As a growing medium, coco brings together the best of the growing worlds. Made from the fibrous husk of the coconut, coco combines the performance of a hydroponic medium with the forgiving properties of soil, making it an excellent choice for both beginners and experts.
With coco’s natural 70-30 moisture-to-aeration level, over-watering plants is difficult, as water will run off but aeration will remain intact once coco reaches its saturation point. Since it is an inert medium containing little if any nutrients, coco can be watered daily with nutrient solution, delivering a fresh supply of fuel to the roots to accelerate plant growth. That can’t be done with soil, which will restrict the amount of oxygen available to the roots and slow a plant’s growth if watered daily.
While a number of manufacturers have developed coco-specific nutrients that are uniquely adapted to meet the nutritional needs of coco-grown plants, coco is also suited for growers using organic nutrients that would muck up most hydro systems. What’s more, coco beats out most other hydroponic mediums in creating the perfect environment for beneficial bacteria to colonize the root zone and help plants absorb nutrients and ward off disease, while better protecting the root zone from heat than most hydroponic mediums.
Versatility is yet another positive aspect of coco, and growers can add amendments to make coco fit a wide variety of growing scenarios, whether it’s an automated drip system indoors or a hand-watered container garden outside.
The performance of plants grown in coco is well-documented. In a two-year trial of growing roses in coco and granulated rockwool in a recirculating system, the coco-grown roses produced nearly 16 percent more marketable flowers with an 18 percent higher fresh weight compared to the rockwool roses, according to the International Symposium on Growing Media and Hydroponics.
So if you want faster, bigger blooms through hydroponics with the relative ease and familiarity of soil, you may want to consider trying coco.
What is Coco
Coco, also known as coco coir or coco peat, is made from the husk of the coconut. For decades, the sturdy fibers of coconut husks have been harvested to make rope, doormats and other durable items. But years ago, the horticultural industry discovered that the dust and fibers left over from that process were an excellent – and sustainable – replacement for peat moss, a non-renewable resource.
But since coconut palms tend to grow in salty environments, mainly near the ocean, the first commercially available coco products had nearly plant-toxic levels of salts that required the coco to be flushed with gallons of water before it was ever used.
Today, makers of coco products, like Canna, Botanicare and others, have enacted intensive rinsing and aging regimens to produce coco with as little residual salt as possible, making it unnecessary for the grower to flush the coco before transplanting.
In the mix
Unlike other hydroponic mediums, coco gives the grower a high degree of control over moisture retention and drainage, in addition to being the perfect environment for beneficial bacteria and fungi – namely bacillus, mycorrhizae and trichoderma. (Learn more about beneficial bacteria here).
Just like with soil, growers can achieve different degrees of drainage and aeration by amending coco. With plain coco, growers can water almost as they would if the plants were being grown in soil – once every one to three days, depending on the size of the plants and the containers they are in – and provide nutrients with every feeding, since coco contains no nutrients.
But if plain coco is mixed with Perlite, coco can easily fit the precision of drip and ebb-and-flow hydroponic systems.
Botanicare’s Ready-Gro coco-perlite mixes offer growers two different drainage levels right out of the bag, in addition to pumice stone, earthworm castings, seaweed meal and natural sources of humates for your plants to draw on. Ready-Gro Aeration Formula contains 60 percent coco fiber and 40 percent perlite, and can be watered four to six times a day, making it perfect for automated indoor hydroponic gardens. Ready-Gro Moisture Formula consists of 75 percent coco fiber and 25 percent perlite, allowing it to hold more moisture so larger plants – even those grown outdoors – can be watered just once or twice a day. A 1.5-cubic foot bag of ReadyGro coco mix will fill roughly three 3-gallon growing containers.
For plug-and-play ease, Botanicare’s CocoGro is also available in 6”, 8” and 10” BOSS blocks that eliminate the need for growing containers and can easily be used in recirculating drip or ebb-and-flow systems. Just hydrate the coco block inside the bag, poke drainage holes in the bottom of the bag and transplant.
Many growers prefer to create their own coco blends as a money-saving alternative to out-of-the-bag mixes, or to exclude certain organic elements that can muck up recirculating hydroponic systems. Others do so simply to augment coco’s naturally occurring 70-to-30 moisture-to-air ratio to match their cultivation style.
Canna Coco or Botanicare’s CocoGro (available in bags, bricks and bales) can be mixed with Perlite to increase aeration and drainage in the root zone. Growers should avoid using coco-specific nutrients when amending coco with Perlite to keep plants from yellowing and under-performing.
Additionally, a 50/50 blend of coco fiber and Vermiculite is excellent for rooting cuttings and helping seedlings get off to a promising start, as Vermiculite clings to moisture, nutrients and a little air at levels that can be beneficial to young plants.
Since coco is an ideal environment for beneficial bacteria, coco growers often inoculate their medium before transplanting. In fact, Canna Coco comes pre-charged with Canna’s proprietary strain of trichoderma, and Botanicare is now including packages of Zho Root Inoculant, which also contains trichoderma, with 1.5-cubic foot bags of ReadyGro coco mix.
But diversity is important when using beneficial bacteria, since the root zone requires many different species of fungi and bacteria working together to meet all of a plant’s needs. Great White Mycorrhizae is a blend of 36 species of trichoderma, mycorrhizae and beneficials that helps ensure your plants make the most of the nutrients you feed them. Sprinkle half a teaspoon of Great White into your coco when transplanting, and reapply every two weeks at half a scoop per gallon of water. Stop applying Great White four weeks before harvest.
If you are a grower lucky enough to live near a BetterGrow Hydro retail location, BGH’s Actively Aerated Compost Tea will also work wonders for your coco-grown plants. BGH’s fresh-brewed compost tea contains living microbes that help guarantee maximum microbial activity in the root zone far better than off-the-shelf preparations.
If you don’t live near a BetterGrow Hydro location, find a hydro store near you that brews its own compost tea using high-quality ingredients in a top-notch brewer, or make a brewer yourself to produce your own microbial concoctions. Your plants will thank you for it.
Feeding your plants
To match the nutritional needs of plants grown in coco, several manufacturers have introduced coco-specific nutrients that work better with coco’s unique nutrient-binding characteristics.
Among the most popular are the two-part Canna Coco formula and Botanicare’s CNS 17 Coco and Soil grow and bloom formulas. Both are designed to ensure that elements that bind to coco – like potassium, which is critical to how plants use water and other nutrients – are in ample supply and available to plants throughout their life cycle.
“The nutrient you use on coco is going to be extremely important,” said Canna’s David Hill, adding that growers should be cautious when using flowering enhancers loaded with high levels of potassium, which competes with magnesium to bind with coco, upsetting the nutrient balance in the root zone.
Irrigation and flushing
For a mature plant in a drip system, a mix of roughly two parts coco to one part perlite in three-gallon containers will require one to two one-minute irrigation cycles per day to start, achieving about 15 percent runoff each time to flush out salt residues left behind by the nutrient solution. In an ebb-and-flow system, a tray of three-gallon containers containing that same coco-to-perlite ratio could be flooded about once a day. However, BetterGrow Hydro recommends either using a drip system or hand-watering plants growing in coco, since the ebb-and-flow action will create an accumulation of salts toward the top of the coco. (Learn how to build your own drip system and ebb-and-flow system here.)
However, those suggested irrigation cycles are simply rules of thumb and the grower should ensure that the coco goes from wet to barely moist between waterings. Additional cycles may be needed as the plant’s root system grows larger and draws water more rapidly.
Since salts cling to coco, the containers should be flushed with plain water every week or two to remove excess salts from the medium. Another method growers can use to avoid toxic accumulation of salts is to feed-feed-flush, supplying nutrients in two waterings and plain water in the third, to keep the parts per million (PPM) within an acceptable range.
Coco growers feeding with nutrient solution at every watering should periodically test the PPM of the runoff and irrigate with plain water for one or two feedings if the runoff PPM moves beyond 500 PPM.
A week before harvest, it’s good to use a salt-leaching solution – BGH recommends Botanicare’s Clearex – with plain water to fully flush the medium.
For all the benefits of growing in coco, it is not without its quirks. One of the difficulties coco growers encounter is stabilizing the pH of the medium so that nutrients remain available to the plant and beneficial microbes. To prevent nutrient lockout problems, the pH of the nutrient solution should be kept between 5.5 and 6.2.
The pH of the coco medium should be tested as well. Unlike with soil, checking the pH in the root zone by testing runoff is not very telling with coco, because the elements that bind to coco not be at the same concentration in runoff as they are in the root zone.
To test the pH levels your plants’ roots are dealing with, take about a 1-ounce sample of moist – not dripping wet — coco out of a container, stir it with 2.5 ounces of distilled water and measure the pH after the mixture has rested for about 20 minutes.
Many growers love coco. Unfortunately, so does the pesky fungus gnat, a small, winged insect that lays its eggs in the moist upper layers of most growing mediums. While winged adults pose no threat to plants, their larvae do, since they feed off of organic matter – including root hairs and roots, a plant’s life source – and can spread pathogens in the process. Fungus gnats are often very difficult to get rid of once they become established in the grow room, and if winged adults can easily be found on foliage, the wilting that comes with fungus gnat larvae damage is not far behind.
But keeping the fungus gnat curse out of your coco can be as simple as letting the top inch of the medium dry out before re-watering, making it that much harder for fungus gnat larvae – small worm-like creatures that can be seen wriggling through coco – to gain a foothold and grow to maturity in two weeks. However, when it comes to maximizing yields, a teaspoon or two of prevention is always better than a pound of cure.
A teaspoon or two of Gnatrol WDG – a biological larvicide containing the bacteria bacillus thuringiensis, which kills most gnat larvae, but not adults – added to the nutrient solution or to plain water and applied as a root drench can keep fungus gnats at bay, while a dilution of roughly 3 teaspoons per gallon is an effective way to combat a fungus gnat infestation.
Constant monitoring of fungus gnat populations is another helpful method of halting pest problems before they get out of control. To find out what may be lurking in your garden, place Sticky Whitefly Traps near the growing medium to identify whether fungus gnats or other insects are living among your plants.
Growers with severe fungus gnat problems should consider using a PT-1100 Pyrethrum Fogger in conjunction with the prevention and control methods described above.
If you are a soil growers looking for larger harvests or a hydroponic grower looking for a simple alternative, it’s time to get to BetterGrow Hydro or bghydro.com to get your garden coco’d out.