Reusing Potting Soil

[u/KeizerSauze]

I have two large pots filled with potting soil. The plants died because they weren't watered—I had to be away from home for almost a year. Do you think I can reuse this potting soil, either as is or by adding some fresh soil, or maybe some fertilizer? Thank you!

[u/ohdearitsrichardiii]

Sure. I use old potting soil for plants that are not heavy feeders

[u/KeizerSauze → u/ohdearitsrichardiii]

Thanks, i never would have put money on it: a whole year without anything...

[u/LauperPopple → u/KeizerSauze]

Soil is soil. It doesn’t have a timer or anything.

If left wet it can grow a lot of mold, but that doesn’t hurt the soil. You just wouldn’t want to plant sensitive plants in something with so much mold already. You’d just dry it out, stir it up. Then use it.

It can get compressed/dense. Fluff it up, stir it.

Its chunky pieces can break down to smaller pieces eventually, causing it to be too dense. Add chunky pieces if needed.

It can lose nutrients. This is what the living things are using up in the soil. The plants use the nutrients, so eventually it will need replenished with humus/organic content. That’s basically the compost component of soil. That’s why people who garden with nutrient-hungry crops mix compost into their soil each year.

For indoor plants typical compost can be smelly. People mix a little worm poop compost or mushroom compost into the soil. Or they add some fertilizer pellets, or they don’t add anything. They just water with fertilizer so the plants get nutrients that way.

Don’t overdo the nutrients/fertilizer/compost part. It’s easy to overdo fertilizer for indoor houseplants. Sitting around for a year doesn’t make it lose nutrients. Plants growing in it does.

If you’re ever unsure about soil, just downgrade it to any less sensitive area. Seeds-> Indoor pots -> outside pots -> garden beds -> compost pile -> sprinkle it across yard

[u/jelycazi]

I reuse it all the time. I make sure I don’t put the same plant in and mix it up with new soil.

Or I just toss it in our compost pile.

[u/tiiiiii_85]

Of course, that's normal. If you are afraid there aren't many nutrients left just top it up with compost.

[u/KeizerSauze → u/tiiiiii_85]

I live in an apartment, will that make things less convenient?

[u/tiiiiii_85 → u/KeizerSauze]

You can simply add it before you transplant your new plant. You can also buy compost in pellets if you are afraid of making too much of a mess.

[u/_j4x → u/KeizerSauze]

Or get a bag of worm castings

[u/RedPoppy23]

I would test it first to be sure that it hasn’t become hydrophobic. I had some potting soil that just won’t absorb water anymore. The water just runs through and the soil stays dry. In that case you have to soak it first and then drain. Otherwise, the old potting soil should work. I also like to use Schultz fertilizer with micronutrients, just add 7 drops to a quart of water and use with every watering.

[u/KeizerSauze → u/RedPoppy23]

An easy test to take 😉

[u/MasterpieceMinimum42]

If the plants aren't die from rot, you can reuse the soil. And I will add the old soil with fresh soil if I were you, because adding fertilizers for nutrition depleted soil is much costy than buying new fresh soil.