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How to keep weed fresh

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Contents

  1. Moisture and mold in marijuana
  2. The best temperature to store your cannabis
  3. Light and oxygen change cannabis composition
  4. Extending the shelf life of weed
  5. Frequently asked questions

Over the years, cannabis packaging in legal or medical marijuana regions has become more sophisticated, with features designed to maintain freshness. The packaging on your marijuana products might have a harvest date on them, but flower doesn’t come with an expiration date. So even with producers improving their packaging, you might find yourself wondering: how long does weed stay fresh?

About the two worst ways you can store your bud are on a tray, exposed to oxygen and light, and in a plastic sandwich bag, just like a dealer’s bags that are common on the illicit market. A number of environmental factors affect how well the plant grows, but cannabis storage is also a key component of quality and freshness. Cannabis needs the right balance of conditions to remain fresh.

Cultivators go to great lengths to ensure your flower is packaged with optimal moisture content, usually in opaque packaging to keep light out. You’re probably wondering why you still see transparent and clear containers lining your dispensary’s shelves.

Well, old habits die hard and the practice of seeing and smelling the product on the shelf is still a key component for many people when it comes to deciding what to purchase. Some companies have even started replacing the oxygen in their packaged flowers with nitrogen to help maintain freshness.

For the best possible marijuana experience, you need to know how to keep weed fresh and how to store weed properly. This guide will give you everything you need to know.

Moisture and mold in marijuana

Moisture and water make a big difference when it comes to degrading the shelf life of cannabis.

While no two cultivators dry their flowers in the same way, all cultivators dry their flowers and then put them through a process called curing.

When cannabis is properly cured, it allows the moisture that is trapped inside the bud to slowly dissipate from the flower without changing any of the cannabinoids or losing terpenes. Once the flower has the perfect moisture content, usually between 6% and 9%, it is placed into packaging from which excess oxygen has been removed. When you take it home, it’s important to try to maintain that balance.

Once the flower has the perfect moisture content, it is placed into packaging from which excess oxygen has been removed. When you take it home, it’s important to try to maintain that balance. Photo by: Gina Coleman/Weedmaps

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If you lose too much moisture, it can change the integrity of your flower. Your flower will become brittle and lose essential terpenes that affect potency and taste. On the other hand, with too much moisture or water, the consequences are more serious. So serious, in fact, that the American Society for Testing and Materials (ASTM), which develops technical standards across many industries, published the “Standard Specification for Maintaining Acceptable Water Activity (aw) Range (0.55 to 0.65) for Dry Cannabis Flower” in May 2018.

The ATSM defines water activity as “the (quantitative) capability of the cannabis flower in a sealed container to affect the humidity of the container’s headspace air.” Headspace is the air that surrounds the flower. Water activity measures vapor pressure against pure water. If water activity is 0.55, it is 55 percent of water.

During storage, water activity cannabis should remain within a range of a minimum of 0.55 and a maximum of 0.65. Water activity increases with temperature, which is why light and temperature control go hand-in-hand as best practices for how to keep weed fresh.

The relationship between moisture content and water activity is complicated, and the cannabis industry is still striving to determine the optimal moisture content for packaged flower.

What we know now is that a relative humidity level anywhere above 65% can significantly increase the likelihood that your weed will end up growing mold. According to the American Herbal Products Association, the drying process will dehydrate cannabis until it has a moisture content of less than 15%, and the curing process is where the remaining moisture is slowly removed to retain the volatile oils.

The best temperature to store your cannabis

To extend the shelf life of marijuana, it should be kept in a cool, dark place at or slightly below room temperature. The ideal temperature to store your weed is below 70 degrees Fahrenheit, or 21 degrees Celsius.

High temperatures combined with high moisture activity and relative humidity can lead to mold and mildew. Mold thrives between 32 and 120 degrees Fahrenheit, or 0 to 49 degrees Celsius, and growth is most active between 70 and 90 degrees Fahrenheit, or 21 to 32 degrees Celsius.

High temperatures and arid environments dry out your flower and evaporate sensitive terpenes, which ultimately change the effects and taste of the flower. This is why some cultivators skip drying and make live resin extracts to preserve all the monoterpenes that are lost during the drying process.

Lower temperatures are not as problematic, but they can make it harder for tetrahydrocannabinolic acid (THCA) to decarboxylate into tetrahydrocannabinol (THC). Lower temperatures will reduce the potency of the flowers when they are smoked or could make the trichomes brittle on the plant, causing them to break off when they are removed from the cold environment.

Light and oxygen change cannabis composition

Exposure to light is the biggest culprit when it comes to aging weed. This has been known since at least 1976, when a study published in the journal Pharmacy and Pharmacology explored what happens to the stability of cannabis under various conditions. It concluded that light is the single largest contributor to loss and deterioration of cannabinoids and suggested that “carefully prepared herbal or resin cannabis or extracts are reasonably stable for 1 to 2 years if stored in the dark at room temperature.”

Ultraviolet (UV) light will always degrade your weed, even if you store it safely in glass jars. So, while the clear glass Mason jars you see in the marketplace look nice, they won’t protect your purchase the way an opaque container will. If you really like to look at your marijuana, a brown container will filter out visible ultraviolet light — that’s why brewers use them to bottle beer. Meanwhile, green containers will block out roughly 30 percent of UV rays.

As time goes by, prolonged exposure to light and air will gradually convert THCA into THC. At the same time this is occurring, existing THC is being converted into cannabinol (CBN), a cannabinoid that does not create the intoxicating properties that THC delivers.

Ultraviolet (UV) light will always degrade your weed, even if you store it safely in glass jars. Photo by: Gina Coleman/Weedmaps

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And it’s not just THC that’s affected. Cannabidiolic acid (CBDA) can transform into cannabidiol (CBD) with enough exposure, and THCV will degrade into CBV. During this time, your weed could potentially become less potent.

In addition to playing a role in the conversion of cannabinoids, oxygen can also oxidize essential terpenes and change the overall aroma of the flower into a grassy, haylike smell.

To reduce exposure to oxygen, make sure there aren’t many air pockets in your container. You should always store your weed in an airtight container. Don’t use very large containers to store small quantities of weed, as this leaves too much air inside the container with your herb.

Of course, it is inevitable that some amount of oxygen will get into your sealed package once it is open, but you can limit the amount of time that the jar is opened and the number of times it is opened.

If you store your weed in sealed bags, remove as much air as possible before sealing. Vacuum-sealing weed can be a reliable, long-term storage solution for your stash. If you go this route, be sure you follow these tips to avoid inadvertently damaging your weed:

  • Try to avoid vacuum sealing your marijuana in plastic that contains bisphenol A (BPA). This chemical is a key ingredient in many types of plastic, but it has proven to be harmful to humans. And unfortunately, if you store your weed in plastic containing BPA, some of those dangerous chemicals could leach into your marijuana.
  • Handle your weed delicately. Plastic easily builds up static charges that can pull trichomes off your buds. Trichomes are the cannabinoid- and terpene-rich hairlike glands all over cannabis flowers, so you’ll want to avoid damaging them.

If you plan on storing your vacuum-sealed weed in the freezer, know that freezing will also make your trichomes vulnerable to damage, as they will become brittle.

Extending the shelf life of weed

Knowing how to store weed properly will help you get the most out of your cannabis experience. Ultimately, the key to extending marijuana shelf life is all about limiting exposure to the elements. When it’s time to open your container, pull out your flower and immediately close your package. Don’t let it sit open, and avoid windy or highly ventilated areas.

To maintain the right level of moisture, use a salt-based control sachet to maintain the ideal relative humidity. According to the ASTM standards (D8197-18), “a salt-based control sachet designed to maintain a relative humidity of 0.55 to 0.65 in a sealed container can be used to maintain optimum storage conditions.”

Additionally, you can store your marijuana in a cannabis humidor box, which has been designed to maintain the ideal humidity for marijuana. There are currently several models available on the market.

Whatever you do, be sure you don’t use a cigar humidor to store your weed. Cigar humidors are typically lined with cedar wood. The oils in the wood help enhance the taste of cigars, but those same oils tend to harm cannabis. Similarly, humidors for cigars often use sponges or propylene glycol to create humidity that are ideal for tobacco, but are much too high for cannabis.

In the past, to remedy dry weed, people would add an orange peel to their bags to keep the moisture content, but this greatly increases the likelihood that mold would be introduced. In addition, the water activity of orange peels is unknown and the aroma of the peel could alter the flavor and aroma of your weed.

Nowadays, you can use the same humidity control packs, such as Boveda packs, to reintroduce moisture if it is too dehydrated. This will not reintroduce terpenes that were lost, but it will ensure that you don’t have a harsh smoking experience.

To keep your weed in tip-top shape as long as possible, take careful steps to avoid exposure to light, moisture, oxygen, and extreme temperatures. Photo by: Gina Coleman/Weedmaps

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Like almost everything else, weed doesn’t last forever. Over time, changes to the molecular structure occur with exposure to heat, light, and moisture.

When cannabinoids and terpenes experience very high or very low temperatures, dry up, are exposed to too much moisture, or are left in the presence of light, chemical changes that will degrade the potency of the flower and could alter the taste and mouthfeel may occur.

As terpenes are exposed to environmental changes, they can oxidize or evaporate, creating a change in aroma and effects. And even though all weed degrades over time, the process can be slowed down if you control the temperature, moisture, and the amount of oxygen your flower is exposed to. To keep your weed in tip-top shape as long as possible, keep an eye on the harvest date on the packaging and take careful steps to avoid exposure to light, moisture, oxygen, and extreme temperatures.

Frequently asked questions

What’s the best smell-proof container for weed?

The simplest way to keep your stash smell proof is to make sure it’s stored in a solid airtight container with a sealable top. Sealable glass jars, like a Mason jar, are typically sufficient for storing your stash and keeping in the smell. Some cannabis consumers also use large medicine bottles to keep their stash from stinking up their living space. Online retailers also offer a variety of odor-proof containers designed specifically for weed storage.

Is refrigerating or freezing weed bad?

Refrigerating or freezing weed is definitely preferable to storing it in an area that’s too hot or humid. And though some cannabis consumers report successful long term weed storage through freezing, it’s more than possible to lose freshness and potency to icy temperatures, as trichomes may become brittle and break off more easily. Storing your stash in an opaque, sealed container, in a relatively cool place with minimal sunlight is your best bet for long term storage with minimal degradation.

How to keep weed fresh Copy article link to clipboard. Link copied to clipboard. Contents Moisture and mold in marijuana The best temperature to store your cannabis Light

What’s the Best Pot? Containers Explained

Table of Contents

Which growing container works best for cannabis? What is it that makes some containers better than others?

The answers are contained in the roots of your cannabis plants. The idea behind choosing the right container is to pick one that is going to provide the best possible environment for your cannabis roots. Your roots are like the “heart” of your of your cannabis plant. They need to be healthy for your plant to get nutrients and grow.

What do marijuana roots want?

Happy cannabis roots want…

Moist at all times – roots die when they dry out! Good watering practices combined with a great growing medium will make sure your roots never dry out

Oxygen – your roots “breathe” oxygen, so one of the best things you can do for them is make sure they always have access to plenty of oxygen – more oxygen to the roots = faster growth

Nutrients – your roots “find” nutrients at the roots, and then deliver them to the rest of the plant, so making sure your plant has easy access to nutrients will help your plants thrive and make buds

pH Management – Some nutrients are sensitive to the pH of their environment. When exposed to the wrong pH, the molecular form of these nutrients actually changes. Nutrients in the wrong chemical form become unavailable to your plant roots. Exposing nutrients to the correct pH reverts them back to a form your roots can take in.

Bottled Cannabis Nutrients

Managing pH is especially important when using bottled nutrients.

Using bottled nutrients gets the nutrients to your plant faster (which equals faster growth), but it also means you are in charge of managing the pH.

These systems deliver nutrients directly to the plant roots in their simplest form, but there is no “middle man” between you and the plant roots, leaving you in charge.

So if you’re using bottle nutrients, make sure you manage your pH!

Amended & Composted Soil

When starting your cannabis grow with properly amended and composted soil, pH isn’t as important for you to manage. Instead of managing pH, you need to manage and care for the bacteria and microorganisms in the soil. In a proper composted soil setup, the microorganisms deliver nutrients to your roots in the right form. They become the “middle man.”

Types of Containers

There are many kinds of popular rowing containers for cannabis gardens…

Standard plant container with saucer

Here’s a breakdown of those different container options…

Standard plant container with saucer

This is a container with a hole at the bottom for drainage, plus a saucer to catch the water.

Tried and true method

Easy to find at any gardening store

Saucer captures runoff water for easy disposal

Smart pots (fabric containers)

More oxygen to the roots

Prevents plants from getting “root-bound” via “air-pruning” from the sides

Since growing medium dries out from the sides, smart pots make it difficult to overwater your plants, but that also means you will end up watering more often

Since smart pots dry out faster than regular cannabis containers, you should get double the size as your normally would, and it’s recommended your final size should be at least a 5-gallon container (anything smaller than that dries out in just a day or two!). So if you would normally get a 2-gallon container, you’d want to get a 5-gallon smart pot.

Need an extra large saucer or a tray to capture runoff water – smart pots don’t come with a saucer or tray and they seep out water from the sides

Air pots

More oxygen to the roots

Helps prevent plants from getting “root-bound” via “air-pruning” from the sides

Since growing medium dries out from the sides, air pots make it difficult to overwater your plants, but that also means you will end up watering more often

Although water seeps out the sides when watering, air pots are tall and thin so you can use a regular size saucer for each container

Hempy Buckets

Like a regular plant container except instead of having drainage holes out the bottom, they are located near the bottom on the sides

This leaves a small pool of water in the bottom of the container after watering

Need to water less often with hempy buckets, which is a great advantage when growing larger plants that drink a lot

Can sometimes lead to root or nutrient problems since stagnant water can sit at the bottom of the container and any nutrient buildup never gets rinsed out

Hydro

How to Catch Water Runoff

The two most popular ways of capturing runoff water in small containers are…

Individual saucers for each container

Trays to catch runoff from several containers

Saucers

Most regular plant containers come with a matching saucer. These are placed under the plant and catch the runoff water for each individual plant.

When using a container that lets air in through the sides (such as a smart pot or air pot), you will need a larger than normal saucer to capture all the runoff water, since water will be seeping down the sides of the container.

One of the problems with saucers is you usually remove them from under the plants to empty the runoff water (always remove runoff – never let it sit so it’s seeped back up into the growing medium!). This is easy with just a few plants, but can become a problem when growing with a lot of plants in a small space. It can be difficult to get to the saucers in the back after the grow space has been filled up with plants.

If you’re having trouble emptying out all your plant saucers, you may want to consider an alternative to regular saucers…

Trays

If you want to capture the water from a lot of plants in one space, I recommend using a tray set one a slight incline, so the part of the tray furthest away from you is raised slightly off the ground.. With even a tiny incline, the runoff water will pool at the front of the tray, and a wet vac can be used to capture all the water from the plants. This can be a lot easier than emptying saucers, depending on your setup.

As a bonus to using a tray, you won’t have to move your plants around as much, which results in better and faster growth. Plants don’t like being moved around if you can help it.

How to pick up the water from your tray?

  • Wet/Dry vacuum
  • Water transfer pump

I found the “Bucket Head” attachment at Home Depot which costs about $25 and can be attached to any standard bucket, turning it into an ultra-cheap wet/dry vacuum.

Which Size Container?

Final Size Container for Desired Plant Size – General guide

When choosing the size of your containers, you must think about the final size of your plant. Bigger plants will need bigger containers, while smaller plants grow best in a relatively small container. You need to match the size of your plant with the size of your container.

A general guide is to have up to 2 gallons per 12″ of height. This isn’t perfect, since plants often grow differently, and some plants are short and wide instead of tall, but this is a good rule of thumb.

So if your final (desired) plant size is…

2-3 gallon container

3-5 gallon container

6-8 gallon container

8-10 gallon container

12+ gallon container

Lots of different types of containers will work for growing cannabis as long as it has good drainage holes out the bottom

If you’re using a Smart Pot (fabric pot) or any container that lets in oxygen from the sides, you’ll get faster growth than a hard-sided container. However you will also need to water your plants more often since the soil will dry out more quickly.

Therefore it’s recommended to get twice the normal size if you get fabric pots so the soil doesn’t dry out as fast.

Get twice the normal size if the container lets oxygen in from the sides (like fabric pots and air pots)

Which size container should you start with? Start Small

To start, your plants will do best in a relatively small container. This helps prevent the chances of overwatering (since the container is so small) and since a small container dries out quickly, it will deliver more oxygen to the roots.

Many growers start their plants in a solo cup or a 1-gallon pot.

As mentioned earlier, some growers start their marijuana plants in their final container, which is usually larger than a 1-gallon pot. Starting in a big container isn’t as simple as starting with a small container, and can cause slower growth at first, but here’s you can take to get a seedling to grow quickly in a large container.

Once the leaves reach the edges of the solo cup it’s time to transfer to a larger container. These seedlings are getting close!

How to water seedlings or clones in a too-big container

When starting seedlings in a big container (bigger than 2-gallon), it’s important to slowly give just a little bit of water at a time until your seedling “grows into” its pot. This prevents overwatering, which slows down seedling growth.

By watering the right amount in the seedling stage, you can speed up growth significantly, especially during that first week or two.

For new seedlings you should give water in a small circle around the plant instead of saturating the whole container.

Don’t give water again until the top inch of potting mix is dry to the touch (which should be less than a few days if you did your job right). This makes sure your seedlings get a perfect mix of air and water so it grows as fast as possible.

Make sure to give water slowly in a small circle around seedlings until you get runoff water out the bottom of the container. This makes sure that water is getting to your plant’s roots but isn’t over-saturating the container.

After plant has started to “grow into” it’s container, the top inch of potting mix will start drying out quickly (less than a few days). At this point, you can start normal cannabis watering practices which means you saturate the whole growing medium until you get about 20% runoff water

Summary
How to water cannabis seedlings or clones in a too-big container

Beginning Stage

This is for when you’ve just planted your cannabis seeds or clones in a too-big container. By giving your young plants less water at a time following the steps below, you prevent overwatering which can slow down seedling or clone growth in a too-big container.

  • Pour water slowly in a small circle around the base of the seedling (I first pour my water into a solo cup so that it’s easy to pour water around each plant).
  • The circle should be

2 inches in every direction from the base of your seedling (or if your seedlings are bigger, about the width of the leaves).

  • Every time, make sure to continue watering slowly in a circle until you get runoff water out the bottom of the container. Make sure to remove runoff water so it doesn’t get re-absorbed through the bottom of the container.
  • Don’t water again until the top inch (up to your first knuckle) is starting to feel dry to the touch.
  • Regular Watering Stage

    Once your marijuana plants have established healthy root systems that can support the size of your container, you can start watering as normal.

    • Once the top of the growing medium is drying out quickly, in less than than 2-3 days, you’re past the beginning stage.
    • Switch to normal watering practices. This means that you are watering the entire container until you get 20% runoff every time. Then don’t water again until the top inch (up to your first knuckle) is starting to feel dry to the touch.

    Important: Always wait until the top inch (up to your first knuckle) is starting to feel dry to the touch before watering your plant again. This prevents both overwatering and fungus gnats 🙂

    Transplanting for faster growth

    Transplanting means that you start your plants in a relatively small container, and then transplant the plants as needed so that their roots never run out of room.

    Transplanting will provide your plants with faster growth if done right. This is because transplanting allows you to set up an environment where your roots are getting access to plenty of water and air. However, transplanting can stress your plants (and slow down growth) if not done properly. When transplanting, it’s important to carefully move plants so that their roots are not disrupted in any way. This means moving plants before they get root-bound, and creating a hole in the potting mix of their new container so the plants can be placed right in without disturbing the roots.

    If you plan on starting your plants in a small solo cup and transplanting your plants to bigger containers as needed, take a look at this transplanting guide.

    While transplanting makes it easier to give your young plants access to plenty of water and air, it can stress the plants if not done right, and it can also be too much work for some growers. So many growers start their plant in it’s final container.

    When seedlings or clones are started in a large container, it can be difficult to get enough air to the roots until the plant is bigger and drinking a lot. Thisis because when the potting mix gets soaked, the seedling roots just won’t be able to drink it fast enough, and the roots will end up sitting in stagnant water with very little acces to oxygen. The growing medium has to dry out on it’s own, which can take a while, and your plant will be droopy and overwatered until the roots start getting access to air again.

    Some growers start their seedlings or clones in a bigger pot, or even the final container they plan to use. While this can slow down growth of young seedlings, you can minimize this effect by watering young plants correctly when they’re started in a too-big container.

    Here’s a very quick breakdown of some of the most common cannabis growing mediums for a hand-watered grow. This is not a comprehensive list, but should give you a place to start your research. Each of these different growing mediums have pros and cons.

    Soilless (coco coir, perlite, vermiculite, etc)

    Store-Bought Soil

    Easy to find at any gardening store

    You can start with nutrient-rich soil and transplant several times throughout the grow to give your plant what it needs after it’s used up all the nutrients in the soil in it’s current container. If you choose not to continue transplanting to give cannabis more nutrients, you will need to use cannabis nutrients to make sure plants are getting what they need

    You will need to manage and adjust pH for a soil grow, especially if using bottled cannabis nutrients

    Composted Soil – learn about composting your own soil

    You will need to amend and compost your soil to use this method, which can take a lot of time, or buy amended and composted soil from a quality source

    When done right, there’s no need for bottled nutrients or adjusting pH

    Many growers claim that composted organic soil provides the best bud taste and smell

    Soilless Potting Mix – (coco coir, perlite, vermiculite, etc)

    Faster growth than growing in soil

    Starting at the seedling stage, you will need to use cannabis nutrients made for hydro, since soilless mediums do not come with nutrients

    Managing and adjusting pH is crucial to success in a soilless growing medium

    Less likely to get pests or bugs

    How much grow medium to get?

    In the USA, a “3-gallon” plant container usually holds less than 3 gallons (same with 1-gallon, 2-gallon, 5-gallon, etc.). It’s a weird convention in the USA which means a direct conversion between listed gallons and gallons of soil (or conversion to liters) isn’t accurate. A “trade” gallon holds about 3/4 of a “real” gallon. This makes it easy to buy a lot of extra grow medium. To make things more confusing, in the USA not every 3-gallon pot actually holds the same amount of grow medium (it’s not totally standardized). Additionally, smaller companies often give the actual amount. Other factors change how much grow medium you need, including how high you fill the pot and how much it gets compacted. When in doubt, get the listed amount and you’ll always end up with enough or extra grow medium.

    What’s the Best Pot? Containers Explained Table of Contents Which growing container works best for cannabis? What is it that makes some containers better than others? The answers are ]]>