You need a container potting mix - a soil-less potting medium. Asking on the Container Gardening forum or just reviewing any number of threads there should bring up recipes for either the 5-1-1 or gritty mix. This forum more properly addresses inground soil issues, not containers.

I doubt an olive tree would fare well indoors - they do not make good house plants.

Thank you toxcrusadr and gardengal48! I currently have an avocado tree growing indoors which is doing well except the soil I used is too dense and as you two both know, it's been less than ideal and I'm worried about hurting the roots from overwatering. I'll check out the 5-1-1 and gritty course mixes.

And I believe the olive tree should do fine indoors. My avocado tree is doing very well even considering my neglect of proper potting mix. I use a nice grow light called the Aspect. Isn't anything overpowering but helps plant and gives off a nice warm white light. Between the light and the proper potting mix I'm hoping it'll really thrive in my library.

Thanks again!

There is a big difference between growing an avocado and an olive indoors!! Avocados are semitropical plants like most houseplants and although they are unlikely to ever produce fruit, they can be maintained indoors indefinitely. Olives are hardy Mediterranean plants and need full sun........preferably at least 8 hours daily, which is virtually impossible in an indoor setting unless in a solarium or sunroom. A grow light will not reproduce that. In areas where they are not hardy in the ground (lower than z7), you can certainly grow them in a container and overwinter indoors (with bright light) but they will be happiest outside in full sun during the warmer months.

I think dwarf olives are common indoor plants. They do need a few hours of sun, and certainly won't fruit at least because they need cold temperatures to flower. They are often used for bonsai. True that a grow light, unless it is a powerful one, and close to the tree, won't substitute for sunlight. Though a grow-light alone might work for a tiny bonasi.

Typically, plants that are native to temperate climates - which would include the Mediterranean area - make very poor permanent houseplants. Sunlight is a big factor in most cases but so also is a lack of winter chill to encourage dormancy/vernalization. This is why potted hydrangeas, mini roses, azaleas, tabletop Christmas trees and other more or less common garden plants fail when they are kept indoors.

Lots of 'hardy' plants are grown as bonsai, but they are grown outdoors during the warmer months and only brought indoors for winter cold protection. I would strongly suggest the same practice be followed with the olive.