First things first, what is coconut coir (or coco coir)?
Coconut coir is plant fiber made from the coconut husk. And growing microgreens in coconut coir is definitely a viable option as a growing medium.
The coconut, of course, is the world’s largest seed. Inside the tough coconut shell is soft coconut meat that can be turned into coconut milk, coconut cream, and other products. The shell can also be processed into a wide range of industrial products. The husk can, in turn, be recycled to produce coconut coir.
The reason why a lot of gardeners are turning to coconut coir for microgreen cultivation is actually quite simple. Coconut coir is 100% organic. It will degrade naturally.
You don’t have to worry about it filling up landfills and taking forever to break down. In fact, coconut coir can easily be composted if you mix it with the right activator ingredients and composting materials.
It is also sustainable because coconut coir is a byproduct of coconut production. Coconut is grown every year and you don’t have to worry about depleting a finite global resource when you use coconut coir unlike petroleum.
Growing Microgreens in Coconut Coir
The first step in growing microgreens in coconut coir is to make sure that you use a properly processed coconut coir. My favorite brand is here!
In its raw form, coconut coir is made of really long fibers. You can’t use it in this form. It is just too long. You have to get coconut coir that is pre-chopped up and ultimately allowed to break down quite a bit.
Put simply it should have been “fermented”, much like wood chips are left exposed to the elements so microorganisms in the air would work together to break down wood chips into usable finer mulch. The same goes with coconut coir.
While you can get coconut coir that is freshy harvested and cut, it’s a good idea to go with a source that has allowed it to naturally break down into finer form. In this form, coconut coir is easier to work with. It’s softer and it’s more accommodating to your seeds.
It’s also more flexible in these that when your microgreens start developing roots within the coconut coir fiber, it’s not going to be constricted. This ensures that the plant can grow optimally to the desired height so you can have a sizeable harvest.
This is a big deal when growing microgreens because your profitability, as well as the overall flavor and texture profile of the final product depends on the right length of your crop. And if you grow on a medium that leads to uneven heights and stages of growth, the texture might not be all that consistent. The same goes with your crop’s overall profile.
How to Grow Microgreens in Coconut Coir
The first thing you need to do is to gather all the materials you will need. Pick the seed variety of your choice. For a single bed of microgreens, you’ll need two 10×20-inch plastic trays and another of the same size with holes.
Then you’ll need the coconut coir for your growing media, which is easier to work with than soil. Be sure it’s the peat type that you get, and not the chips. They come in bags or brick form.
Lastly, you’ll need pH Down and some nutrient solution (our favorite brand is Fox Farm). The pH down will allow you to adjust water acidity levels higher, which most microgreens love. The nutrient solution is optional. The seeds can germinate without fertilizer, but adding more mineral nutrients tend to increase yields.
Unpack the coconut coir. If it’s a brick, cut a chunk of it you’ll need and put it in a large container. Pour water on this, and it will start to expand. Once it fully expands, break it down into little pieces with your hands. Keep adding water as needed until it has an even consistency.
Now get the tray with holes and fill it with coir. Make sure you spread it as evenly as you can to get a nice flat surface. Put this tray on one of the regular trays, which will serve as a catch basin.
Grab your seeds and sprinkle them over the entire surface, making sure you get as much even coverage as you can. Mist the seeds generously with a spray bottle filled with the pH-balanced water.
These seeds need a warm and dark place to germinate properly. Get your other tray and put it on the bed face up. As the seeds start to grow during this blackout period, they will push against the bottom of the tray, and this will help them break free of their husks.
Be sure to weigh down the top tray with something around 10 lbs and store it on a shelf, ideally somewhere around 70F. Keep in mind that some crops don’t need weighing down during germination, so find out if that applies to your seeds.
You’ll need to mist the seeds lightly and weigh them back down with the top tray twice a day for about 3-7 days depending on the type of plant. During this time, you can lift the middle tray and take a peek to see if any roots have started coming out of the holes.
Once you see the roots forming, you need to mist the bottom tray as well to make sure they don’t dry out and turn brown. You will know when you don’t have to weigh them down anymore when you can’t see the husks at the top. When that happens, cover them with the bottom of the top tray facing up this time.
Microgreens are more convenient to harvest if they’re taller, and they stop gaining height once you take them out of the blackout phase. So once they’ve reached the desired height, you can stop covering them.
From here on out, give them water mixed with both the pH down and nutrient solution, and pour it on the bottom tray. The microgreens will begin growing leaves, and you’ll need to water them morning, noon, and night until they’re ready to harvest. Make sure that they receive a lot of light!
Give it about 7-10 days and you’ll have tasty microgreens to enjoy!