[Jason Bennink]

Gray water from laundry is probably best oriented toward an area with various salt tolerant species of trees, shrubs, and groundcover.  There are books on Greywater design by Art Ludwig and Brad Lancaster that show detailed diagrams for building such a system.(pipe dumps into a mulch filled ditch next to woodlands)

If you’re looking to establish something quick and easy.  Sudan grass is crazy strong, but maybe rye would tolerate in winter time, Sun Hemp(crotalari junica) would also be a good summer crop soil builder.  Swiss chard grows huge and is very salt tolerant.  They use that for bio-remediation of saline soils. I once consulted for a guy who couldn’t get anything but swiss chard and beets to grow in his garden.(Beets and Swiss Chard are closely related)  I tested his soil to have 4000ppm TDS which is about 4 times the level most plants will tolerate.

Don’t forget to use a phosphate-free detergent or you are doing the soil surface a dis-service and will eventually see the results in anything you try to grow there.  

If it’s in full sun, I would plant Rainbow swiss chard for shrub like effect with radiant color, various mint species for smell and tolerance, and Dymondia in areas you want to be able to walk over.  

If its not in full sun you might simply dig a ditch and fill it with compost next to the treeline. 

[Jason Bennink]

 Installing a perforated pipe close to street trees can be fitted with a dripper for deeper penetration but also allow for aeration, fertilization, and simplify flood watering with a hose. Generally most important in clay soils.  

In sandy soils subsurface irrigation should be fine.

Also utilizing pavers instead of concrete within range of the prospective treeline, and grading to orient water into planted areas or over permeable hard-scape where water can be focused into useful areas.  I would love to build a system utilizing run-off gutters to supply a “french drain like” subsurface irrigation system to a large scale greenspace or grove.  

In Amsterdam there are trees that are several hundred years old which survive in heavily paved urban areas.  They have injection points(steel fittings coming out of the hard-scape placed strategically) utilized by a truck with a pressurized tank to inject nutrients, oxygen, and water.

[Jason Bennink]

I prefer the subsurface irrigation(Netafim) that Doug referred to.  It’s expensive to install per square foot but you can’t beat the water efficiency. These systems need a pressure regulator(35-50psi) and filter post cylenoid.  Netafim stands out in subsurface irrigation because the emitters are self-flushing and clog resistant.  I like to put between one and three rings around each tree.  One ring per shrub or maybe run a line across them.    I’ve used Netafim alot in somewhat densely planted meandering xeriscapes with weed block. One technique that has worked well for me is to stake down the tubes on the drip emitter every three feet, so that I can track where the drips are being released by feeling through the weedblock.(emitters are 6″-18″ spaced so measure next emitter accordingly)  This way you can prep your area lay down irrigation, lay down weedblock, and plant directly on emitters in an organic yet targeted way.  

Release rates for emitters with Netafim range from .25 – .9 gpm.  Use lower gpm for clay soil, high for sandy soils and middle range for loam to get good moisture distribution.  One feed line generally runs over 100′ linear feet from water source single loaded in the regular size.  They just came out with a smaller diameter tubing that can be integrated with the larger stuff for feeding smaller lines cheaper and less intrusively.

I like the Hunter MP Rotators for water efficiency, although their claims on adjust-ability don’t seem very accurate.(Claims 8′-15′ but reductions in water pressure seem necessary to get below 10′ which subsequently cause the risers to drop- so it doesn’t pan out at any pressure)  These just don’t adjust down as far as they say for tight corners, don’t even try to use these on legs where there is a head with less than a 10′ radius, you cannot integrate with other sprayheads on account of their low gpm distribution being incompatible.  The Hunter PGP series are great for overhead broadcasting large areas on the cheap, but obviously much less efficient than the MP’s.  

[Author]

Posts