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starting weed seeds in coco

Jiffy pellets are made from coco coir. Jiffys have been popular rooting mediums with growers for decades. Cuttings and seedlings once rooted can be transplanted into virtually any other substrate. Alternatively, you can use 1l starter pots filled with coco coir mixed with 30-50% perlite and transplant to larger containers of your preferred substrate later.

Most coco coir growers like to add approximately 30% perlite to the mix for best results. Although a lot of growers are also mixing clay pebbles in at a similar ratio. With equally great results. So much so, that premixed blends of coco coir and clay pebbles can be found in some online grow stores.


Growing cannabis in soil alone offers good results, but soil amendments such as peat moss and coco coir can make good results great. They add structure, hold water, improve acidity, and boost microbial life.

Peat moss also makes a useful soil amendment. Also known as Sphagnum, peat moss is a genus of around 380 separate species of mosses. Peat moss works to acidify its environment by uptaking cations like magnesium and calcium, and in turn releasing hydrogen ions. By outputting hydrogen, peat moss slowly builds bog-like conditions that can reach deep into the ground. In nature, the mosses eventually form a peat bog.

After several weeks have passed, add the peat moss to equal parts organic potting soil and perlite. Thoroughly mix them in a large bucket. The perlite will help to aerate the mix and keep oxygen flowing through the soil.

Get your containers ready before you start germinating

After you see your first root, it’s time to…

Supplies Needed

If you have a root that is curved or bent, don’t try to straighten it out. Open the Rapid Rooter and lay the germinated seed down gently. It will naturally lay on its flattest side. When you slowly close the Rapid Rooter, the bent parts of the root will end up in the “crack” of the Rapid Rooter that you cut to split it open from the side.

Try to let the seedlings break free if possible. But if you have a seedling that’s stuck in a shell after a day or two, and doesn’t seem to be getting any better, you need to go in and help.

Here are those seedlings about 2 days later. Be extra careful when removing the paper towels. Don’t let the seeds roll around or you won’t know which is which. This is when you’ll be glad you used cheap paper towels, as they are much easier to peel off without disturbing your seedlings.

It took me a couple tries but once I got the technique down, I won’t ever go back to anything else for seed starting. The pH of the water really isn’t important at this stage (in my experience), and the idea that you should never let coco dry out is also something you want to ignore until they are established with a solid root system. the cycle of wet to dry to wet again encourages the root growth. I have never had a seed that did not show a tail within a day or two of soaking that was not viable with this seed starting method. The only seeds I have ever seen not pop with this are the ones that probably weren’t viable to begin with, but your mileage may vary. Here’s the technique I use:

-What you want to do is run enough of the nutrient/water solution through the coco to get a considerable amount of runoff, maybe up to 100-200% runoff, and then squeeze it until it is about as dry as you can get it by hand. Couple different ways to do this: for smaller amounts of coco, an old pillow case works wonderfully as a "strainer" and then you can squeeze it to get the water out. If you’re planting a ton, or transplanting into larger pots (this works brilliantly for that as well, same exact process) and need to do a bigger batch at once, go spend $5-8 at your local Wally World for either a very fine mesh or cloth laundry bag and use it the same way as the pillow case. Either way, you want the coco to be just moist enough to feel it, but not so wet that it leaves water on your fingers.

-For containers, you can go with seedling trays or small plug-sized cups to start out with if you really want, but I recommend you just cut to the chase and start them in the initial container (for me, this would be a 4" pot until the first transplant)

-Plant as per usual, keep the humidity at a nice comfortable level for seedlings/vegging plants/humans (50-70% is fine), and don’t even worry about humidity domes or anything as they aren’t necessary.
-If all went well, you will see seeds breaking surface within 24-36 hours, maybe 2 days at most.

-Soak 24-48 hours (not necessary, but speeds the process along a bit) until you have a 1/4"-1/2" tail