More than any medium, many growers still use gardening soil to grow cannabis plants because it's natural, cheap, low maintenance, and usually easily available. Moreover, it quickly absorbs mistakes in a more forgiving way than hydroponics.
Cannabis grows best in light and loose soils, with a good balance between water retention and drainage.
You cannot grow cannabis on every soil. Clay soils contain a lot of nutrients, but their density and weight will choke the roots of your cannabis plant.
Sandy soil is another option, but it drains too much and you may have to water constantly your plants to get good results.
Mainly two kind of soils work well for cannabis plants: silty soil and loamy soil.
Loamy Soil
Even if there's no specific soil for growing cannabis, loamy soil is highly recommended among many growers. But what makes loamy soil so special? Well, it's a combined mix of sand, silt, and clay.
Loamy soil has high water and nutrient retention levels. Aside from this, it also has an excellent drainage and aeration capabilities.
Plants can take everything they need without getting waterlogged or disturbed by issues such as root rot. Moreover loamy soil compared to others can warm up in spring months protecting the roots growth.
The only drawback of using loam is that you can’t mix them on your own. You could go for pre-mixed soil, but it's quite expensive than other types of soil.
Silty Soil
Silt soil is another option to consider for cannabis cultivation. Silt soil is rich in naturally occurring nutrients and does a great job of retaining water. It's also cheap and can be used to grow a wide range of crops aside from cannabis.
Silt usually drains well, but problems may occur when the watering is excessive. If you choose silty soil, ensure you give your plants the right amount of water to avoid drainage issues.
Can I Make My Own Soil?
Yes. You can create cannabis potting soil blends of different textures, nutrient content, density, and water-holding capacity.
Many people prefer to create their own soil for personal reasons. Either they have their own for growing cannabis, or they're trying to save money by mixing the ingredients themselves. If you have a secret formula that would give you the best soil, stick to it.
However, if you're going with the DIY method to reduce costs, you're wrong. You'll have to purchase large quantities of every nutrient and additive separately and blend everything yourself.
If you're only growing one or two plants at a time, there are better options than going the DIY route. A bag of perfectly pre-mixed soil is less expensive than one bag of unmixed ingredients like coco coir peat. DIY projects are fun, but this one might not be the best option for beginners.
If you're just starting, simply get ready-made cannabis potting soil from the grow store. This prepared soil mix contains everything your plants need to flourish.
All you have to do is replenish the nutrients on your cannabis soil every few weeks. Companies that produce potting soils often sell nutrient packs arranged to work with the soil. You have to worry about it.
What You Should Consider Before You Choose Your Soil
Soil Texture
For cannabis, the texture of your soil should be loose and lightweight. This soil texture fosters root development and guarantees oxygen circulation at the roots. As a result, it boosts the growth and overall health of the plant.
Drainage Capacity
Cannabis plants do not need to be watered 24/7. You want to make sure that the soil you're using drains easily. For cannabis growth, the soil should be moist and not soaking wet.
If your soil remains too wet, mold and bacteria will grow on the surface. In a good setting, the soil's surface should dry out between watering.
Water Retention
Just as good drainage, water retention is also necessary. Without it, you'll have sick or dying plants.
pH
The best pH level for growing cannabis in soil is between 6.3 and 6.8. The pH value of your soil will determine how fast your plants can absorb nutrients. A low-quality soil will slowly undo all of your hard work.
Nutrients
The soil you use to grow cannabis must contain the proper nutrients needed for its growth including Nitrogen, Phosphorus, Potassium, Calcium, Magnesium and Sulfur among others. Luckily, almost all soils contain these components even if generally they will last only 3-4 weeks.
By the time your plant starts to flower, most of the nutrients in your soil will have been consumed. At this point, you should begin adding nutrients to your soil.
To minimize cost, you can go for organic substances such as humus, compost worm casting and more. Microorganisms within the soil will convert these organic substances into plant nutrients.
Best Soil Additives To Improve Soil Quality
Coco Coir
This additive is made from coconut husks. These fibers help in water retention and can also lighten compact soils. To improve your soil, you can pass up to 30% coco coir, depending on your soil composition.
Perlite
Perlite is one of the most popular supplements you can use in your cannabis soil. It's made up of light, bright-white rocks. It's mainly used to improve the fairness and drainage of the soil. You can add 10-15% of perlite for soil improvement.
Vermiculite
This additive is similar to perlite but it is used for water retention. It's a heat-treated mineral that you can use to make your soil lighter. Adding 10% of vermiculite would be enough for your soil.
Worm castings
Worm castings are excellent soil amendments that improve your soil's quality and nutritional properties. They help improve your soil's texture, drainage and water-holding capacity. For soil improvement, use about 25-30%.
Clay Pebbles
You can use clay pebbles to enhance your soil structure. Adding them at the bottom of the soil helps with drainage. It also prevents water from resting at the base. It can also be used as mulch to help trap moisture.
