Using cardboard as mulch?

Indoor Growing
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I live in a dry environment and my pots of soil are drying out way too fast at the top 1/3 of soil level.

I would like to use mulch, but I am worried about bringing a non sterile thing into my grow that may have eggs from god only knows what bugs in it.

By comparison shredded cardboard sounds like a good and sterile medium to prevent water from evaporating too fast.

I read about it in home and garden magazines, and cardboard is also recommended for compost bins. Everything seems to say cardboard is safe to use, as long as it isn’t wax covered, has no ink, and is just classic brown cardboard.

I know pot growers take things to the next level. Is there anything I should know about before I try using cardboard as mulch?

I think I am going to soak some in distilled water and check the ph if absolutely nothing else.

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2

I’d say go for it, it sounds like it would be a good mulch but be careful because some big distributors, like Amazon, put rat poison on their cardboard to keep rodents and other pests from eating it.

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Here is a much better alternative:

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i would be highly suspect of using the word sterile when it comes to cardboard that’s been traveling god knows where, sat in god knows how many warehouses, trucks, on dirty floors. I’m not trying to insert fear factor, just pragmatic mention that those things might not be as sterile as you hope.

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5

I use it outside as a weed blocker, but would be wary of it inside.

For cheap
You can use a trash bag if you don’t want to buy anything. Could use a Rubbermaid tote top or any type of hard plastic and cut a hole in the center. Just have to have a way to water in, either by removing it every time, or making a slit.

Checkout big hemp farmers, they lay out rolls of plastic sheeting as mulch

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For many years now.

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7

Hydroton (clay pellets) would work also without the cardboard breaking down

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8

Been using it for years too. It’s great for rotating garden beds. I prepare the bed by raking out smooth. Then cardboard, I usually use bigger boxes I have saved. I put a layer of mulch on the cardboard so I don’t have to see it, then I’ll put pots of veggies on top. The ground stays fallow for the season without too much production loss. All the cardboard will be eaten by worms in one season. Keep in mind, no glossy’s, no colored inks beside black. Leaves a layer of worm castings on top. :slight_smile:

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I have cardboard UNDER all my mulch in the garden. It works great in this context at least :slight_smile:

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Seriously? is that on a label somewhere? Lots of people use those boxes as the browns in compost.

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it is most likely sprayed on when the cardboard gets to the warehouse.
cardboard boxes are shipped and stored in flat bundles and they probably only spray the outside of those bundles.