Stuck between a walnut and a septic system…

We just bought our first house around this time last year, a real fixer upper. But it was in our budget, in the country, and has 1/2 ac, which, with the price of land around here these days, was as good as we could get.

I’m currently working on designing a forest garden around the house, trying to leave space for some large annual bio intensive beds to build out as our family grows. The east side of the house faces the road and so I’d like some hedgerows and shrubs on that side, and a couple of sun traps leading up to the house with deciduous trees to direct sunlight on and off the house where I want it.

In the back, the land slopes down from the northern corner to the western corner, and even small depressions gather lots of water. That’s also the side with our washing machine, kitchen, bathroom sinks, for possibly a grey water wetland eventually, just down hill across the driveway.

HOWEVER, our septic is at the bottom of the hill. So no woody plants. And a walnut is at the top! But it’s on the neighbors semi-abandoned land. I don’t want gardens too close to the walnut, but everything that can stand its allelopathy is woody. Am I just limited to maybe a wetland and a pond? Or would there be some way to fit, say, a 32x40 8 bed garden back there… how far away from the walnut must it be? If it’s too far away, it’ll be over the septic. I’ve read so much about septic and gardens and don’t want to chance ruining it—at least not yet—it’s already old and I’d rather replace it later than sooner. (And maybe by then the US will understand what vermicomposting septic systems are and I can have one of those permitted!)

Thoughts?

I’m willing to move almost anything over time, so whatever (except the house and garage) is on the little plot I’ve got is insignificant.

The walnut got just barely cropped out of my photo. It’s on the northwest side of the house just across from the brush pile.

Also, I’m in US zone 6b.

Hey R,

Nice post title 😅

I'll preface this by saying--I don't know.

However I just thought of a few ideas that may or may not be helpful for you.

TIL that walnut is allelopathic! Perhaps that area could just be for juglone-compatible plants? Luckily the walnut is on the north side and you're in the northern hemisphere, so shade hopefully won't be a big issue. If it is, you may have the ability to prune the parts that are hanging over your property line.

A few thoughts to consider: you could place a couple of long garden beds on the inside (or outside) of your hedge row on the east side of your property. They may only get half a day of sun, so you may be limited on what you can grow. Also, you could consider curved garden beds around the perimeter of what looks like the grassy areas and sidewalk on the east side of the house.

And finally, the last thought that came to mind would be just to try creating a small, maybe 4ft bed in multiple spots, seeing what areas do best, and expanding outwards after some observation.

Also I agree with not putting anything edible or destructive over the septic!

With respect to what you can grow around the walnut, there are lists of plants that tolerate juglone. It may be easier to find a list of intolerant plants.
With that in mind, if you have time to move things than you have time to find out what will play nice. Remember though that the more mature the tree the higher level of toxicity in the soil. With regards to trying to avoid that as a growing zone, the rule of thumb is the Drip Line. I had many immature walnuts and some young ones as well. Mulberries and most raspberries shrug it off like it's not a thang. The Blackberries and Currants didn't care but I wasn't in rich soils, mostly sand.
If you really want to pick the optimal plants, you need a soil test. OM% is a HUGE factor as to what can be supported. If you have anywhere around that has stands of walnuts, go see what grows there. That's permaculture right out of the books. I know here in WI berry brambles are always around
B. Walnuts, but my uncle said he planted raspberries and as the drip line moved out the berries got killed off. Now he is not a grower/gardener so there may be more at play but observation is always the best route.
The other limiting factor is Sun Light. Finding things that like to grow in the understory would be best. I know that Haskap, N. Highbush Blueberry, and a lot of native raspberry types like the fringes of forests. I know all berry fact sheets say does best in full sun. This is simple not true in all climates.

One idea just popped into my melon. What if you built a trellis or pergola and started your plants outside the dripline and trained them into the area??
I know there are plenty of vining plants that could be used. . .

Hope this gives you somewhere to start!
Good luck
D.

Would raised beds or large containers be an option to consider?  I’ve had friends who did that in soil nothing would grow in, with tremendous success.