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How to Germinate Coffee Seeds with World Seed Supply’s Rinsing Cycle

Coffee makes an excellent houseplant that is very easy to care for.  Coffee plants can even be grown indoors in relatively low light conditions. But growing from seed can be challenging for growers.  The following guide is intended to show you one method for growing coffee seeds. This guide can be applied to any coffea species, including arabica, catura, canephora, racemossa and kona.

Coffee seeds present two primary challenges to growers: They take a long time to sprout, and they are prone to rotting. This is exacerbated by the fact that coffee seeds grow inside a fruit. Any remnants of this fruit material, even if you think it has been cleaned off,  is an absolute magnet for bacteria and mold. So the first step is to remove the papery outer layer covering the seed. The innermost seed should be a very light color. Sometimes this layer will already be peeling off a little.  Make your best effort to remove it entirely.

We ran a side-by-side comparison growing coffea arabica seeds with and without the papery outer coating.  The batch with the seed coat had about double the amount of seeds to start with, simply because it was more work to peel them. But this extra step up front appeared to be worthwhile. The coffee seeds that had the seed coats removed not only needed less intervention to combat mold growth, they actually seemed to germinate quicker.  The smaller batch without the seed coats had two sprouts emerge before the other batch had any. Another advantage of the seed coats being removed is that you can see the taproots inside the seed before they actually emerge because of the lighter color. So you have a much better idea of when they are about to pop through.

In the past, we’ve sprouted our coffee seeds in soil. This is certainly the normal way to germinate the seeds. You can pre-soak the seeds for a day, then bury them in soil and come back to check on them after a few weeks. But we’ve applied a soil-less germination method that we like to use for other seeds that have a long germination period and a high propensity for mold growth to coffee seeds.  This is what we like to call The Rinsing Cycle. The ability to treat the mold and check on the seeds without disturbing them is much preferred. The method is actually quite simple.

Once you’ve pulled off the paper coat, soak the seeds in water for 24 hours. After that, drain the water and rinse them through a strainer under a faucet or sink sprayer in order to wash off any dead material or germs. Place the wet seeds in the bottom of a bowl or tupperware and cover the container with a plate in order to keep moisture in and mold spores out. Your ultimate goal from this point on is just to keep the seeds moist until they sprout without mold getting any foothold. We accomplish this by letting them sit a day or two in the covered container after they’ve been soaked and rinsed. Every day or two, cover the seeds with some hydrogen peroxide to kill whatever may have started growing.  If you see them fizzing a lot, then the peroxide is killing off a lot of harmful organisms. If not, then you’ve probably kept your seeds relatively sanitary.  But in any event, once you’ve let them fizz for a while in the h202,  rinse them through the strainer again. Let the water drain. Then place the seeds back in your container and cover it back up with the plate. By repeating this cycle, you should ensure that the seeds never dry out, and they should avoid mold.  You’ll be able to see them sprout, and you can move them to soil when they’re ready.

Once your seeds have sprouted, you want to let the tap roots get to be about 1/4 inch before moving to soil. Keep them in the rinsing cycle until this point. Then simply stick the seeds in the soil with the tap root facing down. The seed should be pushed about halfway into the soil with the other half sticking out.  The taproot will be fully buried at this point. Use a rich fertile soil.  You may add 1/3 concentration of vermiculite to your soil for extra water retention.

It is vital to make sure the coffee seeds stay moist after germination in order for the leaves to emerge. If the seeds dry out, you may end up with a seed on a stem that never opens up.  Even though you have a stem, the leaves can be entombed in the hard seed, never able to break out. You can spray the seeds themselves on a daily basis to make sure they remain moist and soft.  Keeping the air generally humid will help with this. We’ve even experimented with covering each seed with a tiny piece of moist paper towel, and this worked. It may also be beneficial to use a moist layer of whole spaghnum moss above the soil. This is another way to keep moisture in contact with the seeds after they’ve risen up and out of the soil. Any effort you can make to keep them soft will improve your chances of success.

Once you’ve got coffee leaves showing, you’re past the hard part. Coffee seedlings are usually very easy to grow. You can transplant your coffee seedlings to individual cups or cells and keep them under a small light or in a sunny window. Coffee is a forgiving plant. It tolerates most indoor light conditions and does well at room temperature. Coffee prefers moderate water.  But as long as you don’t let the soil get bone dry, it should not die. If you’re aiming to move your coffee plants outside, make sure to wait until they are at least 6-12 inches and you must make sure to harden them off properly.