Coconut fibre is now one of the most suitable growing media for cultivating marijuana plants, both indoors and outdoors. This growth medium is used by the most experienced growers, but it is actually very easy to use, as long as you take into account a few rules, which we explain here in this post.
What is coconut fibre?
The fibre is collected from the husks of coconuts, so the substrate is an inert medium. The first step is known as ‘retting’, which is a necessary part of the coconut fibre extraction process. One of the products obtained from retting is ‘coconut powder’. This undergoes various processes including a decomposition step to convert it into a suitable growth medium.
It is important to remember that coconut fibre is an inert substrate, so it does not contain any food for your growing plants, and they must be fertilised each time you water them. This means you have complete control over the nutrients your plants receive.
How do I grow marijuana in coconut fibre?
Coconut fibre provides excellent drainage and helps ensure the roots receive plenty of oxygen.
If you decide to use this growing medium, note that most growers usually obtain better results by adding 30% perlite or clay pellets to the substrate mix.
The quality of the coconut fibre is very important. A clear indication of high-quality coconut fibre are uniform pellets that break up quite easily.
First place the coconut fibre blocks in the amount of water and for the time recommended by the manufactured. Once they are hydrated you will have to break the blocks open, then add the perlite or clay pellets to the growth medium.
We recommend that beginners use coconut fibre to aerate the substrate or treat it with 1 g/L of Calcium (Ca) and Magnesium (Mg).
There is another very popular type of coconut fibre medium used for the rooting step known as Jiffy. Once the seeds or cuttings have rooted, they can be transplanted in any other substrate.
In what formats is coconut fibre available?
- Dehydrated bricks: These are used to aerate the substrate or if the plants are grown directly in the bricks, growers add 1 gram of dolomite lime (solid calcium and magnesium) per litre of substrate.
- Slabs:Son sacos donde podemos cultivar nuestras semillas directamente, ayudándonos de bandejas de cultivo para el drenaje del agua. En este caso, es importante utilizar riego por goteo, o bien un sistema de riego automático.
Ebb and flow or NFT (nutrient film technique) methods can be used with slabs.
- Ebb and flow: This is the typical method where water is fed directly into a gutter or tray.
- NFT (Nutrient Film Technique):This is a recirculating hydroponic system in which the water that drains from the plants is recovered and reused.
During the flowering stage, the plants grow quite big, so we recommend using SCRoG nets.
- Bags: In this format, the coconut fibre substrate is already prepared to start growing your plants.
What materials do I need to grow with coconut fibre?
- A tank of water.
- An irrigation pump.
- An air pump.
- Water heater and cooler.
- Filters, help keep the tank clean.
- An irrigation timer.
Advantages of growing in coconut fibre
- The plant’s life cycle is much quicker. This is because well-oxygenated roots help accelerate every stage of the marijuana plant’s life cycle.
- Thanks to the oxygenation and good water retention, coconut fibre is a great habitat for marijuana roots.
- In addition, it retains phosphorus, which also favours healthy root development.
- It is lighter and easier to handle.
- It retains more air and moisture for the roots.
- It is at a perfect pH for growing.
- It can be reused.
- Alternatively, used coconut fibre can be composted or employed around the garden.
- It is easier to identify when the plants need watering.
- As it is a sterile, clean culture medium, it is less susceptible to attacks from pests and insects.
- It gives growers greater control over their crops. Although the grower initially needs to consider the values and measures to use throughout the cycle, it eventually gives them control over the plants and proves very straightforward in the long term.
Disadvantages of growing in coconut fibre
- The main disadvantage of growing in coconut fibre is that it produces lower quality plants.
- Plants grown in this medium gives have a less intense flavour than those grown in earth.
How should I water and fertilise my plants grown in coconut fibre?
The best thing is to use fertilisers specifically formulated for coconut fibre. Normally, the two most important elements that growers worry most about are calcium and iron; therefore, beginners should use products that correct for any deficiencies inherent to coconut fibre.
Regarding the right time to water, as a rule you just need to lift the pot and check if it feels quite light and the substrate is dry. Ideally you should water gently to avoid water-logging the substrate. The water will make the coconut fibre change to a darker colour. Similarly, it will be light brown when it is dry.
As it is an inert substrate, the plants must be fertilised from the beginning and pH and electrical conductivity (EC) meters used throughout the growing cycle to adjust the values according to the plants’ needs.
We recommend a watering cycle that involves water with fertiliser three times and then once with just plain water (no fertiliser). This will help prevent an excess build-up of salts in the substrate.
Additionally, for the last 2 weeks, you could allow the plants to finish absorbing all the nutrients as this will give them a more natural and individual flavour and aroma specific to each variety.
Some guiding values are given below:
- Week 1 (germination and seedlings): pH 5.6, EC 0.6
- Week 2: pH 5.7, EC 0.8
- Week 3: pH 5.8, EC 1.0
- Week 4: pH 5.9, EC 1.3
- Weeks 1 and 2: pH 6.0, EC 1.4
- Weeks 3 and 4: pH 6.1, EC 1.6
- Weeks 5 and 6: pH 6.2, EC 1.8
- Week 7: pH 6.2, EC 0.8
- Week 8: Flushing the roots pH 6.0, EC 0.0
Growers usually fertilise plants grown in coconut fibre more often than those grown in earth. We recommend using 9 pots with 5 L of coconut fibre in an area measuring 1 m2; similarly, you could plant 16 pots of 5 or 7 L in an area of 1.20 x 1.20 m, etc. You could use the “sea of green” (SoG) growing method or use just a few pots with a SCRoG net.
As we have seen, there is no mystery to growing in coconut fibre – it is both practical and straightforward. You will achieve better and greater root development because it is a sterile, clean growing medium that eliminates many of the pests common to soil-based methods. It includes a small saving in substrate as you can generally use smaller pots, but you will need to use a bit more fertiliser.
Sweet Seeds S.L is not responsible for the misuse of the information contained in this article. Cultivation of cannabis may constitute a criminal offence or administrative misdemeanour; please refer to the legislation on cannabis in your place of residence. Sweet Seeds S.L. does not intend in any case to incite non-legal practices.