We’ve experienced an uptick in Coco coir sales here at Advanced Garden Center and want to take a moment to explain what it is, does and why people are making the switch from traditional soil grow media.
What is coco coir?
Coco coir is the fibrous strands found between the coconut and husk, it’s a by-product of processing coconuts and has recently become available for home gardeners.
Coco looks just like a high grade soil, and comes in bags (ready to use) and very commonly as compressed bricks that expand when water is added (very convenient for shipping).
Many types of coco are available now, coir, bricks, croutons, mats, soiless mixes, etc.
Coco and the Environment
Coco coir is a by-product of the coconut harvest. It can turn into waste or high quality growing medium. It’s a no brainer as to the benefits.
Is Coco Hydro or Soil?
It’s actually “Soiless”, which is like a hybrid of both and needs to be treated like hydro, even though it looks like soil. Use quality hydro or coco specific nutrients and ph to 5.8, and water as if it were soil. You’ll have to feed every water cycle or alternate between the two since coco is an inert medium. Growth for coco is faster than soil, but less than or equal to hydro setups.
Benefits of Using Coco
Hard to overwater – One of the most impressive attributes of coconut coir as a growing medium is the level of aeration and structure supplied to the rootzone. Coco is difficult to over water. Basically, if you supply too much water it will just run out the bottom of the container, and will not become water logged (anaerobic). The coconut fibers are much tougher and coarser than those of peat for example. This means more airspace is available for drainage and to supply the roots and soil life with more air.
Coir fiber will not compact over the course of the grow. You may have experienced filling the pot right to the top with peat at the start of the grow, only to find that a third of the media is “gone” by harvest. What is happening is that the peat fibers are eroding from the force of watering, saline conditions, and the roots compacting the media. This robs the crop of valuable air space in the rootzone, and increases salt build-up as drainage is impeded. With coir fiber there is little if any compaction of the growing media over the cropping cycle due to the higher content of lignins and cellulose found in the physically coarser fibers. In container grown crops, little compaction is evident. Plants receive optimal water to air ratios over the course of the entire crop, not just the first few weeks.
Fewer pests! – You have a lot less chance of spider mites with coco, including most other soil pests. You’re not immune, just safer is all.
Impressive Growth – The most common comment I hear from coco growers is the fantastic growth rate. There are several reasons for this, and the accumulative effect is vigorous plants and large fruits and vegetables.
How to Grow With Coco
The cool thing about coco is it can work with a variety of grow styles with impressive results. For this guide we will focus on good ol’ hand watering, just like you would using soil. A good mix is equal parts coco & perlite, we’ve had the best growth rates with this ratio. The down fall is that it will require more frequent watering since it’s such an airy mix. We normally use roughly 75% coco & 25% perlite for mixes, it’s a great ratio and performs very well. Coco performs well by itself and is very forgiving about watering.
There are a lot of coco specific nutrients out there and we highly recommend them for ease, but beware as some can be a bit pricey. However you can use any hydroponic nutrients. If you are not using coco specific nutrients then YOU WILL NEED to use CalMag or some equivalent supplement to correct the calcium issue that coco has, especially if you are using purified or distilled water. Just follow the directions on the bottle and add every time you use nutrients.
There seems to be a bit of confusion when it comes to watering coco, even intimidating depending on who you listen to. We are here to tell you it’s very simple. First off, use light pots, don’t get some heavy material container, plain plastic works great, buckets or bags work well, smart pots are fine too. If you lift the pot you can tell if it needs watering by how light it is. Learn to judge the halfway weight by feel, when the pot feels less than half full, water it. Try this lift technique for two weeks checking daily. You’ll be a pro at the end of that two weeks.
Indoors, normally plants can go 1-3 days between waterings in 1 to 5 gallon containers. Young plants may go 5 to 7 days between waterings. 10 to 15 gallon containers may go 10 to 14 days. Outside grows may require a more frequent schedule, more so than soil and even more so if you mix in perlite. Once flowering begins, the water consumption will increase and you may be watering daily when you factor in the size of the plant and container size. This may sound a lot like a soil schedule, and that’s just about right. Trying to schedule waterings of more than one plant can get complicated if you’re using the last day as a calculation. That’s why using the lift method is so handy. After some time you can forecast up to 2 or 3 days of when a plant will need watering next with a simple 2 second lift.
Give enough water to see some runoff or almost see it, especially when nutes are mixed in. Runoff with plain water means you’re washing out nutrients, coco is very easily flushed.
Watering Coco With Nutrients
Just like soil, you feed the medium, and the medium feeds the plant. Coco does not have nutrients like soil, so when your plant enters the veg stage, it’s time to feed.
How often to feed is something you will have to figure out, there’s no one way for anyone to tell you and this is where a little grow experience is very helpful. Factors like lighting, pot size, amendments, can all affect your feed schedule. The best approach we can offer is to use a very basic baseline and adjust as needed, or follow the directions for your nutrients at a lower dosage and increase as you see fit. We have yet to use any bottled nutrients at instructed full strength that didn’t burn.
A generic baseline approach would be the same as hydro. Just like in a DWC setup, start feeding around two weeks after sprout with about 150-300ppm. Do this every-other watering and watch your plant. If she looks hungry, try feeding nutes-nutes-water. If she looks over feed try nutes-water-water. You get the idea. You have to dial it in, and every plant you grow may be different. Increase to 400-600ppm after a few weeks, then eventually up to 800-1000ppm. I rarely go over 900ppm. Coco likes frequent low does feedings, but you can hit them hard when needed. If you over do it a flush should get you back in good shape.
This may sound a bit difficult, but it’s not as bad as it sounds, especially once you get a few weeks under your belt. Coco can absorb and release nutrients very quickly, like a broadband internet connection. This is one reason plants grow so well in coco, the high CEC ratio makes plenty of food available to the plant when it wants it.
PH and Coco
Most coco comes out of the bag at 5.5 – 6.5, this is great! When you water or feed your plants, make sure to ph to 5.8. Coco is very forgiving either way, but growth really slows over 6.5.
There is really no difference in starting a seed in coco versus soil. Basically you pour coco into a container, water it, bury a seed about 1/4 inch, and give it a few days. Do not cover with plastic or mist, just keep it moist enough that the top layer does not dry out until the plant has a set of leaves or two.