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Mulching on Cannabis Plants: How And Why You Need To Do It

Added 5 September 2023

In layperson's terms, mulching is covering the soil with something like sawdust, grass cuttings, or dead leaves. But there’s more to this easy process than meets the eye. 

Many growers ignore mulching as they don’t understand how covering the soil with some grass clippings or newspapers can do any good. However, mulching offers a lot of benefits, and you certainly shouldn’t ignore them. 

For example, did you know that mulching reduces the need for watering frequently? This is because it serves as a barrier that prevents too much evaporation. Mulching also regulates the temperature of the soil, ultimately resulting in robust root systems. 

But, before you start mulching away, know that there are some nuances you must keep in mind, including the type of mulch to use and its benefits, how to apply it, and more. 

Learn all about mulching for cannabis plants in this article. 

What is Mulching While Growing Cannabis?

What is Mulching While Growing Cannabis?

Image Credit - no_average

Mulching is a very old farming technique that has found its way into cannabis gardens due to its benefits. Essentially, mulching is the process of applying a layer of mulch on the soil. You can use several materials like old leaves, bark, and paper as mulch. 

The technique seems surprisingly simple, doesn’t it? All you have to do is layer the soil with organic material or inorganic mulch, but regardless of what you use, the mulch serves a few basic functions, such as the following:

  • Protecting the soil from environmental stressors 
  • Trapping moisture within the plant 
  • Providing a food source for the microbes in the soil 
  • Insulating the soil, etc. 

In the natural world, like a forest, the ground is usually covered by various things, like grass, small plants, and living and dead organic matter. So, even out in nature, the soil is usually never bare. This is what you have to replicate in your cannabis garden by adding mulch — your cannabis plant has evolved to grow in a cozy environment. 

What are the Benefits of Using Mulch for Cannabis?

What are the Benefits of Using Mulch for Cannabis?

Mulching is a terrific growing method that can improve your cannabis operation significantly, and perhaps the best thing about it is how easy it is to do, even for beginners, considering the outcomes. But what are the outcomes? Here are some of the benefits of mulching for cannabis.

1. Mulching Protects the Soil and Roots

One of the biggest benefits of mulching for cannabis is that it protects the soil and roots from environmental stressors in various ways. For starters, mulch helps maintain consistent temperatures in the rhizosphere. Temperature is one of the primary factors that lead to better plant growth, and mulching minimizes temperature fluctuations in the soil by keeping the ground from heating up when it is too hot and trapping the heat when it gets cold. 

Another way in which mulching protects the soil is by preventing erosion and compression of the soil. These problems occur during showers or even regular irrigation. If you don’t take care of them on time, the soil may erode away and expose the roots to the environment — that’s not a good thing as the soil will also lose its drainage and aeration capabilities. So, mulching protects the soil from this. 

2. Retains Moisture Within the Soil 

If you want to perfect your watering routine, mulching can come in quite handy. Mulching retains moisture within the soil, improving the ground’s water retention, so you don’t have to water your plant so frequently. This is a fantastic benefit if you are growing your cannabis plant in a hot, sunny region where the soil can dry out too quickly. 

Additionally, this advantage further benefits your soil: mulch insulates the soil, keeping it cool for longer. You also end up saving a lot more water as it can retain up to 70% of the water within the soil, thereby reducing your garden’s water consumption significantly. 

3. Improves Soil Quality 

If you choose organic mulch, it can even improve the quality of your garden soil. Organic matter is made up of mostly dead plant matter, which breaks down over time after being applied to the soil. During the breakdown process, they release nutrients gradually into the soil, which can help your plant flourish. 

If you use the mulch correctly, it can take care of feeding your plants entirely, so you don’t have to feed your plants as much. This makes mulching one of the easiest ways of feeding cannabis plants and improving the quality of soil. However, this may not be an ideal solution for cannabis plants that need nutrients quickly. 

Another benefit of mulch is that, by breaking down, it encourages the growth of beneficial bacteria within the soil that are protected from harmful environmental factors like heat. These beneficial bacteria not only fix nutrients for the roots but also protect your plant from harmful pathogens and pests that may otherwise end up harming your plant. 

4. Reduces the Risk of Pests and Pathogens 

On the same lines, mulch prevents harmful pathogens and pests from making their way into the soil by acting as a barrier between the environment and the ground. Plus, a healthy and rich living soil is not a thriving environment for such pests and pathogens. These advantages combine to protect your plant from various infestations and diseases in the long run. 

5. Prevents Weeds 

Weeds (not the cannabis ones) can be a nuisance when growing outdoors; they steal nutrients from your plant, hamper root development, and invite pests and pathogens into your garden. So, by adding mulch, you can significantly reduce the chances of weeds growing in your garden. 

And even if weeds grow in the mulch, you can easily pull them out — making the weeding process much easier and less harmful to the soil. If the mulch wasn’t there, the weeds would grow directly in the soil, making it much harder to pull and damaging the soil. 

What Are the Types of Mulch for Cannabis Plants?

What Are the Types of Mulch for Cannabis Plants?

Whether you are growing cannabis or tomatoes, mulch comes in two types: organic and inorganic mulches. Which one is better, and which one should you choose, let’s take a look at the two types of mulches for cannabis plants and a few examples of the same. 

Organic Mulch for Cannabis Plants

Organic mulch, as the name suggests, is made from organic matter that decomposes over time. During this decomposing process, this mulch will release various nutrients and compounds that nourish your cannabis plant while improving the soil structure and drainage. 

These mulches are also excellent for improving the quality of your soil as they encourage healthy bacteria and fungi growth in the soil, which helps decompose the organic matter while protecting your cannabis plant against harmful pathogens and pests. 

Organic mulch comes in various varieties, but a rule of thumb to remember is that a dryer mulch will decompose slower while releasing fewer nutrients compared to a wetter variety of mulch. So, depending on your preferences, choose a mulch that suits your plant’s growing period. 

Lastly, organic mulches are always eco-friendly and cheap to get your hands on. If you’re smart about it, you can prepare your own mulch by recycling organic matter from your garden and kitchen. This is the go-to option for growers who want to cultivate cannabis in the most eco-friendly way possible.

Here are some of the most popular organic mulch options for cannabis plants.

1. Bark and Wood Chips 

Bark and wood ships are dry, woody mulches that are known for their long breakdown/decomposing time. However, due to this, they tend to release nutrients slowly into the soil. On the bright side, you don’t need to replace these woody mulches often so they can last a very long time if nutrients aren’t your first priority for using mulches. 

Bark and wood chips are excellent mulches for improving your soil’s aeration, moisture retention, and structure. And they can also protect your soil from the environment since they are harder to get through. If you’re worried about bark and wood chips not offering enough nutrients, you can always pair them with a wetter type of mulch!

2. Grass Clippings 

On the other hand, a terrific example of wet mulch is grass clippings or cut crass, along with other plant matter from your garden, which can be quite beneficial for your cannabis plant and soil. 

Since grass clippings are wetter, they will break down faster, providing useful nutrients to your cannabis plant. Pro tip: Use dead cannabis plant matter since it contains all the nutrients your plant will need, anyway. 

Grass cuttings are also almost always free, and they go a long way in protecting your garden soil from erosion while improving its moisture retention capabilities. Consider grass cuttings or other plant matter if you’re short on cash and want something basic but useful. 

3. Dry Leaves

Dry leaves work in a similar way to grass cuttings but it is much dryer, so it can last a lot longer. Dry leaves are also perhaps the best way to replicate a natural outdoor environment in your garden, as they are the default mulch for forests. 

Dry leaves enhance soil structure and improve aeration and drainage, and they are rich in nutrients for cannabis plants. Plus, it’s not difficult to find dry leaves, especially if you live near a forest. Simply pick up fallen leaves around your house during autumn and cover your soil with them; they will last an entire growing season. 

4. Straw

Straw mulch is an effective mulch that is known for its insulating properties, especially in colder regions. This mulch traps heat within the soil, protecting the roots from cold stress, and it can also come in handy during warm weather to keep the soil cool, especially after irrigation. 

Another benefit of using straw as mulch for cannabis plants is that it protects your cannabis plant from soil-borne pathogens and pests. It creates a healthy environment for beneficial insects like spiders that prevent harmful pests and pathogens from making their way into your cannabis garden soil. 

5. Seaweed or Kelp

Seaweed or kelp is one of the best fertilizers for cannabis plants, and what do you know, it’s also one of the best mulches! You can buy this product from a horticultural store in the form of pellets or powders, but you can also get your hands on raw kelp to use as mulch. You can even harvest kelp on your own as long as it's legal in your state. 

Kelp is wet and rich in nutrients, so not only will it act as a fertilizer for your cannabis plant, but it also protects the soil from the environment, especially temperature fluctuations. The only downside is that you may have to replace this mulch regularly, depending on the type of kelp product you use. 

6. Pine Needles

Pine needles or straws are excellent mulches for soil that’s too alkaline, as they can lower the pH of the soil by a smidge. But you can still add it to neutral soil but keep an eye on the pH in the first few days to ensure it doesn’t get too acidic — it likely won’t, but it’s better to be safe than sorry. 

This mulch is also good if you want to protect your soil from getting compacted over time and improve its moisture retention ability. It’s recommended that you use slightly dried pine needles or use them with other mulches for the best results.

Inorganic Mulches 

Inorganic mulches are made from synthetic materials like geotextiles, fabrics, and plastics. These mulches, depending on which one you choose, offer similar benefits to organic mulches in terms of protecting the soil from erosion and the environment, insulating it, helping it retain moisture, and preventing some harmful pests and pathogens. 

On the flip side, inorganic mulches do not release any nutrients, so they cannot help fertilize the soil or improve the soil quality. Since these are synthetic in nature, some types of inorganic mulches can be bad for the environment, which is a factor to keep in mind when growing organic cannabis. 

We won’t go into much detail about inorganic mulches since they aren’t so popular in cannabis gardens. Still, you can consider them if you think you can utilize them better than organic mulches. Here are some examples. 

1. Silver or Black Plastic Mulch

Two of the most common types of inorganic mulch are black and silver plastic mulches, which are terrific at keeping the soil warm in colder climates while improving water retention in the soil. Plus, they are very easy to use and can last a long time. 

The downside with plastic mulch is that it’s not permeable, so it may be difficult to water your plant after applying it to your cannabis plant. And depending on the manufacturer, it can sometimes break down and leach plastic into the soil. Lastly, it is not eco-friendly. 

If you live in a warmer climate, it’s recommended to avoid black or silver plastic mulch as it can heat the soil during the day, which can lead to heat stress in your cannabis plants. 

2. Stone, Gravel, or Brick Chips 

If you’re looking for a permanent solution, consider using stone, gravel, or bricks in your cannabis garden. Yes, these products are expensive to apply, and moving them is difficult, but they offer adequate protection to the roots while decreasing the risk of weeds, pests, and pathogens.

3. Fabrics

The third type of inorganic mulch is landscape fabric, which prevents weeds while improving air and water retention within the soil. They also don’t break down so fast, and depending on the manufacturer, they can be eco-friendly in nature. If you are looking for long-term, inorganic mulch, nothing beats fabric mats. 

How and When to Apply Mulch in Your Cannabis Garden?

How and When to Apply Mulch in Your Cannabis Garden?

Mulching your cannabis garden is relatively simple, but it may seem a bit tedious for some growers. But with the right steps, even a new grower can successfully apply mulch. Let’s take a look at how you can use or apply mulch to your cannabis garden below. 

Get Your Hands on the Mulch 

The first step is to get some mulch. You can either buy it from a gardening store or make your own. Purchasing it may be expensive, but if you want a particular type of mulch that’s available in the market, go for it. For most growers, making DIY mulch is the way to go. 

Making mulch is easy as it is almost free, and Mother Nature offers a lot of options. You can use your old newspapers, fallen leaves, cut grass, dead plant matter, and so much more to prepare your mulch. If you are purchasing mulch, ensure it is multi-purpose and suitable for topsoil application. 

1. Start Applying the Mulch in Spring for Regular Mulching 

If you are an experienced cannabis grower or using live soil as a new grower, you’ll want to apply mulch to the soil when the weather picks up. So, during springtime, start applying 10 cm of coarse mulch of your choice before planting your cannabis seedlings. Doing so during this month will help retain moisture and keep the soil cool during the summer months. 

When transplanting the seedlings into the soil, all you need to do is pull back the mulch and transplant the seedlings gently into the holes in the soil. Then, push back the mulch to cover the soil properly around the plant’s stem. 

2. Use Compost Before Mulch to Restore Your Soil 

On the other hand, if you want to restore your soil back to its richness, you’ll have to take the long way around to mulching. For this, cover the soil with 2 to 3 cm of compost or worm casting before you start applying the mulch in spring. After applying the compost, cover the soil with 10 cm of mulch and let the compost disperse into the soil for a week before planting your cannabis plants. 

For the best results, reapply compost followed by mulch during autumn and spring to ensure your soil stays healthy and rich. 

3. Using Mulch Indoors 

If you’re an indoor grower, you can even use mulch to insulate your plant’s roots by keeping them warm and cold during the winter and summer months, respectively. Like outdoor soil, all you have to do is cover the soil of your indoor plant right before the seedling phase; just don’t let the stem make contact with the mulch. 

Some Tips to Keep in Mind 

As you can see, applying mulch is super easy, but there are still some things you must keep in mind when applying mulch to your cannabis garden beds. Here are some tips to keep in mind. 

  • Do not apply too much mulch. For the best results, apply only a couple of inches of mulch; if you apply more, it can suffocate the plants or stop the water and oxygen from reaching the plants. 
  • Avoid the mulch from touching the base or stems of your plants, as it can lead to rot, gnawing rodents, and wood-boring insects. Ideally, the mulch should be at least five inches from the stem; you can even use cut plastic bottles to keep the mulch away from the stem. 
  • If your soil is not rich in nitrogen, avoid using light-colored woody mulches, as they can steal nitrogen during decomposition. And if you do use woody mulches, supplement your cannabis plant with a nitrogen-rich fertilizer to counter the nitrogen deficit
  • If you rely on fertilizers, consider using organic mulch that breaks down early; they are excellent nutrient fixers and can reduce your reliance on fertilizers for growing cannabis. 
  • Use as much organic mulch as possible, and always recycle the dead organic matter from your garden and kitchen for mulch. This will not only give your cannabis plants the nutrients they need but also make the entire process a whole lot cheaper for you.

Summary: Mulching on Cannabis Plants: How And Why You Need To Do It

Mulching is a terrific method that can significantly improve the soil quality of your cannabis garden while protecting the roots from environmental stressors like cold, heat, pests, and pathogens. So, if you want to get the best results from your plants, consider using mulch in your garden. 

The best type of mulch you can use is organic, like wood chips, dead leaves, grass cuttings, and kelp, but don’t hesitate to use inorganic mulch, like fabrics, if your preferences allow it. Start applying the mulch in spring right before transplanting the seedlings, and make sure the stems don’t touch the mulch.

To know more nifty tricks on growing cannabis plants, stay tuned to our blog. We post regular content on how to improve your cannabis cultivation.