What soil combination would be best for indoor plants?

I recently adopted two plants. A fern which seems to be doing quite well in the soil it originally came from and a Pothos that i just picked out today( i think rescued would be an appropriate word). I want to continue giving them the proper nutrients conducive to growth, but know very little on the effects soil has on the plant. I know i want to create my own blend of soil because ive heard many frightening things about prepackaged soils. I need to know if i should be concerned about using pre-made blends and if not which brands would you recommend, but i also would like to know which fundamental components i should have in my soil. I live in denver, its quite dry and quite hot at the moment, but it will begin to cool off drastically after about October. I would like to know which soil blend is appropriate for my climate and plant types. Thanks if will really help if i can get a basic idea on these things because i am an amateur gardener.

What container can I put under a child-sized wheelbarrow to catch water from drainage holes drilled in it?

Yes, I asked this in another category, but crafters are very creative and I thought they might have some good answers too, so bear with me.

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I have made a fairy garden in a kid-sized wheelbarrow, and I need to drill holes in the bottom so that the excess water can drain out. Problem is, the wheelbarrow will then leak water, so I need something underneath it to catch the water. Obviously, it should be waterproof, so no cardboard boxes.

I checked the plants section at a couple of stores, but found nothing there. I’m thinking I may need some bizarre random object and I’m hoping someone has come across one.

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Here are the criteria:

It should be dull/dark to fade into the background, as I don’t want it to be noticeable (like not red or white or sky blue or something). The rest of the wheelbarrow is white and red.

The longest it could be is about halfway between 8 1/2 inches and 8 3/4 inches – so 8.5 inches is fine, but 8.75 inches is too long. For you metric users, that’s between 21.59 cm and 22.225 cm. For you non-measurement types, that’s a tiny bit wider than a piece of notebook paper.

The shortest it should be is approx 6 inches (15.24 cm).

The width should be no more than 5 inches (12.7 cm) but is flexible.

The depth can vary, depending on width and length. I don’t want it any deeper than necessary, but it would have to hold a decent amount of water. I’d say about the amount of a sports water bottle or something a little bigger.

I’m quite willing to cut/adjust things to fit, but I am working with exacto knives (like a flimsy box knife) and scissors here, so nothing that requires a blowtorch or bandsaw, please.

The cheaper, the better. I’m aiming for under USD $5, but $10 is about my limit.

Bonus points if it fits the slanted angle of the bottom of a wheelbarrow and/or has a rim that could sit on a metal wire framework or other similar support. At the least, it should be easy to pull it out while full of water and drain it, without significant effort.

I can built a framework around it, but some shapes would be more difficult than others, and keep in mind that it may get moved around, it being a wheelbarrow, so it should be reasonably secure. For example, a sports bottle, being round and having no rim, wouldn’t work very well. A bread pan, although too big, has a perfect rim.

Thanks in advance! Yahoo-ers have never let me down before! I await your ingenious responses.
That’s a good idea, but I need it to be mobile, so the hose couldn’t be connected to anything permanent. But that does open up possibilities; the holes will be in the lowest part, so maybe I could hose it over to somewhere less conspicuous? And I could use a tile as a support platform for whatever container I use. Good stuff! Keep it coming!