Question
We moved into our new home 3 years ago.  We are on a 1/2 acre lot in So. MD that is mostly sloped. Our soil is light brown clay, with lots of rocks and white clumps of clay.  The contractor topsoiled, seeded, and blew straw when the house was built.  Due to the slope, however, the rains that year washed way most of our topsoil and straw, leaving ruts, uneven ground and an absolutely miserable lawn to manage.  Lacking the funds to handle the problem then, we are now focusing on getting the lawn established.  We eventually want to plant zoisia plugs, but need to establish something before we do the zoisia.  My questions are:  1. How can we stabilize 15 truckloads of topsoil and keep it from washing down the hill in the meantime?  Should we till up the existing yard and re-grade? or just lay the new topsoil over the existing weeds? Do we need to plant regular grass seed in the fall in order to stabilize the new topsoil and then put in the zoisia plugs in the spring?  And the big question: What do you think of Curlex?  We need something to "hold" the soil in place while the grass roots get established.  Curlex has been recommended, but it is SO expensive and such a pain to deal with.  Is there an alternative to Curlex? What would you do? And is it more practical to do this yard in phases, rather than the whole thing at once and risk losing a huge chunk of money? I know I have a lot of questions, but my husband and I are at wits end about this lawn.  We want to make the right choices.

Answer
Curlex Blankets are very effective and time tested.  And yes they are expensive.  Another option is Hydro-seeding -- this is becoming a popular way to establish new Lawns.  It is often unnecessary -- no one needs to Hydroseed flat ground -- but for your property, this may be a perfect solution.   For hills and slopes, it rivals sod for effectiveness.

The process involves spraying the ground with a mixture of Water, Grass seed and growing medium, as though you were
spray-painting the land.  Special equipment is needed; don't expect everylandscaper you reach to be able to offer it.  I have a feeling that in your neck of the woods, being one of the more progressive and affluent counties in the country, several gardening services will be familiar with it.

Sod is another choice you can think about.  But you have less control over the Grass variety -- that may not be an issue for you, but I am a control freak and I like to pick out EVERYTHING myself.  Sod also gives you ZERO control over the chemicals they use to purify their Turf before it rolls out onto your yard.  Me, that's a deal breaker.

There is also the issue of not having the Soil you need to grow a healthy plot of Grass.  Your Soil is what's going to determine whether or not your Grass succeeds long term.

Here's what I would do.

Fix your Soil.  It sounds like you would have better luck growing Grass on the Lunar Surface.  Don't look for a shortcut here.  Your Grass needs a place to live, and you have not got a place it can call Home yet.

That means getting a Soil test right away, dumping a layer of something like Humus or Aged Manure or Compost, perhaps growing a nice Green Manure -- maybe a crop of Alfalfa.  Yes, Alfalfa.

Here's why.

New construction is ALWAYS a problem when it comes to a new Lawn.

Sometimes the only thing you can do is truck in some topsoil.  So you find all kinds of people ready to sell you dirt.  Yours happened to wash away.  Most of the time, this topsoil is filled with Weed Seeds.  I mean, why WOULDN'T it have Weed Seeds in it?  It's topsoil.  They don't bake it or treat it to get rid of the Weed Seeds.  Why should they?  You'll buy it no matter what they include.

Most people end up with a beautiful house surrounded by Weeds growing in expensive Topsoil.

But some people don't buy the Topsoil.  They look at what they have and they work with it.  Sometimes they're just too broke to do anything else -- they would buy Topsoil if they could, but they can't afford it.  So they live with their scarred, scarified real estate, the rocks and rubble, and clean it up instead.  They take out the rocks and the rubble, they amend the Clay, they remove the debris (trees and weird plants) and they wait.  And in a year or so they grow their first plot of Grass.

What you might consider doing is spending the year turning the topsoil (which could be ANYTHING) into dark, nutrient-rich Earth.  And the first step is to get yourself a good Green Manure -- my favorite being Alfalfa.  

Alfalfa is a Cool season perennial legume that goes dormant in the winter.  Alfalfa roots reach up to 12 FEET DOWN into your soil and draw nutrients UP to the surface, where your Grass will be using them.

Univ of Colorado Coop Ext devotes a full page to growing Alfalfa:

www.ext.colostate.edu/pubs/crops/00537.html

They point out that 'Phosphorus is the most limiting nutrient for Alfalfa production'.  Alfalfa also has a 'high sulfur (S) requirement, which results in occasional deficiencies when it is grown on soils low in organic matter.'  Remember that.

Colorado's Agriculture Dept wrote the book on growing Alfalfa. And with a good reason.  Alfalfa happens to be their most valuable forage crop; annual sales hover around $233 million.

Pesticides may not directly target Legumes.  But they will destroy them.  So don't use them.

Fungicides are toxic to Rhizobia bacteria.  Each Legume needs a different species of Rhizobium and Bradyrhizobium to turn atmospheric Nitrogen gas into Ammonia Nitrogen, a form that the plant is able to use.  These good Rhizobia bacteria actually pull 'broken' Nitrogen out of the air and 'fix' it.  This work is done in the Nodules formed along the roots of the Grass.  Destroy the bacteria, and you can kiss the plants goodbye.  You may think that most of our air is Oxygen - but in reality, 78 percent of the air is Nitrogen (N2) gas.  So having 'fixed' Nitrogen is very important.

One critical micronutrient for this Nitrogen fixation is Molybdenum.  Sandy soil, acidic soil with a pH reading below 6.0, or a soil with high readings of Manganese and Iron are generally found to have limited Molybdenum available.  Your Clay Soil WON'T have that problem.

If you are patient and you spend a year with these Soil conditioners, you will be growing Grass a year from now in soil with incredible organic content, excellent soil structure and superior microbial populations.  That will give you a year to decide if you want to splurge on the Curlex, the Hydroseeding, Sod, or even a groundcover.  Zoysia may work for you since it is a very low maintenance Grass that does not need watering.  Get a State of the Art Zoysia bred for drought tolerance to get your money's worth.

Clover, Alfalfa, Wheatgrass, can be a Green Manure.  Specialized Cover Crops that put nutrients and organic matter into your soil, and make space for Oxygen-loving microbes.  Grow your Green Manure this Fall, and then grow it next year, all summer long.

Next FALL, in September 2008, mow down the Green Manure and add Lime as determined by your Soil test, then sow your Grass.

That's what I would do.

Your thoughts invited.  Thanks for writing.