Professional Cannabis Cultivation

5) Media


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Lesson Summary:

In this lesson, Cameron discusses the media procedures you’ll use in you professional operation.


Lesson Transcript:

Hey everyone! I’m Cameron and in this video we’re going to be talking about media.

So prepping rockwool in a commercial facility requires big rolling bins, they’re probably about two hundred gallons, maybe you’ve seen a janitor with them, but they’re big massive black bins they come on wheels. Generally you’re going to need three-four of them. In the past I’ve seen the bins we use for doing whole plant harvest, same bins that we would use for prepping the rock wool. Generally these containers hold about two boxes of the 6x6x6 rockwool cubes, so you’re doing about one hundred cubes at a time, and it’s basically conveyor production style, you’ve got one guy that’s filling the bin, one guy that’s pHing the water, another guy guy that’s wheeling it down, and another guy that’s laying them out on the table and you’re just running in succession until your room is full.

One of the things that you want to do when you are prepping your rockwool is to be sure to pH the water. So when I’m prepping the rockwool, I want to be sure that the water that I’m charging my rockwool with is set to about a pH of 4.5, and this will get my rockwool up to the target of around a 5.5. pH, which is where I want my system to be running basically throughout the whole life cycle. 5.5 is my target on a rockwool based system. Also remember to prep our rockwool for about 30 minutes and in that time we’ve rockwool that is fully charged and prepped and ready to go.

One of the things I really like about rockwool is provides a nice balance between water and air in the root zone. Rockwool is really known for its draining potential, so generally in these commercial facilities what we would do is have one or two drip emitters that are plugged into the top of the rockwool and watering multiple times a day and that water is constantly draining off and creating that sort of perfect environment for that root zone.

When it comes to wicking vs draining, rockwool is much better at draining than it is at whicking. Although you could use rockwool in a wicking scenario, generally in a commercial facility you would not be flooding your tables, you’d be draining. Your rockwool would be draining because you have drip emitters set into your rockwool.

Other media choices besides RW could include things like peat and coco. If I had my druthers, I’d certainly go with coco. peat is in short supply, and unlike peat, coco holds no charge. So over time peat can start to retain some of the charge of past nutrient feedings, and it can begin to skew one way or the other which can start to create havoc over time in the root zone. So if I’m looking to use some media other than rockwool I would definitely recommend coco.

So Promix is a great example of a large scale commercial media. I have been in facilities in the past where in the interest of saving money in the short term, the buyer has gone with an inferior product, a slightly cheaper product than say the Promix which is sort of the more premium product, and what I can tell you is trying to save a couple dollars per bale in the short run can have sort of a cascading negative effect in the long run. These cheap medias, they’re not as clean, not as pure, and I’ve seen these things come in with what are almost certainly root aphids and other bugs and other impurities that are going to cause potential for catastrophic collapse. Inferior media can definitely pose detrimental problems to your cultivation. Impurities including things like pests and pathogens sometimes will come in on these so definitely do not skimp on the media. You want to go with the premium brand.

Another thing to be mindful of when you’re dealing with media types, you can sometimes get variations from bag to bag or pallet to pallet. So in an effort to try and create a uniform production, something you can always count on every time, this is again why I’m always leaning on rockwool which is basically always starting at zero. Getting a media that comes in a little bit hotter in one case, a little bit cooler in another case can start to create variations through your production.

Similar to the potential problems with inferior peat products, you can also run into inferior coco products, so it’s really important to remember to look for the premium grade product. Some of the lower grade products might be a little cheaper in the short run but they’re not washed in the same way that the higher grade coco is, so you can be bringing this inferior coco into your facility, it can come already charged with salts in it, and this can start to reek havoc when you start feeding your salt based nutrient formula.

In most commercial cultivation facilities that I’ve been in we’re using either three-gallon (#3) or five-gallon (#5) pots. That isn’t to say that three-gallon and five-gallon are your only choices, it’s just that most high production facilities are running optimally at that. If you start going with bigger containers, you start running into size and space constraints, and moreover, you could potentially end up with wasted media. If you were in a greenhouse I might recommend something like a twenty-gallon container, of course we’d be talking about a much longer veg cycle and we’d be talking about a much bigger plant.

If you guys want to learn more about my recommendations when it comes to media please feel free to check out the course notes.


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Course Notes:

Recommended Reading:
Soil Microbes and Fungi Improve Plant Growth


Suggested Products

Enter code GNU-Student for 10% at Growershouse.
(Excludes “Killer Deal” items)
Grodan ParGro Quick Drain Biggie 6 inch x 6 inch x 6 inch Block
Fox Farm Ocean Forest Organic Potting Mix
Canna Coco


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