I have a speaking engagement tomorrow at something called the Clover Club in Kaufman. I am supposed to answer questions on container gardening. I know I should address potting mix, drainage, fertilizer, appropriate size of container to plant material, maybe how to design a fancy pot.
I like to use an inexpensive potting soil mixed with good compost at a ratio of 2/3 potting mix and 1/3 compost. To this I add a little bone meal and cotton seed meal. If the container is large, I will fill the bottom of it with cedar mulch. This keeps the container a little lighter.
I feel like the most important part of a container is the hole in the bottom of it. However, here in Texas in the summer, containers dry out fast. During the hot months the saucer under the container is important as it will hold some water to help the container stay moist.
I like to fertilize my containers once a week with a diluted liquid fertilizer. I used fish emulsion. It stinks, but it works.
Container size is important for practical as well as aesthetic reasons. If the scale of the pot is off, the arrangement will be off. If a plant, for instance a grass, has a large root system the container needs to be larger. Tall plants need a heavier container or the can be easily blown over.
Finally, the fancy pot. Pick three to five types of plants; one that trials, one that is mounding and full, and one that is tall. For this time of year, I have nasturtium, trailing snap dragons, and a sweet myrtle. The sweet myrtle is in the middle, the snap dragon in a circle around the myrtle, and the nasturtium at the edge to trail over the side of the pot. I would take a picture, but the nasturtium is tiny. It will be prime in about three weeks.
Oh I saw something cute the other day. Someone had taken old paint cans and drilled holes in the bottom for drainage. They potted them up, hung them on a hook by the handle - instant hanging basket.