I would not think roots in the lines would be an issue from the vegetables, it is bacteria that should concern you. Try this article.

Best regards,

Stanley

Here is a link that might be useful: Virginia Tech Article

g'day joe,

many already grow veges over their leech fields, afer all why let the grass enjoy all those nutrients, the general rule is and probably as some may not wash or cook their vege's properly is to not grow root crops, but as for leaf vege's and fruits why not there is no record anywhere of pathogens somehow ending up in the leaf or fruit structure.

you generally create something of a shallow raised bed and then mulch it.

on our page we have a link to growing over a leech field, the roots of vegetables can only help in dissipating the water level in the field.

len

Here is a link that might be useful: len's garden page

73'of my garden borders on a septic line and this is my 7th year gardening here. As Stanley says, growing vegetables over a septic field will not harm the drain field. There could be an issue with bacteria so to be safe, don't plant root crops....or apple trees there;)

I have never heard of fruits or vegetables absorbing bacteria or parasites. The roots of a shrub or tree or tall plants like corn or trellised cucumbers or squashes feeding from effluent would not contaminate the fruit as long as you didn't pick it up from the soil surface.

The main danger is surface contamination, so you wouldn't want to plant root crops or lettuce (etc) that could be contaminated by the soil. Although they could be washed, bacteria buried in cracks or tiny crevices could be a problem.

Sue

HereÂs my story. There is a family down the road who has lived in town at least 60 years. I grew up friends with their children. My parents had no problem with me spending time at their house however I was forbidden from eating anything while visiting. The reason: The family raised most of their food and their vegetable garden was planted over their leech field. My dad, an avid vegetable gardener and a general contractor who installed septic systems for over 50 years was adamant that the risk of contamination was far too high to take the risk. Oddly enough two of the family members died of a very aggressive form of blood infection within a few years of each other. It makes me wonderÂ..

Dang it. It seems to go both ways!

I can tell you that the dirt over my leech field is bone dry in the summer. So dry, compared to the rest of the yard, that you can see where the drain lines run. It's easy because all the grass over the lines dries up and, pretty much, dies. If you measure the width and length, it's exactly what the health department's records show as the length and width of the lines. I think the stones covering the lines justs causes all the water to drain straight through it.

Another odd thing is that when I dig anywhere in my yard, it's hard clay, but where the septic reserve is, it's super sandy loam; once you get past the 2ft or so of clay.

Ok... I think I know what I'm going to do. I'm going to grow corn, okra and such above it. Stuff that isn't close to the ground like beans on a trellis.

If I don't die, I'll let you know how everything went.

I guess it's time for me to get more compost and manure to start amending the soil. I think I'm going to be limited in what I can grow there, depending on how quickly I can get a new bed setup.

Wish me luck! :)

Well, where I live (No CA) when the grass dries up and gets golden, you can see where all the septic systems run because they are all GREEN! Remember Erma Bombeck's book The Grass is Always Greener Over The Septic Tank?
Nancy

Nancy,

That's the way I've always seen it too. Grass stays green on top of the leach field when it's really dry out. But here in my neighborhood, you either can't see the difference, or the leach field area goes dry faster. It's really weird. I'm wondering if this is occurring due to the depth of the drain lines.

It seems most everyone, in my neighborhood, that knows the depth of their field says they are 8-6 ft deep. I know that the ditches they dug for mine were 8 feet deep. They then filled with 3ft of stone, then the lines went in. On top of the lines, 3 more feet of stone then 2ft of clay was put on top.

mine are less than a foot down to the top of the line, 3ft MAX to teh bottom of the trench. we have a high water table and the state won't allow them any deeper in my area.

during summer my field lines dry up first, just like you think, due to the water draining on out the lines and down deep. but during the spring/fall/winter, the areas where my lines go are the first thing to green up and the last thing to brown off. the grass never completely dies during summer, but it is stunted compared to grass just a few feet away.

we have clay soil here too. last year the cracks in it were just as bad over the lines as they were anywhere else in the yard. with 4 acres, i ONLY water the garden so my clay turns to brick about June every year.

hey joe,

grow vege's there, the brassicas stand high enough above the ground so any splash would not affect them and as i suggested you don't till or disturb the soil above the leech lines you add some organic medium and grow in that as well as mulch it. if your lines get that dry i can't ever see any issues. and as yet all the time i have been on the web i have never heard of a documented case of anyone suffering from growing over leech fields always lots of fear hype but never any case evidence.

sounds like your soil drains very well? most people have problems of water dissipating so that is why they plant over their fields.

len

Len,

My soil doesn't drain. What happens is that rain just bounces off the clay and runs down hill. They back yard is sloped, it drops about 5 feet for every 100 feet. They clay is full of rocks too. The rocks are construction debris because my area was once known for granite. Tons of Granite chunks around here from the old quarry.

When they built my house in '04, it was the last one on the street. What the builder did was, when finishing the lots before mine, they collected the rocks and buried them in my back yard. Where my current garden is, I took out 6 yards of stone with a few beer cans and bottle caps mixed in. I hate these lazy builder!!

Over my leach field, they took the clay they dug out for my foundation and laid it on top. I did a few test digs because I noticed on the info the County Health dept had, it said my septic reserve was sandy loam. The test holes show super sandy loam under the clay. If water hits that, it's going to drain straight down....

What I'm planning to doing next week is to amend the 2 feet of clay on top of my leach field with tons of compost and take out any buried stones in the clay. It's easy to tell where stones are buried because only weeds will currently grow on those areas.

Last year, I did this in my current garden area and my soil there is SUPER. My neighbors are all envious of the dirt there, and I'm now going to do it over my leach field.

I didn't buy a tractor, with a loader, this year for nothin! :)

you drive that tractor and loader over the leach field and you will be digging it up. you are not supposed to drive ANYTHING heavier than a lawn mower over teh field.

I wouldn't worry about roots affecting your leach field if you are planting annuals. If it is perennials, then you might have the roots get into the lines, just as tree roots will, and plug it up.

To play it super safe, you could avoid root crops, but the purpose of the leach field is to remove/kill the bacteria and viruses in the sewage before it gets anywhere. If your lines are buried 5-6 feet deep, the microbes should never work upwards that far for a standard septic design--the water should move outwards and downwards, not upwards. It should never get to the surface. If it did, runoff from heavy rains would be putting the bacteria into the waterways and causing the problems a leach field is designed to prevent. Now if you had an evaporative type system, then you would be bringing the water to the surface and may not want an edible garden on top. Plant roots themselves will not transport the nasty microbes to the surface, only the nutrients and water they absorb.

The different results of green/dry people have had really do make sense. In drier climates, grass roots will move downwards to seek water and find it in the leach field. When dry, the grass will stay green over the leach field due to the underground water it is getting. In wetter areas, the grass doesn't have to root as deep to usually have good moisture, but the soil over the leach field usually has very good drainage, so during dry periods, the ground will dry out quickly and the grass turn brown.