I bought potting soil well over a year ago, and left it open (inside the plastic bag) in my rooftop. I live in the Caribbean so it would receive strong direct sun every day.

The soil was relatively dry and had clumps. It’s been there so long that weed, growing inside the plant, made a hole in the plastic bag.

Is this soil still usable?

  • If it has weeds growing in it, it's anybody's guess what you might find living in it if you looked with a microscope. Personally I wouldn't use it for anything where the soil quality was critical to success.
    – alephzero
    Commented Jul 14, 2019 at 0:54
  • I toss a gallon or so of water into the old stuff, and wait a day. That usually rehydrates it. Commented Aug 14, 2019 at 16:29

2 Answers 2


It should be okay - if there's a weed growing in it, its obviously not toxic, though it might by now be full of weed seeds, as well as being relatively inert because its been baked by the sun and left open for a long time. I'd probably risk using it, but would add some basic fertilizer to it, something with an NPK of around 7-7-7, because there will be none left in there now. If you want to keep potting soil for a longish time, its always best to leave it somewhere out of the elements, with the top of the bag shut, or anchored shut in some way.


You can probably use it if you mix it with fresh one and use it only ⅓/-½ old. It did clearly deteriorate but unlikely to become really bad.

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