Hugelkultur and Septic Tanks

Welcome Sepp Holzer and everyone of Holzer AgroEcology. Thank you in advance for taking my questions.

I live in Massachusetts just outside of Boston. The ground is pretty wet and this area of the united states gets pretty cold (USDA Zone 5) and a lot of precipitation (an average of 3.5-4.3 inches a month) each year.

I am planning on building a few hugelkultur beds over a location in my backyard that has a septic tank and drain field beneath it. I find it strange that you can see the top of the septic tank as I thought typically they are usually hidden a few feet underground. This is not my house, I am renting it and the landlord is extremely open to us "landscaping". This is a new septic tank that was installed just this past fall.

You can see the top of the tank in the picture I attached. Its the two green round circles just before the swing set. Also the ground where the septic tank is a small hill about 5-6 feet higher than the rest of the ground around it.

While I try to limit the toxic stuff(seventh generation dish soap, fragrance, color and bleach free laundry soap) I put down the drain I am a little concerned about the septic draining into the hugelbeds. I am already a bit iffy on how well it works because I can most definitely smell a fetid odor in certain parts where I suspect the drain field is. I am definitely making sure to add the septic tank bacterial pellets to the toilet every month but still...Maybe because its so new and the ground is so frozen? Is that why I smell it?

Either way do you think its is safe to build a Hugelkultur on top of a septic tank and drain field? I plan on making the beds at least 2-3 feet(up to 1 meter) above the ground level. Should I make them higher to ensure the plant roots don't get into the drain field? Or is it ok? I plan on mostly planting perennial herbaceous plants and annual vegetables with a few berry and support bushes but no trees yet. Maybe a dwarf variety if its ok with the landlord.

Thank you,
Elia

As someone who has had to have my septic worked on/dug up. If it is smelly now it may need work. I would not build something on top of septic or leech field areas, mostly because it may have to be bulldozed to fix any part of the line even leech field. I would stick with annuals or easily dug up shrubs in those areas, and build your raised bed/hugelkultur in an area where it can stay!

Roxanne

i agree that stink normally means there is a problem that will have to be fixed

those circles look like the normal lids to me, one may even be your well lid

but unless this was taken during the winter, its likely a problem with existing equipment rather than having too small of a field... ours was too small for the load it was recieving and it made the grass around the leach field thick and green, oftentimes in the middle of winter too

i considered throwing in some hugelkulturs now that its fixed to help soak up any excess moisture, but well see how that all goes when we get there

I do not know septic tanks, but i do know landlords.

Most would appreciate knowing that there might be a problem with the ceptic because it was just worked on and there is likely a guarantee. Even if not covered, better to fix a problem while it is still small.

Hugelkultur on Septic Tanks or Leach fields is NOT a good idea. First off to build a hugelbed machinery needs to have easy access. Also the soil for the area will be dug up and moved, disturbing or damaging your septic. This could cause some even bigger problems.

There are also shampoos, detergents, drain-o or whatever else has been put down the sink for the life of the septic. These are persistent chemicals that should not be present in a hugelbed. You shouldn't grow your food on the worst part of your land. Additionally leach fields are often gravel, your soil will drain and slump away into the gravel. This causes two problems, one the soil from your beds is sinking away with each rain, two your gravel bed intended to spread the leachates from the tanks is also getting clogged.

There is surely a better spot on your property for hugelkultur, it would be better to build one there.

Judith, Johnny, Zach, and Chad - Team Holzer AgroEcology

I was just over in the greenhouse part of the forums and someone there built a greenhouse over their septic tank to help it stay warm. By the looks of it..that spot it is nice and sunny!? They need winter sun too. Just an idea of how you could grow something there in containers. It seems near your house.. so nice for a quick trip out for fresh herbs in winter and starts in spring. Keep access to the lid, they sometimes have to pumped out.

With out looking at it and checking smelling around the area I would not agree that it is bad. My house built six years ago has both tanks the holding and dosing abou six inches below surface and caps just above grade. If I don't seal my dosing tank cap fill good and cover around it I can smell the septic smell. Usually the dosing tank is very close to the leach field this does not mean a leach field problem which could be roots clogging undersized and over saturated both of these you will have moisture in part of the lawn near the leach field. If the dosing tank has a problem (power or other) or the leach field is backed up the tank "water" level will rise and there should be an alarm near the electrical panel that will sound indicating a problem

By the way this is an excellent place to put a green house once you get it sealed as it is generally warmer above the tanks.