Don't think you can just dig a hole in your yard and use that soil in your plant containers. Bad move: That dirt is too compacted. It doesn't offer enough air, nutrients, or moisture to support a container garden. Instead, buy a bag of potting mix that's lightweight and holds water better.
Don't let plant containers dry out—it stresses the plants. Water in the morning or at night. If a plant is droopy, it's getting too much water. If it's shriveling, it's not getting enough. Feeling the soil is another good way to test whether your beginner container garden needs water. If the top inch or so layer of soil is dry, your container garden needs water.
All plant containers need to have a few holes in the bottom to let extra water drain. Allowing too much water to build up in your plant container risks root rot. If your container garden doesn't have holes and you don't feel comfortable drilling new holes, put your plants for containers in a slightly smaller container with holes. Add rocks or bricks to the bottom of the bigger plant container and set the smaller plant container on top.