Tips for preparing your garden: Plants over the septic system may be disturbed or destroyed with repair work. Don't put plastic sheets, bark, gravel, or other fill over the drainfield, or reserve area.
Using smaller rocks causes your septic tank to overflow with water, leading to a backup in your house (Ew). But larger pieces of gravel will cause water to flood the soil around your tank and enter your yard (Also ew). For the best results, use rock that's one and a half inches in diameter.
The best plants you can put on top of a septic drain or leach field are shallow-rooted herbaceous plants. These include perennials, bulbs, turf-grass, weeds, groundcovers, and more. A few examples are holly shrubs, boxwood shrubs, azalea shrubs, hollyhocks, wild violets, and spring bulbs.
Using smaller rocks causes your septic tank to overflow with water, leading to a backup in your house (Ew). But larger pieces of gravel will cause water to flood the soil around your tank and enter your yard (Also ew). For the best results, use rock that's one and a half inches in diameter.
Planting over a septic leach field (drain field) is possible if it is done with care. If you have limited space on your property where you can garden, the leach field may be the only spot for landscaping.
Typically, the drainfield consists of three to five trenches that are 18 to 24 inches deep, up to 100 ft long, with a perforated pipe in 12 to 18 inches deep gravel covered by 12 inches of soil.
Turf grasses are the most common plant selected for over a septic system. However, their shallow roots require frequent surface watering, and require repeated lawnmower traffic to keep the lawn trimmed. Choosing a native garden is low maintenance, requires no fertilizer, mowing, or watering.
How Much Weight Can a Leach Field Hold? While you should consider all of the factors above, many professionals believe that the maximum weight for a leach field is around 10,000 pounds.
A more complex French drain implements the use of perforated pipe at the bottom of the trench to help channel the water. A layer of gravel is placed on top of the pipe to keep out any debris.
Plant grass or keep existing native vegetation. These are the best covers for your drainfield. Direct all surface drainage away from the septic system. Use shallow-rooted plants (see plant list above).
In general, the EPA discourages building on septic drainfields, but there are a few things you can do that are generally considered safe. These can include open-air kennels for pets, lightweight swing sets, or small volleyball or badminton nets.
Grass is the ideal cover for drainfields. Grasses can be ornamental, mowed in a traditional lawn, or in an unmowed meadow. Or, you can try groundcovers and fems. The key to planting over the drainfield is to select shallow-rooted, low-maintenance, low-water-use plants.
Trees known for seeking water reservoirs, such as poplar, maple, willow and elm, should be planted at least 50 feet from the mound. Shrubs should not be planted on top of the mound. Avoid irrigation and fertilization on a mound; in fact, never plan to irrigate this area. Use plants that can withstand dry conditions.
Keeping trees at least 50 feet away from septic systems is ideal, but if you plan on growing plants like willows, shoot for 100 feet. Give your leach field a wide berth when planning out your landscape. Grasses, or even wildflowers, over your septic area make a better alternative.
Best Practices for Mowing Near a Septic System
We advise establishing a zone over and extending at least 10 feet around your drain field where you only plant grass and no heavy machinery rolls over it. This area should also be free of any trees or shrubs with extensive root systems.
You might wonder if occasional driving or parking would be okay. Unfortunately, even infrequent use can harm your drainfield. Unlike driveways or streets that are built for vehicles, your drainfield isn't designed to handle any kind of traffic at all. It's always better to play it safe and keep vehicles off.
It's never a good idea to drive equipment over a septic drain field (leach field).
Plants over a septic field can help to prevent erosion and suck up excess moisture from the drain field. 1 The best types of plants are grasses, groundcovers, and some shallow-rooted shrubs and trees.
Generally speaking, septic drain lines are buried between 18 and 36 inches underground, and the pipes are surrounded by gravel and sand to aid in the filtration and water treatment process.
Only add mulch directly above the septic tank
Also, avoid plastic sheets, landscaping fabric, gravel, or other materials. While they're an easy, good-looking fix, they limit soil airflow and water evaporation, disturbing your septic system.
Vegetable gardening over a leach field is a bad idea. Though properly functioning septic systems won't contaminate the soil with harmful pathogens, there is no easy way to guarantee that the crops grown over a leach field will be safe to eat.
Septic drainfield trench depth specification:A typical septic drainfield trench is 18 to 30 inches in depth, with a maximum soil cover over the disposal field of 36"; or per the USDA, 2 feet to 5 feet in depth.
While the terms are often used interchangeably, a leach field typically refers to the specific area where effluent is discharged into the soil, whereas a drain field encompasses the entire system of pipes and distribution components involved in wastewater dispersal and treatment.