Growing in coco has become a popular growing medium for a number of reasons:

  • Coco promotes strong root and plant growth
  • Coco is a more sustainable and environmentally friendly alternative to traditional peat
  • Coco lasts 3 times longer than peat
  • Coco is light
  • Coco is odorless and uniform in composition
  • Coco is pH stable in the ideal range – near neutral (6-6.7)
  • Coco contains significant amounts of phosphorous (10-50 ppm) and potassium (150-450 ppm)
  • Coir has a high cation-exchange capacity, meaning it can store unused minerals to be released to the plant as and when it requires it
  • Coco encourages beneficial bacteria and discourages harmful bacteria (inhibits pathogens like pythium and phytophthora)
  • Coco drains well and is difficult to over water
  • Coco holds 22% air even when fully saturated
  • The top layer of coco always remains dry, leaving behind no chances of fungal growth
What is coco?

Coco coir is the outer layer of husk that surrounds the coconut. After coconuts are harvested, the fibrous husk is removed. From this husk, three main horticultural coir products are produced: coir chips, coir fiber or coir pith/dust. Coir dust retains water well (up to 8 times their weight) while the fibers and chips help with air space and drainage.

There are many brands and types of coco coir available. To ensure the health of your crop, we recommend that you use only washed and buffered coir products like Gold Label Coco or Slacker, as coco coir naturally contains a lot of sodium ions that cling to the coco coir like a magnet.

When to use coco

Coco is good for: hand watered plants, drip systems, auto pots, and Dutch buckets.

How to prepare unbuffered coco

The buffering process involves pre-soaking with a buffering solution high in calcium (like Cal-Mag Plus and CaMg+), which displaces the sodium and balances the naturally occurring potassium. After the soaking period, the media is washed with water and a flushing/clearing solution (like Flawless Finish or Clearex), which removes the displaced sodium, leaving the calcium in the coir. This buffering process prevents unwanted draw down or ‘lockout’ of calcium and magnesium, and avoids sodium toxicity issues.

To help determine the quality of your new and unfertilized coir fiber, flush 1.5 liters of distilled water through 1 liter of growing media, and measure the runoff with a dissolved solids tester. An overall value of 150 ppm or less characterizes a very pure material, while values up to 500 ppm have likely been treated to condition the media. Values greater than 500 ppm should be suspect in containing excessive sodium levels and should be flushed until a TDS reading of 150 ppm or lower is achieved. Sodium levels should be kept as low as possible.

Planting with coco
  • After the coco has been washed and buffered, to increase aeration, we add an equal amount of perlite for a 50/50 mix.
  • Add any Mycorrhizae (Great White, SubCulture M), inoculants, and dry hormones to the mix. Mycorrhizae are a reliable way to give a young plant a helpful boost.
  • For the first feeding, create a diluted (50% strength) nutrient solution, formulated for your plants.
  • To help prevent shock, we suggest you add B vitamins like Superthrive or B-52.
  • Mix the nutrient solution into the dry ingredients until the consistency is like loamy soil.
  • Fill your growing container to the height that will support your plant or seedling. Don’t compact the mix, any more than it takes to keep your plant in place.
  • Carefully place your plant or seedling in the mix and fill around it until the mix just covers the base of your plant.
  • When watering your plants, saturate the coco until there is about a 10% run-off.
  • Allow your plants to go from wet to barely moist before re-watering.
  • If you are using a drip system for watering, you normally will need only two drippers to create full saturation throughout the coco.
  • Because coco holds onto some nutrients (such as calcium, magnesium, manganese and sulfur), it is a good idea to flush the medium on a weekly or bi-weekly schedule.

Want to learn more? Take the 1 hour Coco 101 class or check out the other topics in the GYOstuff Learning Center.
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