Is potting soil used outside good for inside now?

Can I use potting soil inside even though I used it to pot something outside before? Do I need to treat it some way? I saw a few ants in that soil. Should I spray it with Safer 3-in-1 Garden Spray that treats fungus, mites, and insects? Then let it set inside for a few days? Then repot.

Treating it isn't a bad idea. Better safe than sorry. You might quarantine whatever you plant in it for a bit too be sure. I've reused potting soil before. The nutrients in the soil were probably depleted by your outdoor plant so adding some slow release fertilizer might be a good idea as well.

There is no harm from using effectively "recycled" soil.

The only issue is you said there were a few ants in it, I'd just put stuff in the soil so that the ants are removed and then use it; although as icanfindroom said quarantine whatever you have for a time just to 'make' sure that all the ants are gone.

icanfindroom makes the best point- the nutrients have been partly depleted. Better to add the used planting mix to a bed outdoors and use new potting mix for your plant to go indoors.

Thanks everyone. You have been very helpful.

Your decision to use or not use the soil shouldn't be based on whether the soil has previously held plants, but on the quality of that soil and it's structural integrity. You cannot make the leap to say there is no harm in using 'recycled' soil - especially if that soil is poor to begin with. Soils, especially peat-based soils, don't collapse at a steady rate, their collapse accelerates exponentially as they age. Any peat soil that has had a plant in it for a year or more, will be in an advanced state of collapse. IF you reuse it, which I wouldn't suggest, you would be best served to mix it with something like 5 parts of pine bark fines and 1 part of perlite for every 1 part of old soil.

Part of this might be OT because it's a copy/paste job from another thread:

In my estimation, the only case to be made for reusing container soils is one of economics, and you'll never find me argue against making that decision. If you can't afford fresh soil, you can't afford it. That said and setting economics aside, you might decide to reuse soil for reasons other than economical. Perhaps the effort involved with acquiring (or making your own) soil is something you might not wish to go through or be bothered with.

In any case, it would be difficult to show that soils in a more advanced state of structural collapse can somehow be preferred to a soil that can be counted on to maintain its structure for the entire growth cycle. So, if the economic aspect is set aside, at some point you must decide that "my used soil is good enough" and that you're willing to accept whatever the results of that decision are.

All soils are not created equal. The soils I grow in are usually pine bark based & collapse structurally at a much slower rate that peat based soils, yet I usually choose to turn them into the garden or give them over to a compost pile where they serve a better purpose than as a container soil after a year of service. Some plantings (like woody materials and some perennials) do pretty well the second year in the same bark-based soil, and with careful watering, I'm usually able to get them through a third year w/o root issues.

Watering habits are an extremely important part of container gardening. Well structured soils that drain well are much more forgiving and certainly favor success on the part of the more inexperienced gardeners. As soils age, water retention increases and growing becomes increasingly difficult. If your (anyone's) excellence in watering skills allows you to grow in an aging medium, or if your decision that "good enough" is good enough for you, then it's (your decision) is good enough for me, too.

The phrases "it works for me" or "I've done it this way for years w/o problems" is often offered up as good reason to continue the status quo, but there's not much substance there.

I'm being called away now, but I'll leave with something I offered in reply on a recent thread:

"... First, plants really aren't particular about what soil is made of. As long as you're willing to stand over your plant & water every 10 minutes, you can grow most plants perfectly well in a bucket of marbles. Mix a little of the proper fertilizers in the water & you're good to go. The plant has all it needs - water, nutrients, air in the root zone, and something to hold it in place. So, if we can grow in marbles, how can a soil fail?

Our growing skills fail us more often than our soils fail. We often lack the experience or knowledge to recognize the shortcomings of our soils and to adjust for them. The lower our experience/knowledge levels are, the more nearly perfect should be the soils we grow in, but this is a catch 22 situation because hidden in the inexperience is the inability to even recognize differences between good and bad soil(s).

Container soils fail when their structure fails. When we select soils with components that break down quickly or that are so small they find their way into and clog macro-pores, we begin our growing attempts under a handicap. I see anecdotes about reusing soils, even recommendations to do it all over these forums. I don't argue with the practice, but I (very) rarely do it, even when growing flowery annuals, meant only for a single season.

Soils don't break down at an even rate. If you assign a soil a life of two years and imagine that the soil goes from perfect to unusable in that time, it's likely it would be fine for the first year, lose about 25% of its suitability in the first half of the second year, and lose the other 75% in the last half of the second year. This is an approximation & is only meant to illustrate the exponential rate at which soils collapse. Soils that are suitable for only a growing season show a similar rate of decline, but at an accelerated rate. When a used soil is mixed with fresh soil after a growing season, the old soil particles are in or about to begin a period of accelerated decay. I choose to turn them into the garden or they find their way to a compost pile.

Unless the reasons are economical, I find it difficult to imagine why anyone would add garden soils to container soils. It destroys aeration and usually causes soils to retain too much water for too long. Sand (unless approaching the size of BB's), has the same effect. I don't use compost in soils because of the negative effect on aeration/drainage. The small amount of micro-nutrients provided by compost can be more efficiently added, organically or inorganically, via other vehicles.

To boil this all down, a container soil fails when the inverse relationship between aeration/drainage goes awry. When aeration is reduced, soggy soil is the result, and trouble is in the making."

Al

If you have more interest, you might find this link, because it explores soils in greater depth, to be of additional interest. http://davesgarden.com/community/forums/t/796311/

You have an amazing wealth of information! I certainly will keep your post for reference.

I live in an apartment and have a very small garden, limited storage space, and just a few plants inside. Therefore, I only need small quantities of products. Since I have no need of more potting soil, it would be ideal to use what I had. The potting soil I had was used for a plant outside for no more than 3 weeks. I have now sprayed that soil and put it in an air tight-container.

This soil may not be ideal but I think it will make do for now until I have more space for gardening and storage.

Thanks again! -- Carol

Interesting topic.

I've noticed that the dirt that comes in with the plant can contain creatures that still survive indoors. I've had earthworms live 7 months in a pot. Kinda surprised me when I unpotted them! There are other things I've found too- don't know if they were good creatures or bad....

I thought using bayer systemic insecticide granules would stop all of this but it doesn't seem to- maybe because worms don't eat the plant.