Don't hesitate to reuse coconut substrate
Coconut substrates can be used without major problems for two or even three growing cycles. Let's look at how to do it, step by step.
Coconut substrateis very popular among indoor growers because of its specific properties. First of all, it holds much more water than soil without losing aeration. It is also favored for its sterility — it does not favor pathogens and contains no nutrients, so you know exactly what the plants have available.
By reusing the substrate you save money and help the natural environment. You can plant directly into used substrate or mix it with brand new growing media beforehand. You can use coconut substrate until its fibers begin to break down; then it loses most of its water-retention capacity and will no longer support roots as well.
A few tips to begin with
First of all, you need to remove everything left in the coconut from the previous growing cycle. Start by removing plant debris — all leaves, stems and roots. If you want to be really sure nothing remains in the substrate, we recommend using an enzymatic preparation to help break down dead biomass.
After a very successful harvest there should be no fertilizers left in the substrate. To prevent salt buildup, rinse it thoroughly with mineral-free water (other water could make the problem worse), ideally water from a reverse osmosis unit or distilled water. For safety, also check the EC and pH of the substrate.
Even in a closed grow tent there is a risk of diseases or pests. It is wise to disinfect the substrate before a new cycle. We have tested a solution of hydrogen peroxide (2 ml / 1 l water), in which you simply soak the substrate. Afterwards you need to rinse the growing medium again. Pathogens and pest larvae are also reliably killed by high temperatures. In practice this mostly means a boiling-water bath and (if you have a tolerant wife) an oven heated to at least 100 °C.
Revitalized substrate can be used without problems for mature, healthy plants. For cuttings and seedlings place a layer of new coconut around the young roots; you can still use the old substrate around the edges of the container. A proven method is to mix old coconut with new before transplanting.
If the coconut already crumbles in your hand, the fibers are short and it clearly won't retain as much water, you don't have to throw it away immediately. Even at that stage of decomposition it has uses: process it according to our instructions and you can use it to improve soil properties in an outdoor bed.
How to recycle coconut substrate?
- Remove all plant residues; all old roots must be gone
- Rinse the substrate at least three times with water (preferably RO or distilled); we recommend using 2–3 liters of water per 10 liters of substrate
- Sterilize the substrate with hydrogen peroxide (35% solution, 2 ml / 1 l water) or boiling water
- If you used peroxide, rinse the substrate once more
What to watch out for?
- If you had problems with pests or diseases during the last growing cycle, do not reuse the substrate.
- We recommend working in a clean environment. Wash your hands or use clean gloves.
- Sterilization removes absolutely everything — including beneficial microorganisms. Do not skip this step because of that; instead add trichoderma and other friendly microbes to the substrate afterwards.
- Peroxide is corrosive; handle it carefully and only in well-ventilated rooms.
- Heat sterilization can produce an unpleasant odor.
- Sterilizing substrate in the oven without discussing it with your wife may cause a divorce.
- If you want to mix old substrate with new, we recommend doing so before it completely dries out.
If you have any questions after reading the article, do not hesitate to contact us at info@higarden.cz.
We recommend:
- BioNova Cocomix Plus - first-class coconut substrate
- Plangron Purezym - a great source of enzymes
- Plant Success Orca - adds beneficial fungi and bacteria to the substrate
Other articles:
- How to make plant propagation easier?
- How to recognize quality seeds?
- Enzymes and your garden