Counting on Coir By Joseph B. Hanson

In a constantly changing world, it's hard for anything to remain static -- even growing media. For many growers, coir has been an attractive component. But how well does it really work?

Growing media can be a mixed bag, so it’s important to keep aneye on your options. You never know when something new might burst on the sceneor when something about your current growing media will change. For example,according to the Canadian Sphagnum Peat Moss Association, some Canadian peatcompanies will be raising their prices 7-15 percent this year, due to thedeclining value of the dollar and the ubiquitous rain season. While thiscertainly does not affect all growers, it does highlight the importance ofknowing about alternative growing media.

One component that may be worth experimenting with is coir.Manufactured from the fibrous husks of coconuts in exotic places such as SriLanka and India, coir has emerged as a relatively new growing medium. But thequestion is, how well does it work? Growers from all over the United Statesshared with GPN the advantages and disadvantages they’ve experienced in usingcoir.

HISTORY

When you see coconuts at your local grocery store, you areactually seeing them naked. Immediately after they are plucked from trees, thecoconuts’ extremely fibrous husks are stripped and jettisoned into piles ofcomposting waste. After being soaked in water for at least six weeks, the toughfiber, known as coir, is extracted mechanically and spun into yarn. These thinfibers are immensely tough and can be coiled, stretched and compressed withoutlosing any of their strength. For many years, coir was primarily used forropes, mats and other forms of carpeting.

But the environmental benefits of coir have been graduallyilluminated, creating a larger market. Composed of strong cellulose fiber withhigh lignin — which hardens and strengthens cell walls — content, coirdisplays a strong proficiency for holding air and water. The golden,100-percent organic fiber has been found to be an excellent deterrent againsterosion and could facilitate vegetation in slopes by being spread out in vastnets.

Coir’s benefits were quickly realized in growing media aswell. Initially beginning in the Far East, the trend of using coir in mediaquickly made its way through The Netherlands and Canada before finally becominga staple of hydroponic rose growers in the United States. Ron Ferguson, ahorticultural consultant and representative for Millenniumsoils Coir, St.Catharines, ON, Canada, estimates coir has been used by U.S. growers for six orseven years and is being used more all the time. Today, coir is used not justfor hydroponics, but for annuals, perennials, vegetables and more.

ADVANTAGES

There are several advantages to using coir. First andforemost is its excellent wetability and overall consistency. Whether it is 6percent or 100 percent of a mix, growers seem to experience the samesatisfactory results. John Roue, of Frey Brothers, Inc., Quarryville, Pa., uses6-15 percent coir in his soil mixes and says, “It acts as a naturalwetting agent within the mix. It also gives improved physical properties. . .reduces shrinkage and compaction of the mix and. . . allows [for] better airspace.”

A tangible result of this improved aeration is theencouragement of larger, healthier roots. “It initiates roots faster thananything I’ve ever seen,” says Ferguson. “[With bag roses], in 20percent coir compared to none, plants in coir had roots starting [to grow]. . .with 50 percent coir, we had roots going into and throughout the bag. And with100 percent coir, there was a complete root ball in the same period oftime!” Virtually all growers using coir experience improved root growth.”I don’t know if I can exclusively attribute it to coir, but we have phenomenalresults propagating now, with very few losses,” says Ted Biernacki ofTed’s Greenhouse, Tinley Park, Ill. “The rooting is justunbelievable.”

The cost and handling of coir has also shown improvement.While it has been more expensive in the past, the price is no longer a problem.Cost is often dependent on how the product is shipped: Stringy, rope-like coiris more expensive because it is ready for use immediately, while coircompressed into the form of bricks or a pallet is cheaper because it needs tobe expanded before use. “I get it by the seat container, so it’s a lotcheaper,” says Andy Pierce, Montgomery Roses, Hadley, Mass. “It’scompressed more than peat moss. If you buy a brick-sized [portion], it’scompressed like 9:1. . . so when you add water, it expands.”

The resiliency of coir is also very impressive but differsdepending on age and form. “I’ve seen coconut with four years or more onit. . . and watering each day with liquid fertilizer,” says Ferguson,”that hasn’t dropped an inch in the bucket. . . There’s a secret to that,though, in that it’s pre-composted.” Newer coconut husks, however, haven’thad the opportunity to linger for years, so its lifespan is shorter — usuallyup to two years. Coir that has a lower amount of fiber, containing more pulp,also has a shorter lifespan. “It all depends on the condition of thematerial and the type of coconut you’re using,” says Bill Young of AspenNurseries Watsonville, Calif. “The finer it is, the faster it decomposes;the coarser it is, the longer it lasts.”

Another important advantage of coir is that it isenvironmentally sound. True or not, many argue that sphagnum peat moss is adepleting resource and have obtained strict regulations on it in order toprotect the bogs it is extracted from. Coir, on the other hand, is essentiallya waste product, accumulating in biodegradable heaps in Sri Lanka and India.For many growers, using a surplus product is an additional plus — yet many ofthem view coir as more of an amendment to peat than a replacement for it.

“It’s like a synergy effect,” says Roue.”Coir actually improves peat by allowing the water to be taken in morereadily, without the aid of a wetting agent.” Roue goes on to say thatpeat improves coir by providing a particle size that is very suitable to containerproduction. Doug Cole, of DS Cole Growers, Loudon, N.H., uses a similar mixturecalled CocoPor from Stender, and he also attests to the synergy. “Now [ourmedia] mixes more consistently,” says Cole. “So when we get our bags,open them up and mix [the media], we don’t find furballs of coir.”

DISADVANTAGES

The most common problem involving coir is that growers ordera batch and discover its EC is through the roof. They then decide to leech itin order to alleviate its high salt content. What they might not realize,though, is that the coir is salty because the supplier washed the coconut huskswith salt water instead of freshwater. This problem could easily be resolved.”Make sure you’re buying from a reputable dealer,” Ferguson warns. “Therecould be some cheap stuff out there that is no good.” Cheaper coirrequires the additional labor of leeching, while more expensive coir is alreadyat an acceptable EC level. Ultimately, it is up the grower to decide which ismore profitable.

Another disadvantage of coir is its clumpy form, which maynot move smoothly through all pieces of automated equipment. Though there areother, more pulpous forms that may be better, growers might still object tosome of the changes that coir necessitates. “Coir has a lot less cationexchange capacity, [and] you’d have to change your fertilizing practices,”says Martin Stockton, First Step Greenhouses, Temecula, Calif. “It’s[also] a lighter brown color, and as a grower, you tend to use color as anindicator of how moist the soil is. . . basically, you’d have to reeducate yourgrowing staff.”

Reeducating your growing staff is a decision based onpersonal preference of the grower. Similarly, there are some indirect effectsof coir, such as minimizing labor cost and preventing the spread of algae andfungus gnats, that fluctuate greatly depending on personal growing habits andenvironment. Growers that do not experience these results may find themselvesat a disadvantage; however, it is only because so much is contingent on circumstance.

Minimizing labor cost is a possible result because coir hasa high wetability and, therefore, could be watered less, saving labor. Yet manygrowers actually water more, albeit in smaller amounts. Roue offers anexplanation: “If you had the capability to measure the actual volume ofwater, then the volume is probably less. The frequency should be a longerinterval between waterings, but then again, there are different types ofgrowers.” The indirect advantage of saving labor is directly related tothe personal watering habits of the grower.

The possible prevention against the spread of pests is alsorelated to habit. “There have been reports saying, ‘Oh, well, fungus gnatswill still go in there.’ Yes, they will,” says Ferguson. “But I havenot seen an outbreak occur as fast with coir.” Cole agrees, “I wouldnever say, with 7 percent coir, we’re in some way deterring fungus gnats. . .[but] I would say it helps dry out the top surface, meaning it’s not asdesirable to a fungus gnat to come lay its eggs.” Since the spread offungus gnats is directly related to the wetness of topsoil, then how well theyare controlled depends on the grower’s watering preferences. Similarly, algaealso thrives when the topsoil is wet and, therefore, may also be prevented insome degree based on watering frequency. However, for both algae and fungusgnats, one of the most important factors is the environment, which can beunpredictable and differ greatly from location to location.

FINAL THOUGHTS

Coir certainly has its advantages — increased wetability,improved root growth, good resilience, environmental friendliness — but thetrend is to mix coir with other components such as peat in order to reap thebenefits of all the elements in the media instead of just one. As for coir’sdisadvantages, some are preventable; talking to your supplier can easily deterimported amounts of coir that are too salty, chunky or fresh. Otherdisadvantages largely depend on how comfortable the individual grower is;minimizing labor cost and the spread of algae depends largely on personalgrowing habits, and spending time reeducating your growing staff may not alwaysbe a workable option.

However, if you decide to try coir, it’s important tounderstand the pros, cons, conceptions and misconceptions. After all, it isonly by doing so that you can really decide whether or not coir is right foryou.



Joseph B. Hanson

Joseph B. Hanson is editorial assistant for GPN. He may be reached by phone at (847) 391-1037 or E-mail at jhanson@uchicago.edu.



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