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The Four Times Growers Should Test Their Hemp

This article will explain when and why producers should test their hemp throughout the growing, harvesting, and selling lifecycle. Whether you're new to the subject or just looking for a refresher, these articles are meant to serve as a guide. The best times to test vary depending on your job function. Still, we recommend completing a full panel any time the product is sold (from farmer to processor, processor to wholesaler, and wholesaler to retailer).

This is the first article in a three-part series regarding hemp testing timelines. Each series will focus on a different role in the process:

1. Part 1: Producers

2. Part 2: Processors

3. Part 3: Retailers

Now we don't mean to sound biased, but testing is an important topic to understand for various reasons. You'll ultimately rely on test results throughout the entire hemp lifecycle. To track potency levels, ensure consumer safety, and even determine when and how to harvest (to name a few). We'll go into some more detail in the sections that follow. For now, understand that you should be thinking about and planning your testing intervals/procedures early.

One caveat before we begin: Adams Independent Testing (AIT) cannot tell you how often to test, what method you should use to harvest, or when you should harvest; however, we can provide general recommendations.

When is the best time to test your hemp as a producer?

At a minimum, you should submit for a full panel before you sell your product; however, we recommend testing throughout the entire farming process. Below is a high-level overview of when to evaluate your crop if you're a  grower/producer:

Now for the deep dive! Ast stated earlier, it's ultimately up to you to determine what and how often you want to test, but we have some recommendations to guide you through the process. Be sure to plot your data points to track and visualize result changes - especially if you're new to growing/cultivating hemp. This will help you learn how each stage affects your product and allow you to tweak methods accordingly. As a producer, we recommend testing through the following stages.Blog Images (5)

Testing hemp throughout the growing season

It's important to take a proactive approach when it comes to testing your crop's THC:CBD ratios. It helps you predict when to harvest, ensures your maximizing profit, and helps determine when the state should come out and sample your field and test against state regulations.

The goal here is to optimize your CBD or cannabinoid percentage while getting as close to 0.3% THC, without going over. To do this, begin submitting samples at predetermined intervals when the hemp starts to flower and bud. For example, some producers will bring samples in every Wednesday. Others will send in every 10 days and increase to twice per week as ratios start to peak. It's totally up to you!

CBD/cannabinoid percentages will increase gradually throughout the growing season. Toward the end of the season, this gradual increase will halt, and you'll generally see a sharp spike in THC. Plotting each test, whether on a graph or an excel spreadsheet, will help you measure differences and time your harvesting just right.

It's a very fine balance. Harvesting even a week or two early is leaving money on the table. On the other hand, if you harvest too late, the entire crop could go hot (exceed 0.3% Total THC) and will ultimately need to be destroyed. Keep in mind that many other growers will be contacting the state around the same time, so use your data points to predict when they should come out, and schedule with them early.

Contaminant analysis is also advised since hemp is known for cleaning the soil. In other words, it leaches everything out of the ground, soaking up heavy metals and pesticides used in the past. If you're concerned about heavy metals in your soil, if you know pesticides were used in a field previously, or even if a neighbor flew too close with a crop sprayer and it may have affected your plants, plan on running these tests.

If nothing else, test once before harvest for peace of mind. Growing, Harvesting, and drying is a lot of work and can be expensive. You don't want to go through all that labor only to find out that you can't sell the product.

Before Harvest

As you may already be aware, your harvesting method can significantly impact test results. If you intend to experiment with the various methods, label each sample accordingly to track how each process affects your results. For example:

  1. Chopped: stems, leaves, and buds all chopped together
  2. Combined: Harvested with a combine
  3. Hand-Trimmed: Just the buds and leaves, no stems
  4. Hand-Trimmed Bud: Buds only

Note: We'll expand more on experimental harvesting in a future blog post, so be on the lookout for that! For more information on how to sample a field, feel free to download our brief informational handout here.

Stems and leaves have a minimal amount of CBD in them but have a substantial amount of weight, so they drastically bring down your overall CBD percentage points. A common perception is that if the stems and leaves add on weight (and you're likely getting paid per pound per CBD point), it evens out; however, this isn't always the case.

AIT cannot make this call for you, but we do recommend testing a sample for potency before harvesting your entire field. You'll then know what to expect and can determine if your chosen method still makes sense. to really drive this point home, let's look at an example:

John decides to chop his entire field and doesn't bother testing potency first, figuring he can just submit for a full panel after harvest. He lines up a processor and arranges for testing before the exchange. When John gets his results back, however, the CBD potency level is 5%. He knows his processor (and most others) won't accept hemp with at least 8% CBD. Now what? It weighs more (generating weight points) because it includes stems and leaves, but it doesn't matter because he can't sell it to anyone. The CBD level is too low for extraction. John's options are ultimately limited:

  1. He can submit a new sample and hope for a small increase
  2. He can try to sort out the bud material by hand
  3. He may have to destroy the product
    Unfortunately, this example isn't uncommon. Many producers had to resort to culling buds by hand last year. Not only is this time-consuming, but it can also be difficult depending on your harvesting process.


Moral of the story: Save yourself time and money by testing for potency before harvest.

During drying/before storage

Please note that potency can shift if not handled properly, so we recommend performing potency and moisture evaluations throughout the drying cycle. Moisture testing is also important to ensure safe storage (i.e. prevent mold growth). These tests are quick, inexpensive, and lend peace of mind; yet so many people skip this step - ultimately running the risk of losing their crop.

Even though your hemp may feel dry to the touch, it could still be capable of molding and developing mycotoxins.  This is dangerous to the end consumer. You don't want to store too early, only to discover that it is full of mold when it comes time to sell.

Before Selling

You'll need a full panel before distributing your hemp to buyers to prove it doesn't contain pesticides, heavy metals, mycotoxins, etc. Whenever possible, work with the processor you intend to sell it to during testing. Currently, there's a lack of trust and knowledge in the industry regarding proper sampling procedures, and it's not uncommon for a processor to request a retest. Checking in beforehand saves you both valuable time and money

Even if the processor doesn't request a full panel, it's important to run one anyway and keep a copy of the certificate of analysis (COA) for your records. We're not here to oversell you; think of it more as an insurance policy. It's possible for contaminants, like heavy metals and mold, to enter the hemp after you grow it. if the product is flagged later down the supply chain, you can prove it was clean when it left your possession.

There are multiple ways contaminants can enter the product after you've sold it, and the material can change throughout its lifecycle. Examples include:

  • Knock-off vape pens: Heavy metals can enter through cheap vape products. Some vape pens manufactured from Chine have been found to contain lead.
  • Polluted water sources: Heavy metals may enter through a bad water source someone else is using.
  • Product mix: Pesticides can infiltrate when products from different producers are combined.
  • Improper Storage: Mold may grow from poor storage techniques.

A full panel doesn't only protect you, the seller; it also protects the buyer. So, don't be offended if they opt to retest it themselves anyway. All players have a stake in ensuring consumer safety. Regardless of what interval method you decide to test, securing a full panel before it leaves your hands is the best practice not to skip.

Why is testing so important?

To recap: not testing properly or at the right times could have serious implications on your business, reputation, time, and finances. It's important because it:

  • Serves as an insurance policy against third-party contaminants
  • Helps you maximize profit
  • Guides you in determining when the state should come out to sample your field
  • Aids you in predicting when and how to harvest
  • Assist in ensuring your crop doesn't go hot
  • Protects consumers
  • Grants you peace of mind

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