With cannabis existing for much longer than we have, as growers, we can only try to replicate the conditions the plant has grown accustomed to. In nature, there are myriad factors that go into growing a healthy plant. But when we’re growing medicine for people who may need it for survival, we can’t allow nature to run freely.

Because of this, we try to control every aspect of a grow room to the point where sometimes we may go to unnecessary measures. It’s aspects like this that can be very exhausting and time-consuming, taking away from the love and fun you have growing cannabis. So today, we’ll bring back a bit of nature into your plantation, allowing it to take care of a few things for you.


Soil is made up of different layers. There are layers with more minerals, and layers with more organic material. Mulch is the very first layer. When walking around a forest, mulch is what you see on the ground all around you. It covers the soil and protects it.

There are different types of mulch, and these will work in different ways. It’s up to you to study them and judge what works best for your situation. But we’ll give you a good introduction to kick-start your research.

Mulch is great for supporting the microbial life in your soil. Green mulch is ideal for feeding your plants with necessary “healthy” bacteria. This kind of mulch is very attractive for these bacteria, consisting of primarily dead leaves and insects. This will mediate the pH of your soil in a natural way, and can improve the intake of certain nutrients in the root zone. Bacteria loves a neutral pH.

Brown mulch consists of dead plant matter like wood chippings and twigs. This type of mulch doesn’t mix as well with soil, which can actually be an advantage. Brown mulch is a very attractive environment for fungi, and fungi love a more acidic environment. Therefore, a correct mulch balance is crucial for an ideal pH.

Types of Mulch For Cannabis Cultivation


To understand how mulch works, we must first understand one crucial concept: the plant’s life cycle. During the time a plant is alive, it will intake nutrients from the soil to grow, develop, and sustain itself. The nutrients are then returned to the soil when the plant dies and decomposes. Growing cannabis with the intention of harvesting essentially removes these nutrients from the soil permanently.

So, with mulch, you’ll be returning nutrients to your soil that your plant needs. Not only that, but you’ll also be creating that essential layer that helps maintain healthy soil conditions. This extra volume of plant material will keep the soil below fresh and humid. With the mulch layer, water vapour won’t evaporate as easily. You’ll also be allowing the roots of your plant to grow closer to the surface than ever. This area that was previously avoided because it was too dry, hot, and exposed can now be fully explored by your plant’s roots.


Now that you understand what mulch can do for plants, let’s learn how to properly use it for our sweet Mary Jane. Considering how mulch affects pH, using it improperly can do more damage than good.

During the vegetative stage, green mulch will be your best option. Bringing the pH to a value of 6.7 will help boost bacterial growth. This is important for the vegetative-friendly nutrients your plant needs at this point. But don’t overdo it. A good 5cm of mulch will be enough. When moving to the flowering stage, you might want to lower the pH value. Making it more acidic at an ideal 6.4, brown mulch will improve the intake of macro and micronutrients. This is exactly what you’re looking for to get those juicy buds.

One last thing that you should be aware of is what comprises your mulch. Whether you’re making your own or buying it from a designated grow store, just know that you’ll be smoking its contents in the finished product. Stay away from treated or painted woods, as well as anything nonorganic when making your own.

Mulch and No Mulch In Cannabis Cultivation


Speaking of; there is one exception, plastic mulch. This may sound contradictory, but the use of plastic in agriculture is nothing new. It has its own name: plasticulture. You may be familiar with the use of plastic to cover greenhouses. This is a lot cheaper than glass, and can be more effective. Using a single layer of plastic can isolate heat better.

But when it comes to mulch, the plastic version is simply the concept of covering the ground surrounding plants with plastic. Similarly to a greenhouse, covering the soil with plastic allows it to retain more humidity. It does this by shielding the soil from direct sunlight and by keeping evaporated water from leaving.

Growers will use different-coloured plastics for different effects. Black plastic is the most commonly used. Its sole purpose is to retain maximum humidity. Contrary to organic mulch, as you’ve probably guessed by now, plastic mulch will not supply your soil with extra nutrients. It is not a replacement, but rather a very practical solution if your main problem is water retention. If your nutrients and pH are on point, you might not want to mess with organic material and risk messing things up.

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