Silicone Injection Port
2 min

Magic Mushroom Cultivation: How To Make a Silicone Injection Port

2 min

Contamination is a real and prevalent risk for any home magic mushroom grower, so how do you minimise risk? By adding a silicone port and air exchange to your growing jar or bag!

When it comes to growing your own magic mushrooms, there are few things more frustrating than finding that after all your hard work and effort, the grow has been contaminated due to a lapse in sterility. It is a situation many novice psychonauts will know well; even after going to the effort of creating a spore syringe in a sterile environment, things can quickly go downhill if the inoculation process is not done with care. One way people try to avoid this is an inoculation jar – a glass jar that is filled with your growing medium. What makes these jars so special is the lid, which has been manually modified to create the perfect inoculation environment.


So how do these help? Well, assuming that everything else you have created is sterile, such as the spore syringe and growing medium, a silicone injection port and air exchange will ensure that the growing environment remains sterile while the mycelium takes hold – a particularly vulnerable stage of the whole process. It does this by making sure no contaminants get in during or after inoculation while still allowing the jar to breathe.

To make these ports, you will need to modify the lid of the jar. First, we will start with the injection port.


For this you will need:

  • A glass jar with lid
  • A Drill with 6.5mm drill bit
  • RTV silicone sealant 
  • Paper


  1. The first thing you need to do is drill two holes into the jar lid. It is better to do each one off-centre so that there is plenty of room between them.
  2. Cut a few squares of paper that are large enough to cover the hole.
    Note: Although you have drilled two holes, only one is used for the injection port. The other will be used later for the air exchange port. Only perform the below on one hole.
  3. Ensure the lid is clean, the take your silicone sealant and create an outline around one of the holes, on the underside. Once done, fill in the rest of the circle with sealant. You create an outline around the hole to help do this and hold it all together.
  4. Repeat on the other side of the lid.
  5. Take your paper squares and carefully place one on each side of the lid, on the silicone. Press each side down gently so that it flattens.
  6. Carefully place the lid to one side to dry. Ensure that the silicone doesn’t touch anything put paper, or it may stick to it as it dries.
  7. Once dry, carefully peel off the paper. It should leave you with a nice flat silicone injection port. This will self-heal upon use, ensuring nothing but the syringe goes through it!


Now that you have a safe port to inoculate your growing medium with spores through, it is time to make an air exchange port, which will allow the jar to breathe without risk of contamination.

To do this you will need:

  • Aquarium fibre cotton filter
  • Pliers


  1. You should already have a second hole drilled in the lid from when you made the injection port. This will be used for air exchange port.
  2. Take a strip of your aquarium filter material and roll it into a small roll the size of the hole.
  3. Now fold it over in half and cover the top with more material. This will create a smooth uncompromised layer to work with.
  4. Cut the material so that you are left with your small roll, then from the bottom of the lid, work the covered centrefold through to the top so that pokes out about 1cm from the top. This is quite tricky, and you may need pliers to help pull it through. You want it to be tight so draughts and breezes do not get through.
  5. Cut any excess loose material away from the bottom. You now have an air exchange port! The filter material will allow fresh air to get through, catching any particles or materials that may cause contamination.

There you go, you now have a complete lid with an injection port and air exchange to ensure your mycelium can grow without pesky contaminants making life difficult. This method can also be adapted to add extra security to inoculation bags, using the silicone and some gauze over the injection point to ensure inoculation remains contaminant-free! Some bags even come with the injection port built in, taking away all the worry!

Check out this easy-to-follow instructional video if any of the above steps are unclear. 

Luke Sholl
Luke Sholl
Luke Sholl has been writing about cannabis, the wellness potential of cannabinoids, and the positive influence of nature for over a decade. Working with several cannabinoid-centric publications, he publishes a variety of digital content, supported by strong technical knowledge and thorough research.
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