How Much Potting Soil Do You Put Into a Vegetable Garden?

Potting Soil

• Vegetables grown in containers should not be planted with soil from the outside since outside soil tends to be too sandy to ensure healthy growth. Vegetables respond well to a lightweight potting mix that is porous enough to drain well but is also dense enough to retain enough moisture to meet the plant's needs. Virginia Tech Extension Horticulturalist Diane Relf recommends a mixture of 30-percent perlite or coarse matter. Vegetable gardeners should avoid soilless, mixes as they tend to be too lightweight and too nutrient-deprived for container growing.

How Much to Use

• The amount of potting soil or other growing media to use depends in large part on the vegetables you are growing and on the size of the container, but there are some general rules of thumb to follow. Fill the container up to 1/2 inch from the top with the soil mixture you chose. It is often advisable to dampen the soil mixture first. Sow the seeds into the potting soil and water the plants thoroughly.

Long-Term Care & Potting Soil

• Exercising effective long-term care techniques is just as important to your plant's health as is using the right amount of potting soil. Because container-grown vegetables use a smaller volume of soil than do vegetables grown outside, they can dry out relatively quickly. The amount of moisture the plant drains also depends in large part on the type of potting soil you chose and on the amount of sunlight the container receives. In general, water the plants until you see the water drain out of the holes on the bottom of the container.

Other Considerations

• While soilless mixes are generally not recommended for container vegetable growing, some soilless mixes may be suitable for your vegetable garden. If you choose a sterile prepackaged mix, you can add some garden soil to it prior to planting in order to add weight and density to the mixture. Keep an eye out for any insects or weeds that may have traveled into the containers with the outside soil. For a homemade soilless mix, Relf recommends a mixture of one part peat moss, one part garden loam and one part clean coarse builder's sand, with slow fertilizer and lime added as needed.