With composted super soil you’d need to buy new soil every grow, or about $140 for every 15 gallons, every harvest.
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).
$35, fills 12 gallons worth of pots)
Start giving nutrients after a few weeks, for example, Dyna-Gro Grow & Bloom ($25)
Coco + Perlite Potting Mix
These plants were grown in composted Super Soil under two Electric Sky ES300 LED grow lights
Bad Cannabis Soil
Although this seedling is over a month old, it has stayed tiny. Its growth is stunted by the thick heavy soil that holds way too much water and not enough air. Note how some of the soil looks like one solid object.
The following video shows the soil texture you want (this is Coco Loco, an excellent soil for growing cannabis)
If you get the soil part right, you have almost everything you need to get to harvest! With the correct texture, drainage and water retention, you’ve got a perfect base. Add good soil cannabis nutrients, especially in the budding phase, and you should get to harvest with great results!
More About Common Amendments to Alter Texture, Drainage & Water Retention of Soil
Example of happy marijuana plants in good soil!
Important Cannabis Soil Considerations
Good Cannabis Soil
The plant is growing in organic, composted “super soil” which has enough amendments to last your entire grow, so the only thing you do is add water!
Just like humans, plants need the right nutrients. The most important ones for your cannabis plants are nitrogen (N), potassium (K) and phosphate (P). These make up the ratios you will typically see on fertilizer labels.
Test kits are available to measure your soil’s acidity, or you can take a sample to your friendly local extension agent. If your dirt does not have the proper acidity, soil amendments are available to lower or raise the pH level in your soil. Your local nursery, garden store or extension agent can make some suggestions.
Clay is just the opposite. When it’s hot and dry, clay can become hard as a rock, making it difficult for roots to penetrate. Clay drains poorly and is hard to cultivate. On the plus side, it is rich in minerals and natural nutrients.
The optimal ratio for loam is 20% clay, 40% silt and 40% sand. Most folks think a pH of 6.0 is best for cannabis, with a range of 5.8 to 6.3 being acceptable. With a pH close to neutral, loam is typically in that zone or close to it.
Loam for Growing Marijuana & Other Crops
Silt soils have lots of minerals and retain moisture well. Like clay, however, this type of soil can become compacted and hard in certain conditions. It can also form a crust, making it difficult for moisture and nutrients to reach plants’ roots.
Sand is easily permeable for root growth, for instance, but it does not hold on to water or fertilizer well.
Four basic soil types exist: sand, clay, silt, and loam. Each has its pros and cons for gardening.
Loam is ideal for containers as well as for outdoor growing. Unfortunately, it is usually the most expensive soil to buy. But if you are interested in growing the best plants possible, it can pay big dividends in the long run.
You can also build up your own loam soil by adding organic matter to it. If you have a compost bin, you can use the compost to improve your soil. This will be a time-consuming and ongoing process but with grit and persistence will pay off in the long run.
Of these types, loam is by far the best soil mix for growing marijuana plants and many other types of crops. Loam is a mixture of clay, sand, and silt, bringing forth the best qualities of these disparate types of soil while minimizing their worst attributes.