Coco after harvest

First time grower here and I’ve got GSC autos starting their 3rd week from seed. They are doing great. But I’m wondering…what does everyone do with the coco/perlite that is left over after harvest? I’m assuming it can’t be reused because of the nutrient build up but I haven’t found any grow info for what happens after the harvest is complete.

Thanks in advance for any insight, this forum has already been a wealth of knowledge!

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Not a coco grower but I just toss my used soil in my outdoor gardens. You can wash and reuse coco. I believe it can be reused 2-3 times. Not sure if it’s worth the effort or not so wait for a coco grower to respond. If you don’t plan to reuse you could just toss it.

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I grew in coco my first two grows. I’m currently growing hydro. I threw my coco in the garden. I could’ve spent seeeeveral min sorting out the coco from the roots… if I wanted a headache. … lol :crazy_face: I bought case of bricks.
Ditch the coco and go hydro! :sunglasses:

Oof, I hadn’t even thought about the roots!! :exploding_head::exploding_head::exploding_head:. Okay, definitely not worth the trouble. Being my first grow, I already felt overwhelmed by doing coco and nutrients. There are sooooo many variables it seems. Then I’ve got one side of my grow room that is three times bigger than the other side of my grow room and I’m trying to figure out what the deal is…long story short I need a couple lore grows under my belt before I try anything.

These are my a couple of my GSC auto girls at right at three weeks.

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Looking great! Probably about time to start getting run off readings or have you already done that?
What are you feeding with if I may ask and how much?
Do you have a journal on here?

Just an FYI, coco is hydroponics. In botany, any medium other than soil is considered hydroponics.
I’m guessing what you probably meant to say is, “Go DWC, NFT, RDWC” or something like that.


No, I haven’t tested run off. Actually, not even sure how to do that but I’ll look into it. I’ve been feeding GH and Calimagic. I’ve been using this guide I found online with ph balanced water but I only did the week 1 nutrients once (instead of eatery other watering).

I need to start a journal, I’ve been documenting pretty well since this is my first time. You can see in my original picture the difference in size between the two sets of plants on the different side of the room. The ONLY thing I can think of is that the bigger ones are near a crawl space and I’m thinking my exhaust is pulling cool air from it while the others are a little warmer. Crawl space air is about 70 degrees while the room is generally about 78.


Basically - you water to about 10% runoff. This means raising your pots off the ground and putting a tray underneath them. When you water your plants, let some collect in the trays below. Then, you can check the pH and PPM of the runoff water.
Your local hydroponics store should have plant trays and risers. If you don’t have a local store, growershouse has good prices on them. On a budget, you can get plant trays but use PVC pipe end caps (4 under each pot) for your risers.

When you water your plants, just let enough extra collect in the trays until it gets deep enough to put your meter in to take a reading.

I snapped a couple of photos for you…

Tray with riser:

Tray with PVC pipe caps:

Testing the runoff:

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Not sure if you noticed the post above, but I grew in coco. Pretty well aware of what it actually is. There is nothing like a pure hydro grow… just sayin! :wink:

That’s what I used. As far as runoff goes, like @TommyBahama said you need to capture the water somehow to get the runoff.

Maybe this will give you an idea.

It doesn’t have to be anything fancy. You can get pans at the grocery store. I had block of wood under the back of my trey to make the runoff run toward the front and then use a battery pump to pump the runoff out after I got the readings.

One thing I noticed, even at this early stage, in coco, you can’t over water. The perlite is actually oxygen spaces for the plant. Also as @TommyBahama mentioned there are several ways to collect runoff. You have to figure what works best for you.

There are several ways to feed. Some feed/feed/water and some feed/water I personally have done both. I believe I had more control when I feed/water.
However you choose, I would do it every other day or two. They will tell you if they get thirsty or hungry.

So far they seem pretty happy. It seems I end up watering every other day to two days. Once they hit two weeks old I started Feed/Water. I had the smaller ones on a pallet and could put a pan under them but they were growing smaller so I thought maybe being on the cold concrete the others were directly on could be doing something (my original thought was that air flow under would be good). Sure enough, when I put them on the concrete, they started catching up in size. Everything is such an experiment!!

What am I even looking for when testing? Is there a guide for what’s in range?

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That’s great! your off to a wonderful start.

Try not to get caught up in worrying about how big one is to another. It’s quite common to have same seeds that grow different and even look different. I grew two sour diesels last grow in coco and they were totally different when it came time to flower.

It’s not only an experiment but it’s also addictive.

PH should be maintained right around 5.8.
This is what I used. I got it off the GH website. Hopefully it will help. Keep in mind, it’s easier to add nutrients if they are hungry. If you over feed the nute burn will not get better on the leaves that got nute burn.

When you do a runoff, you are testing the PH and the PPM’s. It’ll become vital that you know what’s going in, and what’s coming out later in the grow. That will tell you how much they are eating / drinking. It can also tell you whether or not you have any kind of nutrient lockout.

Have any question, ask away! That’s why we are all here.

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Not a big forum poster but I started a grow journal and tried to catch up to where I am with the grow (3weeks in)

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I can admit, it’s been a challenge at times trying to keep up with mine. I will say that is necessary for me because it helps me understand what’s going on. I make notes and then re-read later for reminders or whatnot.

If I can help just let me know.

Yeah; it’s soilless. Or media. From the standpoint of cannabis growing it is NOT hydroponics. Anyone who has done both knows the huge difference between these methods. I was chastised years ago by the admin regarding this very subject. Seeing as how he’s a USDA certified grower I’ll take his word for it.


Only here at ILGM - Coco growing is categorized under hydroponics at other forums. And from the rules of botany it definitely is, despite what the admin might claim. I’ll repost the same diatribe I put here almost exactly a year ago on this same subject:

Actually, it is a hydroponic method. Most everyone in this hobby is familiar with active (continuous flow) hydroponics, such as deep water culture, ebb & flow, drip systems, etc. But there are also 2 types of passive (static flow) hydroponics - the wicking method and the Kratky method, both of which simply suspend the plant above the nutrients. It’s all soil-less, the difference is that passive hydroponics use no “active” things like motors, pumps or aerators to maintain the plant.


@violagirl0 I apologize for allowing your thread to go down an unintended path. If you have any more questions, please ask away.

I cut my plants down, use a small planting trowel to pull the tap root and trunk out then replant right in that same container

Then I od the plants with cannazym , it will break down any dead root growth into useable nutrients for the plants.

@violagirl0 i apologize I hadn’t seen this sooner…I smoke my own product……