Hash Contaminants & How To Keep Trichomes Clean


Todde Philips

🇺🇸 Retired veteran, father, rock-climbing expert & rosin connoisseur.

Bubble Wash Bags, the sieving bags used in the Ice Water Extraction method for making bubble hash, separate trichome heads from cannabis source material. Hash makers use these trichome heads, also called loose resin, to create a variety of cannabis products, most commonly pressed Rosin and Temple Balls. 

Hash makers essentially “wash” the trichomes away from the cannabis flowers and trim leaves on which they grow with an ice water bath, then run this mixture through a series of sieves to capture the resin while everything else can flow through as waste. 

But sometimes, contamination in the form of bugs, dust, sand, and even pesticides can get caught in the sieving bags along with the resin. And contamination in the bags can easily lead to contamination in the final product. Therefore, the goal is to minimize all contaminants on the starting material as much as possible before starting the Ice Water Extraction process. 

While there will always be some level of contamination, even if it’s extremely limited, there are things that hash makers can do to keep trichomes clean during the growth, harvesting, and preparation phases leading up to extraction. 

Common Forms of Contamination:

  • Bugs and Bug Parts 
  • Bug Excrement 
  • Dust, Sand, and Dirt 
  • Pet Hair 
  • Fungus or other pathogens


How To Reduce Contaminants and Keep Trichomes Clean

Different types of contaminants are more or less common depending on the growing environment, whether indoor or outdoor. Let’s look at ways to reduce contamination in the environment both inside and outside of the grow room, then see what we can do to minimize contamination once a source is identified. 

Trichomes are sticky by nature, and they’re like little magnets for contaminants to stick to. By reducing the amount of contaminants in the surrounding environment when possible, hash makers have an easier time keeping particulates away from their resin. 

Bear in mind, prevention is always better than treatment. 

Outside of the Grow Room

Reducing the concentration of contaminants in the direct vicinity of your grow facility translates into less contamination getting inside the facility and ultimately sticking onto your resin. 

Here are a few things that growers can do to keep contaminants right outside the grow room down to a minimum:

1. Keep the grass cut low on the grounds directly outside the grow room. Remove shrubs and bushes that will attract more contamination and even potentially become breeding grounds for animals and pests. 

2. Avoid planting pumpkin, squash, cucumbers, or zucchini anywhere near the facility. These plants are especially attractive to certain insects and pathogens that can also like cannabis, so they will likely try to find their way inside the grow room.


3. Scout out diseases or infestations on plants growing right outside of the grow facility. Remove any plants that look problematic. 

4. If you’re setting up a grow space inside your home, check all other plants that are inside your home. Give all your plants close inspection with a magnifying glass. It’s very easy to spread pests and infestation on clothing and skin. 

5. Create walkways covered with gravel, stone, or concrete for walking  around and entering the grow facility. These pathways should be cleaned and swept regularly. Organic matter on these walkways will harbor both fungus and insects, even through the winter months.

6. Don’t take gardening tools that have been used in outdoor gardens into your grow room. 

7. Keep pets out of the grow room. 

8. Be mindful about your growing medium, for example making compost outside and bringing it into your grow room. 

9. Wash your hands thoroughly every time you enter the grow room. Also use an antibacterial disinfectant. 

10. Filter all air that comes into the grow facility. 

Inside the Grow Room

Hypervigilance inside the grow facility is key to keeping your trichomes clean and preventing excessive contamination from making its way into your hash. Here are some best practices to apply inside your grow room:


1. Put disinfecting mats on the floor right inside of every door leading into the grow facility. 

2. Only use tools that have dedicated use for inside the grow facility. Don’t use tools inside the grow that have already been used elsewhere. 

3. Attach a plastic curtain inside of every doorway of the grow room, and then install an air shower. 

4. Create positive air pressure inside the grow space. 

5. Don’t dry sweep the floors, but sweep only after applying some water. Dry sweeping just releases dust and debris into the air, where it will land on your trichomes. Swipe and scrub clean the floors. Immediately collect anything that’s swept up and place it into plastic bags, tie the tops, and remove immediately. 

6. If you have porous walls inside the grow room, cover them with plastic sheets. 

7. Use silicone to seal floor and wall joints, which minimizes the pathways things can use to travel into the grow room. The type of silicone caulk made for use in bathrooms works well for this.

8. Everyone who comes into the grow facility should use protective clothing, including disposable gloves and booties. 

9. Remember to keep all house pets outside of the grow room and away from the doors. 

10. Dehumidify the air with a high quality dehumidifier. 

11. Check all plants daily for infestations and disease. 

12. Sterilize everything after each harvest. Grow containers, walls, floors, etc. 

13. Use insecticides and fungicides appropriate for each stage of plant growth. Establish a regular schedule for preventative application and stick with it. 

14. Throughout the grow cycle, periodically wash and sanitize all tools and equipment used in the grow room. 




Minimizing Damage

No matter how diligent you are, sometimes there’s going to be issues with contamination inside the grow room. When this happens, there are some things you can do to minimize the damage and keep the situation from spiraling completely out of control. 

Here are some tips to keep in mind:

1. When you identify and remove problem plants inside the grow room, tightly sealed plastic bags are your friend. Don’t carry these contaminated plants through the rest of the grow room to the outside. Place them in a sealed plastic bag first to prevent spreading the contaminants throughout the grow room. 

2. If you see any signs of pests or pathogens, remove those leaves or branches and put them immediately in a tightly closed plastic bag for disposal. Don’t let hot spots spread!

3. Always keep a supply of  insecticides and fungicides on hand and be ready to apply at the first sign of trouble. 

4. If you’re growing organic and can’t use traditional insecticides, try to keep things in check with friendly predators like ladybugs and predator mites.


Even when you follow all of the steps above, some contaminants will still end up on your trichomes. And if you’re growing outdoors, there’s no way to keep bugs, dust, sand, dirt, etc. away from your resin. Just minimize the amount of contaminants when possible and avoid pest infestations. 

It's a great idea to clean and rinse your flowers immediately after harvest, to wash away contaminants before processing. Check out our article How To Rinse & Clean Your Flowers Before Washing Hash.

Once you wash the buds during Ice Water Extraction, some remaining contamination will get released into the water. Some of it will stick to the resin and get trapped in the sieving bags along with the hash. This is why it’s important to do a good job of spraying down the trichomes with a stream of cold water. 

Read our article called How To Use Pressurized Water To Clean Contamination from Bubble Hash to learn more. 



For hash makers, the pursuit of purity is paramount. The quest for clean trichomes is an art in itself. Keeping trichomes clean is a persistent challenge, and avoiding contamination is the game that never ends. From bugs and pesticides to dust and dirt, these unwelcome intruders can hitch a ride on trichomes and find their way into the final product, compromising its quality and safety. However, there are proactive steps that hash makers can take to safeguard their trichomes from contaminants.

Prevention is the watchword, and it begins before the first trichome is even harvested. From maintaining the grounds outside the grow facility to implementing stringent cleanliness protocols inside the grow room, every detail matters. Keeping contaminants at bay requires a multifaceted approach, from using dedicated tools to sealing floor and wall joints with silicone. And when issues do arise, swift action and containment become crucial to minimize damage. 

With careful planning, consistent maintenance, and a commitment to cleanliness, hash makers can strive to keep their trichomes as pure as possible. 

Thoughts? Let us know by joining our secret Facebook group. Hang out with a community of like-minded solventless heads like yourself. Ask our head extractor questions, share your latest press and learn from hobbyists and experts in the industry.


Why is it important to maintain positive air pressure inside the grow room for hash production?
Maintaining positive air pressure inside the grow room is essential because it helps prevent contaminants from entering the room. This pressure differential ensures that air flows outward from the grow room, minimizing the infiltration of dust, insects, and other contaminants that could compromise the trichomes' cleanliness during the hash-making process.

How does contamination affect the quality of hash production?
Contaminants such as bugs, dust, sand, pet hair, and pesticides can get caught in the sieving bags during the hash-making process, potentially leading to contamination in the final product. This can compromise the quality and safety of the hash.

What are some common forms of contamination hash makers should be aware of?
Common forms of contamination include bugs and bug parts, bug excrement, dust, sand, dirt, pet hair, and pesticides. These contaminants can be problematic for hash production.

What steps can hash makers take to reduce contamination in their grow environment?
To reduce contamination, hash makers can implement measures both inside and outside the grow room. These include maintaining clean walkways, avoiding certain plants that attract pests, filtering incoming air, and using protective clothing.

How can hash makers minimize damage when contamination occurs despite preventive measures?
When contamination occurs inside the grow room, hash makers should use sealed plastic bags to contain and dispose of contaminated plants or parts. They should also be prepared with insecticides and fungicides and consider using friendly predators for organic cultivation. Additionally, thorough washing and spraying of trichomes can help remove contaminants during the washing process.


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