Containers are containers :-)) It doesn't make any difference if you are growing plants indoors or out - they still need the same sort of high quality potting medium.

While it's true that the better the quality of medium, the healthier your plants will be, with proper care... it's also true that no two people grow in the exact same environment, so slight to major adjustments may have to be made in moisture retention, depending on variables such as climate, weather, pot location, plant type and size, amount of time you can devote to your plants, etc...

A lot of people use the Gritty Mix recipe for indoor plants, and utilize the 511 recipe for growing containerized plants outdoors. The 511 has a little more moisture retention to it, I do believe, and is suited to outdoor growing. However, one can also use the Gritty Mix for outdoor growing... it depends on individual factors, such as gardening zone, how much time you can devote to plant care, etc... in a very arid, hot climate, the Gritty Mix might dry out too soon to be of great value for outdoor growing, in which case the 511 may be a better choice. In a wetter, cooler climate, the Gritty Mix might be the perfect medium for outdoor growing.

There are variables that must be taken into consideration. One size doesn't fit all. But making adjustments to suit your own individual micro-environment is as easy as adding or changing ingredient portions to suit the moisture retention you're looking for.

Jodik nailed it down! Excellent post. You can also vary mixes 4-1-1 etc if needed too.
I think the key is being able to read your plants, figure out what is happening. it's not easy. Takes some experience.
The more plants you kill the better gardener you'll be! Well you know what I mean. As long as you figure out what happened you can prevent it next time. Independent nurseries often offer diagnostic services. This has helped me understand some problems I was unsure of.

The idea is to avoid killing plants entirely and become a better gardener by first increasing your knowledge, then using your practical experience to validate what you've learned. That's a much faster route to a green thumb than setting out purposely to learn from your mistakes and leaving mayhem in your wake. Trial and error is about the slowest way to learn I can think of when it comes to growing; this, because you have no guarantee that what you see will make sense to you, or that what you THINK you're seeing is what you actually ARE seeing.

Forum pages are full of misinformation that came into being only as a result of someone misinterpreting an observation or a cause/effect relationship and inventing the science to support one or the other.

Plants are plants, there really are no such things as houseplants - only outdoor plants we take indoors because they tolerate indoor conditions better than most other outdoor plants ..... which is why all plants grown under conventional container culture depend on the grower's ability to provide conditions that ensure good root health, without which a healthy plant isn't possible.

Good root health primarily depends on the grower's ability to water properly and maintain an appropriate mixture of air and moisture in the soil at all times, which brings us full circle to soil choice.

Al