Can't say that I would do it. Nowhere else to put it?

The septic field is built to function, soil and all, as one unit.

Putting plants (especially ones that need irrigation) over some systems can lead to your septic system not filtering out properly and causing problems that didn't exist before the garden.

Some people get away with it and some end up with a costly mess to repair or upgrade their septic system. A lot of it depends on how your system was built and what kind of soil you're working with in your area as far as calculating a real risk. It's supposedly a lot more risky in high-clay areas, but I'm not 100% sure on that one.

Generally not recommended. Food contamination concerns aside, there are no benefits for the garden and some serious potential problems for the field.

Dave

Here is a link that might be useful: Septic tank gardening discussions

Where I live it's actually a LAW that you can't plant anything except grass over your septic fields, and they even come out and check the distance of trees from them as well.
Then again, I live in gestapo-land.

Mmmm...GIANT tomatoes! MONSTER squash! BEHEMOTH lettuce!
Seriously, I'm not sure it would be a good idea. Contamination could potentially become present from contact with soil I suppose. Any root crop...well, forget it.
More likely would be problems with the drain-field. Most modern drain fields are installed very shallow for proper functioning. Just disturbing the soil to a depth necessary for gardening, introducing irrigation as mentioned above, roots, fertilizer applications etc any number of things could upset what is sometimes a delicate balance between septic system happiness and failure.
Though I would be curious what the massive nitrogen load present would do to vegetables...humm.

I've read you have to keep 150 foot distance of a septic tank and I would assume a field as well.

A raised bed with a permanent bottom filled with dirt or compost that would never touch the ground dirt outside of it would be fine anywhere, if that is your only space. A thick tarp on the bottom might be good enough? Maybe pour a concrete floor if you want things to get expensive, but accurate. Ask you local agriculture management office, they would have a definite answer.

You don't want roots to get into the percolation pipes of your septic system. Even annual crop roots will get in there and leave behind solid matter that will eventually clog the pipes, which prevents the septic system from draining and means you'll have to replace it.

for me i see no real issues (by real i mean is there any hard evidence [lots of hype] to show people who have grown above ground vege's over leach fields have gotten sick let alone ended up critically or other illness"related] in hospital?).

lots of leach fields suffer because the ground is poor drainage type, so the grass that grows over the top and grass roots can be invasive except they are perennial most vege's are annual, so once the vege' is pulled whatever roots remain will decompose.

for me it simply doesn't make sense in many applications not to let grass enjoy all that nutrient, and when the grass is mowed do people get ill from handling the clip?? never heard of it.

so my plan would be create a bit of a raised bed between the leach pipe lines, and plant above ground vege's, can't see those roots invading the lines at all and also with mulching of the garden cannot see how any contamination if it exists is going to get near the leaves or fruit of those plants.

we need to work out processes so those who have maybe no other option can enjoy their gardening without the hype. remember on my father's property there was a leach filed for the septic which had soakage problems because it was in clay (installed as per council regulations and inspected and passed) he had a hole dug below the leach field where this excess water gathered he would bucket the water to his vege' patch never did anyone of us get sick.

yes i can see some plants roots especially perennial can be aggressive and clog the pipes if planted on the lines or over the field (some trees will invade the system with their roots from up to 30 meters away), but we are talking above ground vege's here. i also see no root issues growing fruit trees say 3 meters below the leach field to avail of underground seepage from the field, surely all these things that suck up moisture will and can help the field work more efficiently?

refer to the humanure process of providing valuable nutrients. this water has come from a seperation tank, and plant roots just can't suck up any pathogens that may be there for any contamination of the leaves/fruit of the above vege's it would need to watered over them and then the plant material eaten raw and unwashed for their to be any health risk surely?.

pathogens are well dealt with by the soil structure that is the bacteria and worms that are there for the purpose of making nutrients available to plants.

and what do people do with the lawn clip from that field? ok some dump their grass clippings others compost them for their gardens (good one) dumped/trashed clip probably ends up at refuse station and recycled back into their composted material which often has bio humus from sewerage farms added into it and gardners can't get enough of this stuff for their gardens.

every thing we do takes common sense.

len

Here is a link that might be useful: lens garden page

This reminds me of how my mom told me when she was a kid growing up, there was this field she and her little friends knew of that grew GIGANTIC blackberries. Like, blackberries the size of golf balls (ok, well, she was a kid, so memory might be fuzzy). She'd go out there and eat them all the time.

She said years later she found out those blackberries were growing over a septic tank!

She never got sick, but maybe she was just lucky. And those were wild blackberries that got there on their own, not planted, so maybe planting things (and distrubing the soil) over a septic tank is not a good idea.

But I bet you'd get big tomatoes!

Len - please don't assume the objections are all hype just because you haven't personally seen the evidence. AG extension offices as well as many counties and state agencies in the US have very strong information backing most of their rules and regulations. Granted some of them may be purely environmental in nature rather than personal safety oriented, but they don't just make them up out of thin air.

You are right that common sense should prevail but for many common sense says don't plant your food crops on your septic field for many reasons. If no other option/location is available, which is rare since in most states acreage is required to even have a septic tank, then simply construct raised beds in the area and hope your leach field never has to be dug up. :)

Dave

g'day dave,

you appear to be supporting something that has no fundamental support in this theory, again take the hype out of it show us the hard case evidence is all i ask. local authorities like to control and govern that is their job but just because they say you can't do it does no mean there is an inherant provable in real time danger they work on 10001% safe method as common sense can't be taught or measured, you choose to support them that is your right also. i assume nothing! i will say all the time this subject and subject of using urine come (the yuk factor subjects) there has never been any one person can say my friend or neighbour whoever got sick or the hospital wards are overflowing for this particular reason.

i wish i had a leach field so i could then say more, i do use urine i share my vege's with all and sundry, they all eat heartingly none have ever gotten sick. all i can do is equate what my father did with the excess water from his leach field. i'm obviously still here talking with you having spent no time in hospital other than for a heart condition.

take a look around the posts there is even yuk factor hype in the matter of drinking collected rain water from a rainwater tank, no matter what the process there will be the yuk factor hype promotors, who have never tried any of the things.

i think it is about the opponents proved beyond doubt their platform. there will always be variables, that is where common snense comes in.

let's be fair now? in an online debate particularly it never pays to get personnal, keep you response objective never subjective.

i too did a search online and found links that say no and others where people are saying yes and saying how they do it. i mentioned specifics in my first post none have been addressed.

len

Len, since you are not in the US (I think?) you may not remember, but in the past few years we've had numerous recalls of spinach and other greens due to E. coli. It was from sewage contamination. Some people died, other were hospitalized. Septic tank systems only partially treat sewage even under ideal conditions. The risk is probably not excessively high, but it is certainly a known risk and one easily controlled by planting elsewhere.

However, roots destroying leach fields and septic tanks is another issue. If roots disturb a drainfield, it can cause breaks in the distribution of water and cause the tank to back up, which is NOT a pretty picture.

In worse cases, the roots can actually block up the lines -- plants are going to be attracted to the water and send their roots to where the water is. A clogged drainfield is very expensive to replace, especially if you local health department requires that you upgrade your entire system to meet current regulations. A sand mound system can cost $20,000 here.

I am not 100% sure, but I suspect adding raised beds over a significant portion leach field would diminish it's capacity. The grass and weeds over the field help handle the water from the system, through uptake and evaporation.

Personally, I would only consider high (~18") raised beds and shallow rooted vegetables over a small portion of the field. Of course, if you plan to get a load of compost or something you can't drive the truck over the tank or onto the field.

But better yet....select another location. Or container garden. There's no upside, it's all risk.

Here is a link that might be useful: Sewage Pathogens from Septic Systems

I have a lime tree growing closly to a well septic tank and havent had any problems with it,other that the limes look like lemons and the tree bares all year,then again I live in the caribbean,then again some other lime trees over here want nothing on mines,I think that would be a cheap compost idea

yes i was expecting the one about the spinach and other greens leaves, we are kept abreast of the news world wide. but you are confusing the 2 surely the water that was sued to wash those greesn may have been the contamnient? and if the suers would have washed them then maybe nothing would have happened, or it could have been contaminated in the packing shed? i'm not sure if they ever realy found out any one thing to blame so just threw a blanket over it.

we have the same products on our supemarket shelves come from all poins of australia, thee ash never been any health problem from people eating this product i ahve consumed my fair sahre of it, the packet does say wash before eating, but does everyone/anyone??

that is of course and etirely different scenero to someone growing as i ahve suggested i would above ground crops that we all wash in any case and most ge cooked. so best not for us to confuse the boundries let officialdom do that they do it best.

yes there are and will be pathogens in septic water even into teh leach field but microbes and worms take care of them in that environment, the ae different ecoli bacteria all around the place the garden soils you work will have them not all are cause fatalities and some a stomach ache that is not debilatating.

but no one is suggesting you drink the septic water or not wash hands thoroughly after all garden work, and no one is suggesting root crops which if eaten raw could very well pose a health problem, but if washed and cooked then no problem the health authorities say this.

like they say if you tend to personnal hand hygene you will lessens you risk to different viruses passed on from contact of contaminated surfaces generally in public places.

so again i ask you do you have hard case evidence of major group health issues and the health system being swamped maybe, i dunno a pandemic??

i see recall of meat products in the USA is this to be blamed on leach fields or bad processing practises?

len

Honestly, I think it's a crap-shoot (wink, wink) either way. The health risks could be nonexistent or they could be serious. Will you know whether or not somebody is flushing expired prescriptions or are you certain a guest doesn't have a medical condition that could contaminate the soil? Do you clean your oven with Easy-Off and then wash your hands, sending that to your veggies?

I would find somewhere else for my veggies. I do not like to do my work twice and it would break my heart to see my veggie beds moved due to a leach field failure. Not to mention, I am not flush (wink, wink again) with $20K to repair a problem if it goes wrong. If I was, that would be where I plant roses.

Heh. Remind me to ask questions before eating any homegrown produce in Australia.

Len - my personal concern isn't with the yuk factor tho I don't ignore it either. My concern is the root factor.

I live out in the boonies with a septic tank and leach field and a gray water leach field too so have been there, done that, and have the bills for replacing the field to prove it. :)

We once had an 8" deep raised bed of asparagus over the gray water field and ate the asparagus figuring other than the soap phosphates in the gray water it was safe to eat. But then the field started bubbling up to the surface and stinking to high heaven. Had to have it dug up. Not only lost all the crowns of course but you should have seen all the roots and dirt plugging up those pipes and they were another 2 feet below the bed.

So I say no from personal experience, don't plant over a septic leach field.

Dave

Take a look at the website below.

It describes what you should and should not plant on a septic tank soakaway.

Here is a link that might be useful: What to plant on a septic tank or sewage treatment plant soakaway

I had a relative with hepatitis, now passed away, and he used a septic tank. Who has used your septic tank? You know what I mean. No one caught hepatitis from it, but there is no real composting going on to burn or heat the waste enough to kill bacteria and create a good composting bacteria, the waste was just leached as in not as strong.

I wouldn't eat a spinach crop over his septic tank, if you understand that.

Human manure is good for green growing plants only, fruiting ones will die off or not fruit at all, or even fruit, but not allow the fruit on the vines to mature. You will stare at green tomatoes until the cows come home.

A funny story though, in the defense of the blackberry story, I worked on a weed cutting community work program when I was 15 years old and one of our areas to clean that year was the water department's leech field.

Many of the people were picking green tomato plants growing on top or around the leech fields, can't say they were producing any ripe fruits though. I didn't see any at all and the plants were about 3 feet high.

This made me think a little. And what I came up with is "need more info." I used to edit a research journal for wastewater engineers and read numerous little histories of wastewater treatment. Basically it comes down to this: modern wastewater treament practices are based on the natural model of the earth performing filtration of natural spring water, groundwater, etc. There are lots of trickling bed filters and gravel filter beds and other materials used for filtering...and that's for urban wastewater (there are other processes, some of which are necessary to remove things you hopefully won't find in home wastewater like paint solvent or major amounts of road pollution). The home septic tank is a much smaller, simpler version.

The water you pull up out of the earth, those of you who have wells, has at some previous time been up on the surface mixing with animals and bacteria and all that other lively stuff, then filtered down into the earth. And generally speaking that action renders it fit to drink. It stands to reason that if you have a well and a septic field on your property, some amount of the water that goes out of your septic system ends up in the aquifer that you pull your drinking water out of.

My need to know more info. comes from not knowing how much earth the water moves through before it is rendered drinkable, or if there's a certain depth at which you no longer encounter pathogens. And of course, the type of soil you are draining into must play a huge role in determining such things. But composting temp. plays no role in this sort of natural purification. That's for the solids left behind. :) Now once more, I am not advocating any particular action, but thought that what I know might be owrth adding to the mix. An interesting subject, for sure!

Properly built soil horizons can do amazing things with filtration. Those weird looking spots of "ditches" with plants and weedy looking stuff in parking lot areas or in front of shopping complexes are natural filtering buffers. They are built to exact specifications to get the most effective filtration out of the smallest possible area (land is assumed expensive). Parking lots and buildings shed water. This water can be pretty nasty, as one would expect.

A septic system is following the same process only it's using just the soil horizon creations without adding plants as filtering buffers.

It's generally not a good idea...especially in areas where the soil stays shaded/wet-from-rain...to tamper with how these filtration horizons work.

Here's a picture, for reference, of a natural soil horizon. The slow filtration down to the hard pans which channel water to larger bodies (be it a stream/river or underground source) help filter a lot of stuff. Just imagine this underground and going for a much longer distance. They get less varied and more compacted as the horizons go down very deep, but that very slow movement is part of what helps the filtration and death of some pathogens.

http://farm4.static.flickr.com/3422/3384244078_7eae6bed1c_o.jpg

This is in Panama, btw.

I am having to change my plans for this very reason... but I plan on growing some crops vertically and on raised bed tables⦠about 3ft above the ground⦠I have a nice size sun porch that will become a garden of sorts alsoâ¦I may not be able to grow the deeply rooted stock⦠but I'll grow what i can⦠my uncle had a garden in this very yard for decades⦠those were the sweetest blackberries, cantaloupe, and watermelon when a was a kid...