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Learn the top techniques for growing cannabis in peat moss.

Most cannabis cultivators have their favorite methods of growing, as well as their favorite grow media and nutrients. The two main schools of cultivation are hydroponics and soil (biological) growing.

Both methods of growing can benefit from grow amendments such as peat moss. This type of media can significantly improve the root structure that can be the foundation for a healthy cannabis plant.

Our guide on techniques for growing cannabis with peat moss breaks down the advantages and disadvantages of using peat moss, as well as techniques on how to properly use this media as your soil amendment.

Hydroponic Growing

Hydroponics is a method of growing without traditional soil that uses nutrient-rich water and an inert growing medium, like peat moss mixed with other media such as perlite to improve its aeration. The plants are suspended in gravel, water, sand, rock wool, clay pellets, or other material, and the root systems are fed directly with a nutrient-rich water solution.

Although it sounds fairly hi-tech, hydroponic growing is nothing new, and it has a fairly long history with cannabis-growing. The practice goes back centuries, with some botany historians identifying hydroponic practices with ancient cultures in many different regions of the world.

Hydroponic growers swear by this method—just like soil growers are incredibly devoted to their traditional cultivation method. Even within the schools of hydroponic and soil grows, there are a variety of methods, media, and nutrient recipes.

Soil Growing

In this article, we’ll focus on one of the lesser-utilized soil mediums: peat moss. A good cannabis soil mixture can contain any number of substances that, when combined, create a good soil mixture to help with water retention and nutrient absorption.

Because there is such a wide variety of potentially good ingredients to put into a soil mixture, the possibilities and various ratios of ingredients depend on your unique garden needs. Among the various suitable soil ingredients are potting soil, compost, perlite, coarse sand, coco coir, fine gravel, and peat moss.

What Is Peat Moss?

Peat moss, in particular, is a beneficial element to any indoor or outdoor cannabis garden. Also known as sphagnum moss, peat moss belongs to a family of hundreds of moss species that grow in wetland areas, known as peat bogs. For horticultural uses, peat moss is made up of the decomposed matter of different types of moss.

When cultivating with cannabis, peat moss can help provide two important things to any garden: aeration and moisture.

The root systems of plants are just as important as what grows above the soil surface, yet some growers tend to neglect it more, in a variety of ways. Inappropriately designed pots, pots of the wrong size, and water and nutrient inadequacies (too much or too little) being just a few of them.

Roots are the foundation for this time and foliage that grow from it. A strong root system is critical to withstand the environmental challenges above the soil such as rain and wind. Roots also help absorb water and nutrients from the soil.

Root systems must stay moist to remain healthy, and plants do not grow nearly as well when their roots are cramped in a confined space. Well-aerated soil helps them spread out and grow, which is why a relatively loose soil mixture that allows easy root growth and nutrient intake is superior to dense soils that contain too much clay.

If you've ever purchased a bag of soil mixture, it is likely to have contained peat moss as an ingredient. In cannabis, peat moss can be a valuable addition as a soil amendment but requires careful preparation and maintenance to yield positive results.

Why Is Peat Moss Soil Good?

Water Retention

Peat moss is a great soil component for its ability to retain water (up to 20 times its weight) and hydrate plants over an extended period of time. If you live in a dry climate, peat moss can do wonders to save you water, and the frequency of watering, as well as preventing plants from becoming too dry.

Perlite can provide aeration in any growing set-up to prevent damp moss which can lead to mold.


Peat moss also provides some valuable micronutrients to the soil. When used alongside fertilizers and other nutrient-rich substances, peat moss can hold on to a large number of nutrients and make them available for absorption by the plant’s roots. It also contains a range of elements, such as sulfur, which helps plants express their terpenes for better smelling buds.


As a relatively sterile type of media, peat moss is free of weed seeds, pests, and pathogens. This is ideal for young plants that may be vulnerable to contaminants. More importantly, this soil amendment can produce a growing environment with beneficial fungi and bacteria that lead to a healthy crop.

Acidic pH

Peat moss pH is slightly acidic, so it allows for the use of alkaline soil amendments. In soils that are too alkaline, peat moss is often added to balance the pH. The management of pH is critical in the absorption of nutrients in plants. A pH level that is outside the recommended range can lead to nutrient deficiencies.

Despite these advantages, peat moss often gets overlooked in favor of other popular soil amendment ingredients, which is unfortunate.

Drawbacks of Using Peat Moss

On the other hand, peat moss has a few disadvantages when growing in soil-based or hydroponic set-ups that must be considered. From its preparation time to its unsustainable sourcing, it is important to consider these factors when deciding what ingredients to use in your cannabis grow media.

Structural Issues

When used alone, peat moss mixtures can literally cave in on themselves under pressure when wet. In large and heavy containers, peat moss can compress, which can lead to anaerobic conditions in the mixture. This means your soil will have very little oxygen for its roots and can develop a pungent ammonia smell.

Preparation Time

In addition, using peat moss is not as easy as mixing it into your growing container and forgetting about it. Growers must undergo a weeks-long preparation process to get the moss ready to provide the right structure and nutrients for your plant’s roots.

pH Levels

Peat moss can be high maintenance in terms of managing its pH levels. By itself, it has a low ph. Many growers choose to regulate the pH with lime, but the pH levels can still slowly get lower, so you will need to regularly check your mixture.


If you're an eco-conscious grower, peat moss may not be the best soil amendment to use. Peat moss can come from a variety of materials, but much of the peat moss sold for gardening comes from Canadian sphagnum moss.

Peat refers to the decomposed matter of the sphagnum moss and is mined from peat bogs, also known as peatland. It is believed that peat mining companies are doing a huge part in destroying these vulnerable ecosystems. Harvesting this moss can threaten wildlife and native plants found along the peat bogland, which can lead to other negative environmental impacts.

Techniques for Growing Cannabis in Peat Moss

Preparing peat moss for use in your cannabis garden is pretty straightforward but can take many weeks of preparation. Make sure to take into account this prep time when planning your cannabis planting.

Because peat moss is initially resistant to absorbing water and repels it, also known as being hydrophobic, the first step is to prepare it for soil use. This is best done during the spring months when the days are growing warmer and longer.

Prepare the peat moss for later use by placing a substantial amount of peat moss in a large pan or deep containerand thoroughly moistening it with water. Spread the peat moss out to cover the bottom of the pan to increase the surface area, and leave it outside for a few weeks. This will allow the peat moss to soften and become more absorbent, as well as allow it to grow important micronutrients.

You want it to get exposed to rain and morning dew as much as possible, but if water collects in the pan, pour it out so it doesn’t get stagnant. If you live in an arid region, be sure to periodically spray the peat moss with water.

Coarse, clumpy chunks of peat moss work better for soil mixtures than thin, wispy peat moss. Remember that peat moss must be kept evenly moist in order for plants to grow their best. Avoid letting it dry out because it will once again be resistant to absorbing water and will require attention and treatment.

After a few weeks, assemble the peat moss with equal parts of a good-quality potting soil or garden soil that does not contain any fertilizers. Some commercial soil mixes have synthetic fertilizers added, but to grow good-tasting cannabis, you want to grow organically and avoid synthetic additives.

Also purchase an equal part of perlite, which will help increase the soil aeration and aid root development. If you do not have access to perlite, you can substitute it with thick, coarse sand. Avoid any sand with tiny grains.

To mix the soil, combine equal parts of the peat moss, soil, and perlite into a large garden bucket and thoroughly mix the ingredients together with your hands and a hand spade. You want the three ingredients to be evenly distributed throughout the mixture. To do this, you will want to add a nutrient-rich ingredient like compost (you can easily make your own at home) or a commercially available product like Big Bloom.

Compost is a valuable ingredient when growing organic cannabis because it feeds the soil. Big Bloom, used in combination with Grow Big and Tiger Bloom, is an almost purely organic mixture that feeds the plants rather than the soil. So, while compost will feed the peat moss soil mixture, compost will feed the soil. In the correct ratios, they work well together.

Your cannabis plants will grow very well in a peat moss soil mixture right from the start. After the first couple of weeks, supplementing it with the Big Bloom and Grow Big nutrient (follow the feeding schedule provided for the trio) will ensure your cannabis thrives throughout all stages of its life cycle (vegetative, flowering, and pre-harvest).

Peat Moss vs. Coco Coir

Since they have a similar consistency, many soil mixes contain either peat moss or coco coir. Both can work well and have their own unique benefits and drawbacks. Most cannabis cultivators have a preference for one or the other.

Coco Coir Benefits

Although similar to peat moss in its consistency, coco coir has its own unique sets of benefits that differentiateone from the other. One of the unique benefits of coco coir is that its pH typically runs between 6 to 6.7, which is perfect for cannabis.

Since coco coir is harvested from coconuts, it is a renewable resource—unlike peat moss. It also absorbs water much easier and is much easier to rehydrate if it gets overly dry. It has excellent water retention properties, retaining 8to 30 times its own weight.

Like peat moss, coco coir is an outstanding habitat for microorganisms.It is also free of pests, pathogens, and weed seeds. Coco coir is durable and due to its lignin content, it breaks down slower than peat moss. Finally, coco coir is typically less expensive than peat moss—and this lower cost is something that everyone can appreciate.

Coco Coir Drawbacks

Coco coir also has some drawbacks. It has a high salinity unless thoroughly washed, and its quality and consistency can vary more than peat moss, depending on the source. It also doesn’t contain many microorganisms and few trace elements.

Also, because some coco coir is sprayed with pesticides in its country of origin, combined with its tendency to be high in sodium and magnesium, means that it must be thoroughly washed and treated (follow the same instructions for treating coco coir as the peat moss method detailed above).

Which One Should You Use?

Because peat moss and coco coir have several similarities as well as differences, it is easy to see why both have their legions of devotees. There are really no right or wrong answers when it comes to using one or the other; it is just a matter of personal preference.

Since it is used less often than coco coir for cannabis cultivation and has many benefits, do not overlook peat moss the next time you plan a cannabis soil mixture. Most likely, you will be happy with the results and use it as a regular soil ingredient.

Growing Cannabis in Peat Moss FAQ's

What are the benefits of using peat moss for growing cannabis?

Cannabis plants benefit from peat moss' water retention, aeration, and slightly acidic pH. A generally sterile soil reduces soil-borne illness risk.

Is peat moss alone enough for growing cannabis, or do I need to mix it with other substances?

Peat moss can be used alone, but it's usually blended with perlite, vermiculite, or compost to promote drainage and nutrients. Peat moss and perlite are often mixed 70:30.

Does cannabis grown in peat moss require additional nutrients?

Peat moss is low in nutrients, so you'll need a cannabis-friendly nutrition solution. Include vital micronutrients and macronutrients including nitrogen, phosphorus, and potassium.

How does the pH of peat moss affect cannabis growth?

Peat moss is acidic (4.0–6.0). Using peat moss may require adjusting the pH of your water or nutrient solution to 6.0–7.0, as cannabis plants like this range.

Is peat moss environmentally sustainable for cannabis cultivation?

The sustainability of peat moss is disputed. Peat bogs take centuries to form, therefore harvesting peat moss can harm the environment. Use sustainable alternatives or responsibly sourced peat moss.

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How often should I water cannabis plants in peat moss?

Plant size and environment affect watering frequency. Do not overwater peat moss since it holds moisture. Peat moss wetness should be checked before irrigation.

What are some alternatives to peat moss for growing cannabis?

Coco coir, compost, and cannabis-specific soil mixtures are alternatives. Each media has advantages and disadvantages.

How do I manage pests and diseases in peat moss cannabis grows?

Clean the growth area, check your plants, and employ organic insect control if needed. Peat moss's sterility reduces soil-borne illnesses.

Can peat moss be used for both indoor and outdoor cannabis grows?

Yes, cannabis grows well indoors and outdoors with peat moss. Outdoor producers must also consider their climate and pests when using peat moss to grow cannabis.

Become a Cannabis Growing Expert with CTU

Now that you know the basics of using peat moss to create beneficial soil for your plants, you can learn how to use other grow media to find out which works best for you.

Learn about all the latest cultivation methods from industry professionals when enrolling in Cannabis Training University’s online marijuana classes.

Whether it is your first time growing or you are a seasoned grower, CTU has a complete curriculum that takes you through every step of the cultivation process.

Learn about the fundamentals of growing cannabis and advanced growing techniques to maximize the quality of your harvest. Start your journey toward becoming a master grower today!

Luis Cordova
Luis Cordova

Luis Cordova is a distinguished author, and renowned expert in cannabis cultivation, who possesses a Master's degree in Plant Biotechnology and Pharmaceutical Science. As a valued contributor to highly esteemed publications such as Cannabis Training University and Maximum Yield Magazine, Luis has emerged as a trusted source of guidance and knowledge in the cannabis industry. Having written thousands of informative articles, Luis is widely recognized for his comprehensive expertise on cultivating cannabis, both indoors and outdoors.

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