Grow Mediums Coco/AIrpot setup

DCLXVI

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@One Puff - If you're thinking about giving coco a try:

This is just a quick look at how I like to setup my airpots and coco coir. Since the airpot bases are full of holes the coco tends to drop through when you are loading the pot. I simply put a single layer of unbleached coffee filters down first and it prevents a lot of the mess.

I just bought whichever shape/size were the cheapest. These were on sale 200 for $1. The cone filters work better instead of the basket shape round filters. Just split them down the seam and they fit perfectly along the curved edge. With the round basket filters I fold and tear a couple in half. Slip the edge of the filter under the bottom edge. Doesn't have to be perfect, just tuck it in. They will move and aggravate you, take your time. Once you start adding coco they will stay in place. Add one to the center gap as well.

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Just try and tuck the edge under that bottom row of bumps.

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Add one to the center


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Fold em and tear em!

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Now when you load your coco you shouldn't have a big mess.

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I use a plastic saucer on a wood riser I built with a catch basin for the runoff. Easy to weigh for runoff volume and test for runoff ppm.

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With the 3 gallon airpots a 16" saucer should fit nicely. I drill a single drain hole. These used to be inexpensive saucers. They are only available at HomeDepot and the price is ridiculous now. If you choose to get them they are from Grosfilex and are a quality product compared to a lot of the other saucers out there. If you do drill, the indented band is the place to punch through. These are two layers bonded together. However, if you drill through the center or the dimples, the layers are open and water will get stuck in there. They are strong enough to hold a pot, water, and a huge plant. Very durable.

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I just screwed some short pieces of wood together. A simple plastic bin from Target to catch runoff. The tape bump on the back is to give a little angle to the saucer so the water drains. Just line up the hole with the front. You can rotate the pot but keep the saucer lined up.

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All loaded up. I am currently using Mother Earth Coco. It is already buffered and blended with perlite.

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This is how the whole thing works. I like to pre-soak/rinse my coco before using it. I do test the runoff ppm. Some bags/brands have been very high ppm/ec out of the bag. I just keep flushing seedling strength nutes through until the runoff ppm is close to the input ppm. The seedling 2.5g/gal ends up right around 350-360ppm. After I ran 5L through the pot the runoff was testing in the 370ppm range. Good enough so I stopped there and put the seeds in.

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I am currently using the Jacks 3-2-1 nutrient line. They have a separate clone/seedling mix. I follow their instructions and use 2.5g/gallon with a little silica. My tap water was difficult to use so I have an RO machine. You can also buy gallons of distilled/purified water at the store but it will cost you when your plants get big. Almost all nutrient lines are designed around low ppm/RO water sources. If your tap water has a lot of "stuff" in it, you may find it difficult. Jacks does have a tap/city/hard water blend available. @Cooterjuice is a fantastic grower and he uses the "Jacks for Tap" to great success. You could certainly message him if you decide to try their line.

The big things with coco are:

1) Always fertigate. That is water + nutrients. Never water only.

2) pH is important. Have a good meter. Keep the range to 5.8-6.2 always. It is narrow but works.

3) Runoff. A point of debate but following the old suggestion of 20% runoff works great. By that I mean, if you water in 1000ml you should get 200ml of runoff. Hence, I use the bin to collect and weigh the runoff to ensure correct volume.

4) At some point you will need to water everyday, then twice a day, and even more if needed. You really can't overwater coco unless you try. Water as needed to get the right runoff volume. Just because you put in 1L yesterday doesn't mean it won't need 1.5L today. It moves quick when the plants get big.


I don't chase pH in runoff. I tried it once. If your input pH is correct you won't have issues. I do however test runoff ppm. I think it gives a good idea of how strong your nutrients should be. If I am giving the plant 400ppm of nutrients and the runoff is 250ppm, the plant is using it up. So I will push the ppm strength up. So next few times I water if I give 450ppm and runoff is 450ppm to 600ppm I am giving the plant what it wants. I do try and keep the ppm of the runoff no more than 300 above input.

So, input 400ppm. If runoff is lower, increase strength. If runoff is higher, that is ok but no more than 300ppm over. (input 400, max runoff is 700) Does that make sense? If runoff ppm is too high, lower strength and fertigate more often with more volume. It's ok to get more runoff, just costs you a few more cents.


Let me know if you have questions. I have a new grow thread started and I will try and update with nutrient blend, volume, strength, and runoff numbers.
 
Rather than coffee filters at the bottom, I lay down fine mesh nylon screening cut to size. Inert, cheap, readily available (hardware and sewing/craft supply stores), does the job, recylable, etc. I've also used larger mesh standard nylon window screeening. One could probably also use women's stockings/panties/tights or other stretchy breathable fine mesh fabric at the botton. I avoid metal screening, generally not knowing what metal/alloy is used; don't want metals leaching out.

I've been thinking about using stretchy nylon mesh around the sides of the AirPot. This would prevent coco/media from falling out through the side holes while not affecting air pruning. Has anyone tried this, essentially put nylon stockings around the outsides of AirPots?
 
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