I bought a big bag of perlite at the beginning of the season expecting it would be plenty for all of the 5-1-1 I was planning on making for my various containers but I fell a little short and still need to finish filling 3 pots (fabric pots, actually) for my cherry tomatoes.

The fabric pots will be situated on the ground mostly (two of the three are half on a concrete edging) so it's my understanding that they will act more like a raised bed than a container. Considering this is the forum that really seems to know soil mixes, I'm asking here anyway... What would be the best thing to add to these pots to get them full? I'm not going to buy another big bag of perlite to just use a single gallon of it.

As of right now, each container is about 1/4 full of 5-1-1 mix. I have more of all the 5-1-1 ingredients except the perlite. Can I just leave it out? I doubt anything else I have on hand would be a suitable replacement (just topsoil and mushroom compost).

As the tomatoes get taller, I worry about them shading other plants in the adjacent garden bed and might want to move them up onto my porch. I know this will affect drainage too, especially if I have less perlite in the mix, right?