Question
The grassy strip that has to come out is only PART of the entire lawn, if I cover the grass I want to keep and then spray ROUNDUP on the rest, will I be ok?
Also, yes, we will be using cement block with mortar so what do you mean it will affect the surrounding soil? I don't quite understand; you mean where its accidentally dropped?

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Followup To
Question -
I need to remove a 7 foot wide by 50 feet long strip of sod (mostly weedy). I was contemplating using a sod cutter but never used one. Should the lawn area be soaked the night before? Should it be sprayed with Roundup a week before? We are putting in a 4 foot retainer wall and thereafter we will be amending the soil and planting shrubs in front of it.
Answer -
Hi Chris,

"...using a sod cutter...?"

You should be able to accomplish your goals without using the sod-cutter machine.

 ROUND-UP (or any broad-spectrum herbicide containing 'glyphosate') works efficiently and fast for almost any herbaceous non-woody green plant.  In a matter of days, the area should be dead vegetation which you can rake-up and dispose-of.  Then, after the construction is done, you may want to rent a roto-tiller and work-in  the amendments into the top-soil as planned.

Incidentally, transplanting shrubs in the fall is an ideal time for many selections and most nurserymen will give you a guarantee for survival of so many months.

 Also, if your retaining wall construction  will involve the use of cement and mortar, be aware of the fact that this can alter the soil chemistry in the vicinity of the wall's footing and some plants may not do so well in these areas.  
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Some links:

Only Use plants and grasses rated for your climate-zone.
HORT ZONES from ZIP CODES:
http://www.arborday.org/trees/whatzone.html

To help you decide what plants to use and where to place them check-out the "PLANT SELECTOR" applet:

http://www.growit.com/PlantInfo/
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I Hope this has answered your question(s)!

Visit my Lawn & Gardens webpage for more Lawn and Garden Tips, Facts and Links:
http://hometown.aol.com/eilatlog/lawnol.html

Your Questions and Comments are welcome at ALLEXPERTS.com

___ Jim Gibbs,
    Microbiologist/Botanist
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Answer
Hi Again Chris,

> Round-Up (glyphosate) is a very powerful plant eradicator.  It will kill almost anything that gets a dose, so you will want to be careful in spraying it and do not do so on windy days.  With an average home-sprayer (common 1-2 gallon types), you should be able to control the out-put to apply the chemical directly and only to the vegetation you want to eradicate WITHOUT having to go to a lot of trouble to cover the surroundings.  Just be extra-careful using glyphosate near valuable plants.

>
This notion of cement effects on new landscaping projects near cement works explains some of the losses of plants that builder's and landscapers have to contend with with new houses months after the building is finished.

Chemist speak a lot about something called 'pH'.  This is just a way to measure the acidity of aqueous or hydrated media,... and soils and cement are examples. The pH scale runs from 0-to-14, with pH=7 being exactly 'neutral'. Lab-grade H2O (water) is 'theoretically' 7.  Lemon-juice is around pH 3-4, and caustic Lye can be very high or 'alkaline' (9+).  Fresh cement (in having calcium salts) can greatly increase the pH in soils (to  8.6+), and certain species of plants that need a low pH such as the acid-loving plants azaelas and rhododendrons and many evergreens cannot do well in alkaline (low acid or 'high pH') soils. Cactus likes an alkaline soil.

In cement construction accomplished in the hot days of summers, it is customary and proper (especially with slabs) to water or hose-down the cement periodically so that it will not set or 'cure'  too fast.
This can cause a lot of the area to become soaked with alkaline water and so affect the near-by root-zone ecology.

A dark-loamy humus-rich soil is able to buffer the pH changes, and there may not be any problem IF you have this soil type. A less fertile soil may remain alkaline for a while.


If the construction is well contained and not 'sloppy', the cement and the  mortar washes should not adversely alter the soil's pH.


You can purchase a soil-testing kit at WalMart or at garden centers for around $5 to test the pH.  Most plants need a near-neutral pH between 6.8-7.9 or so. You may be wise to test the soil before and then after any changes are made.

Note that the alkalinity effect of new mortar leaching is temporary and can depend much on the existing soil's physics (i.e., drainage factors), and, again, its 'buffering capacity'.  In time the cement leaching and alkaline effects will dissipate and an older wall will not pose a threat to the root-zone ecology.  So, just work to keep the construction contained and localized, test the soil and establish your plants accordingly.  You can also use additives to adjust the soil's pH, but wait to see what the test-kit measures before doing this 'alkaline alchemy'.

__  Jim G.