Novice gardeners may not realize that when creating a container garden or potting up a new indoor plant, that native outdoor soil is not conducive to a healthy start for plants. Depending upon characteristics of regional soil, the texture could be hard-pack clay or rocky, which inhibits root-growth process. Diseases, pests and bacteria may be inherent in native soil, so to avoid problems it is best to use a potting soil mixture to start new plantings.
Decide which pots you will be using to figure an approximate amount of potting soil you will need to obtain. The size and type of your plants will dictate this choice.
Procure commercially bagged potting soil, or a planter's mix from a reputable local mulch yard as a foundation for your overall planting mix. The potting soil should include vermiculite and perlite. Empty the original bags of potting soil into a large, plastic storage-type container or new, unused garbage bin.
Purchase equal amounts of sphagnum peat moss, shredded bark mulch or humus and sandbox-rated sand. Add these in equal parts to the potting soil mixing/storage bin. Mix well with a garden fork or spade until all the ingredients blend equally with the potting soil.
Make a drainage hole at least the size of a penny in the bottom of any pots that do not have this already. Place a small cutting of tight mesh screen or clay pot shards over the hole so that upon watering, the soil will not seep out of the bottom with water drainage.
Transfer the potting soil mix via garden trowel, your hands or small shovel to individual pots up to within an inch of the rim. Your pots and planting containers are now ready to receive plants into the healthy, friable soil that is conducive to plants absorbing enough oxygen, water, nutrients and minerals.