How to Plant a Leach Field

Beargrass, a wildflower that can be planted in a Montana leach field.

A septic system has underground pipes that drain into a leach field. In "What to plant over the septic system?" the Washington State University Extension says, "plants do help provide oxygen exchange and contribute to evaporation necessary in the drainfield area. Choose plants with shallow, non-invasive roots. You don't want breakage or damage in pipes from root intrusions." Pipes may be only a foot under ground level, and it is important not to disturb them by digging deeply or rolling wheelbarrows or lawn mowers over them. Watering the plants in the leach field is counterproductive. Plants that do not need supplemental water are the best choices.

Things You'll Need

• Garden gloves
• Rake
• Shovel
• Perennial plants in containers
• Seeds for annual and biennial flowers
• Hose
• Sprinkler

Instructions

1. 

   Choose plants that are right for your climate and will not need additional watering. If you do not know your USDA climate zone, go to the National Gardening Association website and plug in your zip code to find out your zone. Search that website for perennial, biennial and annual plants that you like. If you are interested in native plants, search Wildflower Information.org for additional choices in your zone.

2. Purchase perennial plants in containers from your local garden center. Buy packets of annual and biennial flower seeds.

3. Rake the septic field to loosen the dirt to a depth of 3 inches. Set out the perennial plant containers. Read the plant markers and make sure that the plants are the proper distance apart.

4. Dig a hole for each perennial plant that is two inches deeper than its container. Remove each plant from its container. Gently loosen the roots of the plant. Put 2 inches of dirt in the hole. Place the plant in the hole. Scoop dirt around the plant and pat firmly. The plant should be at ground level.

5. Scatter the flower seeds across the leach field. Rake the field again to be sure the seeds have contact with the soil.

6. Connect the hose to the sprinkler and water the leach field for an hour. Do not water again unless the fall weather is unusually dry in your area.

Tips & Warnings

• Plant the leach field in the fall. Do not plant ivy or other plants that will completely blanket the field. The waste water in the field needs to evaporate.

• Do not plant a vegetable garden in the leach field. There are potential health hazards in the waste water that the field is filtering.

References

• Washington State University Extension
• U of Nevada Cooperative Extension
• Lady Bird Johnson Wildflower Center: Meadow Gardening

Resources

• National Gardening Association
• Wildflower Information.org