area.

We spray our plants preventively for pests. Once a pest problem takes hold, it is often too late. A good tactic is to switch up your product every three days to prevent the insects from building up a tolerance to your pesticides. Do be careful which products you mix, though.

Use a misting spray or an atomizer to spray your plants; ensure that the spray gets onto the underside of the leaves because that is where the bugs usually are. The spray also needs to get into the soil to get the larvae of some of these pests. So the application method is just as important as what pesticide you choose.

Growing Hemp for Flower Products

Hemp flowers are one of the most popular crop types because they are easy to monetize based on current demands. When growing hemp flowers, the important characteristics you need to focus on are:

  • The density of the flowers – this will ensure you still have product when issues like pests and mold strike.
  • Structure – depending on the product, you may have a little bit of wiggle room. If you are selling the flower itself, you will need a very tight structure.
  • Flavors, smells, and terpene profiles – buyers will have different preferences.
  • Testing standards – hemp is subject to stricter standards for pesticides, mold, and heavy metals. Keep updated with the testing requirements.

Processing Hemp Flowers

A large part of the success of your hemp product will rely on not just growing it correctly but processing and packaging the flower correctly. The key steps are:

  • Trimming – you can use an industrial trimming machine or human trimming, depending on the scale of your business. A correct trimming process is vital to ensure you don’t damage the product.
  • Drying the flower
  • Bucking the stalks – you need to remove the stalks to produce a clean product.
  • Tum the sun leaves and sugar leaves – your flower should be left with only the bud to package and sell.

Some people may grow their crop for both flower and biomass. This can be beneficial, but the flower really gives the cannabis product its high oil content, so if you package just the biomass, it can seem like a lower quality product simply because it is missing the flower.

Hemp is an emerging market, so many people are pedaling false advice and products under pretty claims trying to cash in on a new market. You really need to take new advice with a grain of salt and do your own research to determine if there is merit or not.

Bonus: Looking for a cost-effect method for drying hemp? Check out these DIY Hemp Drying Floors from Hops Harvester >

Clones vs Seeds

You can plant your crops using seeds, clones, or a mixture of the two. Here are the main benefits of seeds and clones to help you decide what is best for you.


  • Seeds allow you to easily scale your hemp farm to multiple acres, whereas clones you need to produce in advance.
  • Seeds have a deeper root structure and therefore are more tolerant to drought
  • Better pest resistance


  • Clones are great for smaller-scale crops
  • They allow more stability in terms of making them from hemp plants that thrived in your conditions.
  • Guaranteed female plants


The team at Clear Safe Labs were kind enough to answer some questions from our community.

Do Male or Female Plants Produce Better Quality For Hemp Fiber?

You need both male and female hemp plants for hemp fiber. Neither will have a huge impact on the quality of the fiber, instead, focus on the amount you’re watering it and what size crop you have.

Is It Better to Sell to A Wholesaler or Direct to Manufacturers

Most farmers will benefit from selling their products to a wholesaler. A wholesaler has the business relationships with the distributors and brokers. Some farmers have found success marketing their own biomass, because they have been in the game long enough to have the business connections. Ultimately, you need to do what is best for you because at the end of the day, the main thing is that you sell your product. The more people out there selling your product, the more you will be able to move.

How Much Manpower Is Needed to Plant, Harvest, and Maintain an Acre of Hemp Plants

There is no general answer for this, unfortunately. Things like the size of plants, style of your field, distance from your house will impact the manpower greatly. Also, the degree of automation you have for daily processes like watering will also impact this number.

Most people use a crew of four or five people to maintain one or two acres on one field. You may need additional hands for harvest.

Where Can I Find The Varieties of Seeds to Select the Best Type For My Area’s Genetics?

Visit a reputable hemp genetics provider. Clear Safe Labs have access to a few strains that are doing well across the country as well as strains specific to upstate New York. They also have contacts in the industry that may be able to help.

How Do You Start Growing For CBD Oil?

CBD oil is a massively oversaturated market at the moment, and it wouldn’t be wise to go all in. You should experiment with an acre or two and really learn the processes, and see what scope you have before you start investing in the equipment and large acreage. So, try out hemp growing for CBD oil, but make sure you don’t bite off more than you can chew.