Raised beds on a septic field?

This is a sort of companion question to a thread I started in critter care.  We are in the information gathering phase for a potential small farm project.  Thinking about ways to maximize available land.  There is a septic field and we were wondering would raised beds be an acceptable use of that area to grow edible plants?  If so would we need to grow only edibles without a deep root system?  Would this be organic or safe?

Here I am planning to remove my septic. 

Over a septic field a lot of people will poo-poo the idea, but I like it.  There should be a lot of uses for the area safely both in raised beds & without raised beds.  I also believe some deep rooted plants can help you such as some Comfrey in the area.  The deep roots will go down that far, but it will also convert the stuff it finds down there into green mulch which will help you a lot.

Check out this link, it might help you further.  http://greywateraction.org/

if you go to my blog (below) you'll see (gotta look thru photos) our raised drainfield behind our house that we have gardened now for 8 years..we only really garde on the sides that are sloped down from the top..grass on the very top..but we have forest gardens on all the sides including dwarf fruit trees, shrubs of all kinds, perennials, vines, etc..

Brenda Groth wrote:
if you go to my blog (below) you'll see (gotta look thru photos) our raised drainfield behind our house that we have gardened now for 8 years..we only really garde on the sides that are sloped down from the top..grass on the very top..but we have forest gardens on all the sides including dwarf fruit trees, shrubs of all kinds, perennials, vines, etc..

I checked out your blog, looks like you have an amazing set up.  I read that your fruit trees are still to young to produce.  You mention that it is an edible forest garden, what have you grown that you have eaten?

Depending on the root stock apples can reach down between 12 and 96 inches. Septic fields are not buried that deeply. If I were you I'd only plant on the far end of the field. leave the middle and close edge grass and cut hay or  pasture something on it.

prior to our housefire in 2002 we had edible forest gardens which were producing peaches, pears, apples, grapes as well as raspberry, blackberry and herbaceous crops of all kiinds..

we tried to move the trees when we had the housefire but only one successfully moved, a crabaple..and it still bears..we also have 3 from seed apples that are bearing and one peach that was bearing but it got damaged and had to be removed..our grapes, raspberries and blackberries, strawberries, elderberries and lots of the smaller shrub berries bear every year..but the apple, peach, cherry, pear and other fruit and nut trees that were planted in the last 2 or 3 years are still too young to bear now..possibly we might start getting a small crop from some of them this year..but I don't expect a lot..the oldest babies we have are 3 years old since planting and some were planted as seedlings last year..so they are very small..

I do have 3 full size apple trees that grew from apples..and they bear well, well enough for us to not need to buy apples..but i have 6 baby apple trees of other varieties planted..we lost all of our cherry trees so i put 4 new ones in over the past 2 years..and we lost all of our peach, plum, apricot and pear trees, i do have 2 pear trees that are old enough to bear this year, but the pollinators might not be old enough yet to pollinate them..we'll see, no blooms on them last year.

the nut trees are only 2 and 3 years old..and 2 have had to regrow from damaged tops..so they won't bear for 10 or more years likely.

misfit wrote:
Thinking about ways to maximize available land. 

Just a thought, but if you do tall hugelkultur style raised beds and plant the sides... it could dramatically increase your surface area. For example, if you are going to plant a flat area,  say 8 feet wide x 10 feet long = 80 sq feet. But if you put a tall raised bed in that same area, you could potentially double (I didn't do the math as it depends on the height and the angles) your available surface area, as well as bringing much of the soil to a more convenient height. In addition, if you did it huglekultur style it would help minimize maintenance.

You would need to take care not to crush your drainfield with weight.

One of the concerns of planting on a drainfield is that roots could potentially invade pipes.. depending on how your drainfield is designed, many are a series of pipes with holes in them placed fairly shallowly in the ground. Would you be digging with a shovel or doing things that could cause damage to the drainfield itself?

If you have to water your plantings.... wouldn't that add additional "work" to the drainfield? Could it cause it to back up or work slowly?

I, personally wouldn't want to utilize any edibles that were grown in a flat surfaced area over a drainfield. Would be concerned about bacteria... but I worry about everything.

Good luck!

I'd have no issues eating crops from there (if I knew what had been flushed) but it isn't generally a good idea to mess with the septic area.

A raised bed on top of the septic can easily limit amount of oxygen going down into the system required for aerobic breakdown- as well soil is heavy and will compact the site which is not recommended.

Pretty much any sort of tree may become a problem there.
Heavy livestock (possibly even sheep during mucky/wet seasons) can cause serious compaction.

I would think that poultry (rotated) would work- so long as you don't leave them long enough to completely defoliate the grass. Maybe fenced into to sections, half this week half next week- coop in the middle with doors on either side which you can control which side to let them out on?
It may sound a bit paranoid but septic systems are expensive to replace.

fireweed farm wrote:

I would think that poultry (rotated) would work- so long as you don't leave them long enough to completely defoliate the grass. Maybe fenced into to sections, half this week half next week- coop in the middle with doors on either side which you can control which side to let them out on?
It may sound a bit paranoid but septic systems are expensive to replace.

Rotating chickens is most likely what we would end up doing with this area if we move forward with this plan.  Thanks for the advice.