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How to Grow Cannabis Using Coco Coir

Coco coir in a plastic pot

Coco coir growing is an alternative cannabis cultivation style. Coco coir is a soilless substrate used in various types of gardening. Unlike Rockwool, this organic substrate offers a happy medium between soil and hydroponics and can be re-used season after season.

Coco coir is ideal for gardening as it’s easy to implement and produces large, healthy plants, including cannabis plants.

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What Is Coco Coir Cannabis?

Coco coir is a recycled natural fiber from coconut husks, primarily in Sri Lanka and India. It’s available in loose and bricked forms from gardening stores and is a magnificent grow medium for marijuana.

Cultivators can use coconut coir to amend or replace soil. Either option offers excellent aeration and drainage capacities, raising your harvest potential.

Types of Coco Coir Cannabis Growing

You may use coco coir on its own or combine it with other substances. Here are some common ways to utilize it for cannabis cultivation:

  • Pure coco coir: This medium is perfect for supporting crops grown hydroponically. Alternatively, pack pots with it and follow the classic soil-growing approach.
  • Coco-perlite mixes: Combining coco coir with perlite (usually a 3:1 ratio) further improves aeration and drainage. Since perlite doesn’t decompose, the risk of plant disease is even lower.
  • Coco-soil mixes: Coir loosens thick substrates and increases water retention as a soil amendment. These mixes are suitable for newbies and pair perfectly with beginner-friendly strains.

Advantages and Disadvantages

There are more than a few reasons why cannabis growers love working with this natural medium. Here are some of the main benefits of coco coir growing:

  • Straightforward system: Soil growers feel at home with coconut coir. The concept is essentially the same: plant crops in pots and shower them with nutrient-rich water.
  • Larger plants: This medium gives your plant’s root zone easy access to water, minerals, and oxygen, encouraging increased growth rates.
  • Shorter vegetative stage: Coco-grown plants have extensive roots stimulating more vigorous growth. Because of this, crops don’t need to spend as much time in the vegetative phase.
  • Sustainable cultivation: A by-product of coconut production, coco coir is a renewable resource that lasts for several growing seasons.
  • Adaptable to hydroponic and soil grows: Another great advantage of coco is you can run it in a hydroponic system with salt-based nutrients. Unlike Rockwool, you can topdress it with organics. You can also mix coco coir with soil if you want an organic medium that doesn’t require as many nutrients.

Now on to the disadvantages. Here are the challenges cannabis growers face using coir fibers:

  • Extra prep work: Coco coir bricks require rehydration, which tacks on extra time.
  • May attract pests: It’s sometimes advertised as pest-resistant, but coco is notorious for pest infestations at the point of purchase. Since there is less biodiversity in the substrate, it can lead to a larger bloom of unwanted pests — particularly fungus gnats.
  • Complex fertilization requirements: Coir is an inert growing medium with no inherent nutritional value. This means you must manage minerals from day one or opt for a coco-soil mix.
  • Cal-Mag shortages: Cannabis plants grown in coco coir need additional nutrients, particularly calcium and magnesium.

What You Need to Get Started

Coco coir growing requires similar equipment to soil farms. This growing medium works in controlled setups and outdoor marijuana gardens. Plus, added costs are minimal: bricks are under $50, and Cal-Mag supplements average $20. Here’s what else you need:

Coco Coir

Of course, the first ingredient you need is coir. You can buy it in three forms:

  • Coco pith: Similar to peat moss; excellent water retention but low drainage.
  • Coco chips: Larger, water-retaining chunks with air pockets; ideal for hydroponic setups.
  • Coco fiber: Stringy bundles with optimal aeration and drainage; low moisture retention.

Tip: Mix all three types to create a super-substrate. Many coco coir products come in sacks that look identical to the soil, with perlite and some organic material mixed in.


Purchase containers in varying sizes to accommodate your swiftly-growing plants. Ideally, have one-gallon, three-gallon, and five-gallon buckets for each plant. Some sativa strains need a seven-gallon pot. Choose fabric pots instead of plastic to head off moisture issues.

Water and Nutrients

Tap water is acceptable for coco coir growing. There are also nutrient lines specifically designed for hard (tap) water; for most growers, it should at least be de-chlorinated but preferably purified through reverse osmosis (a type of water treatment process that removes contaminants from water). Since you’ll need to feed regularly and maintain a steady pH, choose optimized organic fertilizer for each growth stage.

Trimming Scissors

Development can be intense using coco coir. You will experience prolific growth and may need to de-foliate. Have scissors on hand if you need to trim excess leaves and prevent moisture buildup.

Best Strains for Coco Coir Cannabis

Coco can produce healthy plants from any strain (cultivar). If you’re a newbie, choose a cultivar resistant to nutrient fluctuations to avoid burns and deficiencies. Some examples are sturdy indicas like OG Kush (get seeds here) or Grandaddy Purple.

How to Grow With Coco Coir

Before you get growing, the first step is preparing your coir fibers. The rest of the process is fairly straightforward and similar to gardening with soil.

Step 1: Rehydrate the Coco Coir

The first step is turning your dense coco bricks into a loose marijuana medium. Grab a big bucket (this can save a big mess) and let them soak in water for about 10 minutes. Then manually break up the bricks into chunks. Introduce Cal-Mag, perlite, or other amendments as needed.

Step 2: Pack the Pots

Fill fiber pots with the coco coir mixture and leave them in a breezy spot for a day to drain excess water. You can also top-dress your mix with volcanic rock dust like you would with pots of soil.

Step 3: Introduce the Plants

Once your seeds germinate, and the young plant grows two nodes, transplant them from potting soil to your coco coir mix. Drench the substrate with water and nutrient solution.

Must-Follow Tips for a Successful Coco Coir Grow

Optimize your coco coir growing outcomes with these helpful tips:

  • Start with half-strength nutrients. The feeding schedule begins early in coco, but young crops don’t need as many minerals. Increase feedings gradually over several weeks.
  • Know signs of nutrient trouble. Burns and deficiencies happen more often with coco coir than soil (but less than Rockwool). Early symptoms to watch out for include leaves that are yellow, wilting, or falling off the plant.
  • Transplant regularly. Cannabis plants need plenty of space as their root systems rapidly expand. Transplant at least once in the vegging stage and once before flowering.
  • Water generously. How much you water is different for every grow. Coco coir should be saturated for optimal development, but remember that the risk of over-watering is much higher than other soilless mediums. Monitor moisture levels and adjust accordingly (a dry-back period is crucial for cannabis).

The Bottom Line

Coco coir growing is perfect for cultivators looking to increase harvests without transitioning to a hydroponic setup. Mind the feeding schedule and pH levels to ensure heaps of sticky buds.

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Frequently Asked Questions

Is coco coir better than soil cannabis?

No system for growing marijuana is inherently better than another. Ultimately, bud quality depends on crop care. That said, coco coir usually produces high quantities of potent, flavorful weed. You can also combine coco coir and soil to make your own mix.

Does coco coir yield more?

Cannabis plants grown in coco coir have the potential to produce higher yields. Because coco coir provides excellent aeration, plants’ roots can breathe better, allowing them to grow larger. This vigorous plant growth in coco coir leads to higher yields.

How long does coco coir weed take to grow?

The life cycle of weed is similar in soil and coco coir. If cultivating indoors, take advantage of coco coir’s shorter vegetative stage, and you can collect buds in roughly three months.