What’s the Cheapest Grow Medium for Cannabis?

by Nebula Haze

Let’s talk grow medium costs. A cannabis grower on a budget has a lot to consider. I hope this helps clear some things up!

A lot of times you’ll hear comparisons between grow mediums for cannabis that talk about bud quality. I’ve often heard that soil produces the smelliest weed. But growers rarely talk about costs.

As far as the cost of electricity when growing cannabis, how much money is actually going to come out of your wallet during the grow?

It’s true your grow medium makes a difference in your results. If you get a bad grow medium that provides the wrong nutrients or doesn’t drain well, your plant will run into problems. The grow medium also affects how likely you get bugs (more likely in soil) and how fast plants grow (faster in coco and hydro). The grow experience is different between them (soil vs hydro are two very different growing experiences!).

But your grow medium does not make nearly as much a difference as most growers think when it comes to actual bud quality. It’s more important to ensure your plants get the nutrients they need, have a great grow light and live in a good growing environment (especially when buds are forming). These all have a much bigger impact on your final bud quality than the specific grow medium. That’s why I recommend new growers also consider costs and personal preferences when choosing the grow medium.

Composted Super Soil – “Just Add Water”

These plants were grown in composted Super Soil under two Electric Sky ES300 LED grow lights

Six cannabis plants growing under two ES300 LED grow lights by Electric Sky We only gave plain water from seed to harvest. Nature did everything else!

Six cannabis plants flowering under 2 x Electric Sky 300 LED grow lights

The “just add water” method with composted super soil is simple and produces great weed with almost no effort. However, unless you compost your own soil it costs significantly more than almost any other grow media for cannabis. In order to get 15 gallons of grow medium (for example three 5-gallon pots), you need 15 lbs of Super soil ($105), which would fill the pots 1/4 to 1/3 way. Then fill the rest of the way with Coco Loco ($31 per bag). At that point, you’ve paid almost $140 for about 15 gallons of grow medium. A wonderful and easy way to grow, but not necessarily the most economical.

With composted super soil you’d need to buy new soil every grow, or about $140 for every 15 gallons, every harvest.

“Regular” Soil

For a reduced cost, you could use a typical pre-made soil-based mix (something like Coco Loco or Fox Farm Ocean Forest soil is awesome for growing cannabis) and start adding soil nutrients once plants start using up what’s in the soil. That’s sort of halfway between a super soil and a coco grow (next).

Buy Coco Loco or Coco Loco or Fox Farm Ocean Forest soil (~$35, fills 12 gallons worth of pots)

Start giving nutrients after a few weeks, for example, Dyna-Gro Grow & Bloom ($25)

That means you pay $60 for the first 12 gallons of grow medium plus nutrients, but you’ll have extra nutrients at the end. That means for future grows you’ll only need to pay for soil until you use the nutrients up.

Coco + Perlite Potting Mix

Coco coir is made of ground-up coconut husks, and perlite is made out of expanded volcanic glass. Coco feels sort of like a really rich soil, while perlite looks like little white airy rocks, almost like popcorn. When these two are mixed together, it provides an incredible root environment for your cannabis plants. Roots tend to be healthier, plants grow quickly, you won’t get bugs, and overall your garden will be more resistant to heat or stress.

Coco + Perlite is a great potting mix for growing cannabis

If you look at the coco coir in this pictures, you can see it's starting to light up. The plant is ready to be watered.

These cannabis plants were grown in a Coco + Perlite mix.

One $35 bag of Coco + Perlite mix is enough to fill 16 gallons worth of pots (the entire tent above, which had 8 x 2-gallon pots). The big investment with coco as a grow medium is nutrients, but they’ll last multiple grows. Great nutrients for coco are Flora trio ($35) at half strength + Calimagic ($17) at 1 tsp/gallon. That means for about $90 you have 16 gallons worth of growing medium plus tons of leftover nutrients. You would only need to buy the Coco + Perlite mix ($35 for 16-gallons of grow medium) for the next several grows while you used up the nutrients (the nutrients listed last 2+ years before going bad).

Hydroponics

If you want to basically cut grow medium costs altogether, you could use a hydroponic setup. Once you’ve got your tub set up, you basically only need water and nutrients each new grow. A hydroponic tub can be put together for under $100 and basically your main cost will only be electricity and nutrients after that.

Example of happy cannabis plants in a hydroponic DWC reservoir

So which grow medium is the cheapest?

In conclusion…

  • Soil & Coco: Coco mixes are often a little cheaper, but overall soil and coco have similar costs. Nutrients are necessary for great results, especially with coco. After the first grow, costs tend to go down because you don’t have to re-buy nutrients every time. I love coco for first-time growers because plants tend to grow faster, are more resistant to problems, and are less likely to get bugs than in soil. However, soil is also an excellent way to grow cannabis, and the nice thing is you don’t need to start using nutrients until a few weeks into the grow (with coco you use nutrients from the beginning).
  • Super Soil: One of the most expensive growing media to buy. Unless you start composting your own soil, costs don’t really go down over time since you always have to buy everything from scratch every grow. However, no extra nutrients are needed, which can save money if you’re currently using expensive nutrients. An incredibly simple grow style (“just add water” from seed to harvest) but plants tend to grow slower because the roots have to seek out and break down the nutrients in the soil, as opposed to getting them delivered in the water.
  • Hydroponics: Doesn’t require a grow medium besides water. That makes it an economical choice after the initial setup since the only thing to get are nutrients once your tub is set up.
  • Nutrients: The type of nutrients you use can greatly add to or take away from the cost. These conclusions are based on the cannabis-friendly nutrients listed in the article, which are relatively inexpensive. But depending on the brand, a grower could spend hundreds (or even thousands) of dollars on nutrients and supplements each grow. If you’re using an expensive nutrient line, that can cost more than any grow medium. In that case, your nutrients will be the main cost to pay attention to.

Which grow medium should I get?

Example of a seedling growing in super soil

 

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