Raised beds on drainfield

I did a few quick searches in the various forums and didn't get much back on this.

I live on the base of a mountain. Very tall trees and somewhat sloped land. My only option for a sun garden was on the lower half of my drainfield. The drainfield as a whole is maybe 80 feet by 50 feet, with 7 runs. I know this as my yard is terraced by the lines. My raised beds cover 3 lines. I want to expand my garden and start putting in rows. Which would of course need to be directly on top of the drainfield. I would grow various crops on the rows, such as kale, beans and squash.

I have seen multiple opinions regarding the placement of my raised beds. I can not see why this would be an issue. We are very perticular of what goes down the drains.

One other key part is I have a grind and pump system so the material sits in a tank is put through a grinder and fills to a point before it is pumped out to the lines.

No one at my house takes perscriptions, so uptake of pharmies by my plants is not an issue.

thanks,

Willy
,,,Our vege garden is on our drain field. We live in a similar situation to yours.The only available flat space for our vegetable garden was our drain field.We do alternative gardening here in straw bale which basically is raised beds in a sense.I am not sure if I am understanding this correctly but you want to start to put in rows. If you do these in a raised bed fashion it is not a problem..However if you are talking about breaking out the tiller and doing a conventional garden row, it gets more complicated. It is not just what goes down the drain but the drain field itself is designed in certain ways to handle it. Not sure what type of drain field you have but with ours there is a limit to how much soil can be placed upon it, how much water can be passed through it for drainage with out causing soft spots and over flows , etc..Mine is also in a clay and stone base that does not allow extra water to pass through easily.So the raised beds on it give us more control to not keep it from the saturation point that can become a problem with the septic itself.We also graded a very slight slope into our drain field area to carry extra water off it through our stone fence and down to our grapes and a nettle garden.
I would check with those who install the drain fields in your area who are familiar with the your type of system to find out the specs they had had to install the system to for the sanitation department..They may be able to tell you more about whether you can disturb the layering and topsoil of the drain field..

thanks for the reply. We also have clay and gravel. It would be interesting to find out more about our drain field but the folks that built the houses on my street were new and didn't keep good records. Luckly, our house was last and it is the best of all. Still, we have stupid issues, like our french door was installed backward, but anywho.. We don't seem to have an issue with excess water. We have a very large drain field in comparison, i know that could be due to different soils, depth, etc but it does well and as my wife is a massage therapist, her second job is washing laundry. I think you have talked me out of the normal rows, I will continue the raised bed, or something. Did you mention you are doing strawbale gardening? If so, Ive read a lot about it, i would love to hear first hand.

Here is a picture of what I'm working with. Err.. maybe not, something didn't work with this picture, maybe I can take one more in the morning!

Hey Willy,
Seems like there has to be some odd things left from construction,,LOL we get calls quite often to fix mess ups...Each state and even counties and zoning areas have different septic and drain field specs.The people who install in the areas know most of them by heart and will usually explain if any one asks..You will be much happier continuing with the raised beds.So much less hassle over the drain fields..
Yes we do straw bale have for over 5 years.We love it..We have been teaching it in our area for 4 years..I used to have over an acre garden which was so much work.The straw bale are easy for us to use, take less time out of our lives once they are planted..LOL we are also lazy gardeners even though we have over 10thousand sq feet of various types of gardens in..

Adding an extra foot of dirt on top of your drainfield, may hurt your system.
The plant leaves may also hurt the evaporation rate thus hurting your drainfield.
Insects/slugs rain splashes will put fecal matter on your vegetables, which you will then eat. No one wants to get e.coli etc.
Please dont eat strawberries/lettuce from that garden or give to your friends/family when they come over.

if you must have a veggie garden use vining plants on poles such as malabar spinach, beans melons, squash, pumpkins, air potatoes etc and tall veggies such as corn, okra, sunflower.

I planted a bunch of comfrey on my leach field. I use it, and the canada thistle, as well as the dandelions that grow rampantly as chop and drop mulches. Talk about vigorously growing dynamic accumulators..

S Bengi: just curious as to how fecal matter might splash onto plants if it's in a drainage field 2 feet beneath ground, and overgrown with the thickest growth on the property? What are other peoples' leach fields like? In which instance is uncomposted fecal matter exposed to the atmosphere? I'm clearly not a plumber, I just want to make sure there isn't a risk of cross contamination if the material grown above the leach field is cycled indirectly via the SFW through mulching. Thanks.

If one looks at the definition of fecal matter it refers to solids..If I was to have any type of fecal matter showing from my home to my drainfield then I would be out where it surfaced with a back hoe to find out why I have human poo showing up that should be contained in my septic tank.With some systems like ours they require an alarm system that lets you know your tank is compromised and not moving the Effluent out....Fecal Matter is what settles into the tank.

Do I have fecal matter in my garden on heck yes,, it is called manure from animals(chickens in my case) and here is what one man wrote about it as well.
http://topics.blogs.nytimes.com/2009/05/08/manure-safe-or-not/

It has the same basic concerns as the human fecal matter in the garden..

A properly running septic system has septic tank effluent which is what is discharged into the drain field to filter.Effluent is liquid based and if the system is flowing correctly this goes down through the sands and gravels it should not surface anywhere.Yes if you read on line about septic drain fields and such or talk to anyone in the sanitation department they will mention the potential risk of bacteria that can cause illness on foods grown there.They do not seem to mention that when one puts a big lawn over the drain field that it is has the potential to cause the same problems if your children are out rolling in the grass playing.Which yes they do.
I know what goes down my septic system,LOL I also know people who compost and grow using their own bathroom by products .It still comes down to a personal preference I believe.I am far more concerned about those people who put out money for some of these organic soil and compost mixtures like the one made here in Mt that is made from many peoples poo..
http://www.dailyinterlake.com/news/local_montana/article_0991962e-81c5-53d3-b52f-c6617cf1e1a6.html?mode=jqm

Well said. I was actually getting on right now to make a very similar statement. Its kind of funny, i think you said it better than I would, thanks.

The big thing I was thinking is that fact that I do put poo in my garden on purpose. Hopefully it has been composted long enough for the pathogens to die, but i'm not testing it. I never use to wash my garden veggies until I started using poo. That is a minor set back for better results. I have friends who have had drain fields with actual water pooling. You can smell it before you see it. That stuff does seem toxic. There setup is not functioning properly, that is not my case and I do watch for that for more reasons that just my garden.

I'm going to try and repost that picture now. It has been raining like crazy and the plants are about twice the size now. Thanks for the feedback, all of it.

Has anyone thought of/done elevated raised beds using pallets over the drainfield?

My main concern is allowing the drainfield to breath. Building the raised beds on top of 1-2 pallets seems to resolve this issue.

I also have a pretty steep slope so there will have to be some hefty leveling. But that’s another issue.

Anyway, I’m pretty sure we’re going to try this. Just curious if anyone has done it before or looked into it.

I no longer live at this location and I have since been had active engagement in my new house build which includes a drain field.   I have the following updated inputs..

Not all drain fields are installed the same.  
Not all soils around the drain field are equal.  

I was here and walked the new lines at my current house,   They are DEEP.  Like 5 to 7 feet deep.     They don't have to be this deep (i saw the plan details) ,  I doubt at my last house they were given how other things were done.    

and the soil..  My soil now is quick draining,  sandy loam.    I have dug a surface drainage ditch for rain water that runs along the drain field and at the beginning it can have 6+ or so inches,  20 to 40 feet later and there is no water..  It just goes into the soil only to pop out like a spring downhill.    If it rains (okay pours) hard enough the water makes it down the entire ditch to my garden.     I have been working to keep leaves in the ditch (counterintuitive I know, an overflow would cause zero issues) in hopes that they will break down and line the bottom of the ditch so that water stays in the ditch.  

there is no way my drain field at this location would have an issue.    However, at a different site with some clay,  shallow pipes, etc.   I can see how issues could arise and quickly at that.