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Lawn & Garden

Need advice on digging up St. Augustine grass and building a deck

Can you offer advice?

I live in Southern California and hired someone to physically dig up my St. Augustine grass because it was so ugly and the dirt/ground needed to be regraded for drainage purposes.  The workers only took the sod / St. Augustine up, and did not dig down into the ground and remove dirt even though they used a sod cutter.

I don't want to use RoundUp or any other herbicide.  How many inches down do I need to remove soil in order to prevent St. Augustine regrowth?

Once that's done, how should I prepare the soil in order to seed a new lawn?  I'd love to use bluegrass seeds, but some people at Home Depot tell me that's crazy and I should only attempt to plant a fescue lawn.  I want to plant and water seeds and am willing to wait a month or so for them to pop up and fill in.  What do you think I should do?

Also, I'm thinking about taking the dirt that is dug up (to remove the St. Augustine roots and to regrade the backyard) and using it as fill dirt for a higher deck that would be bounded by bricks (say 1-2 laid sideways) and that would have Home Depot's rustic 12 x 12 inch concrete pavers on top.  That way I could basically lay the pavers on top of fill dirt and set them in masonry sand without the need for pouring any concrete.  I recently removed a broken concrete patio and have had enough concrete to last a lifetime. 

Any thoughts/guidance you can offer would be greatly appreciated!

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Posted 2016-01-17T06:07:41+0000  by NightWarrior NightWarrior
Hey NightWarrior.

My first thought was that if you are living in an area that St. Augustine grows, then you are in too hot of a climate for Kentucky Bluegrass. The Home Depot sells a product called Heat-Tolerant Bluegrass but it is absolutely not going to tolerate your climate. Bluegrass is less tolerant of heat than fescue.

What is your soil like?

Very sandy soils will be tough for Fescue or Bluegrass to grow in, as they are heavy feeders and sandy soils are not very nutrient rich. Another issue is that the sandier the soil, the deeper the root system has gone with your St. Augustine. Sod farms simply topdress their Bermuda and St. Augustine fields with a couple of inches of a sand/dirt mixture so the roots will come back up to form grass again. Because of this, I would think that you would have to remove at least the top 4 inches of dirt to get rid of roots.

I see that you are just South of LA. I think the only options as far as grass is concerned would be centipede, Bermuda or St. Augustine. My team from LA will chime in with their thoughts tomorrow.

Posted 2016-01-17T18:37:03+0000  by Ingar_HD_ATL


Hi NightWarrior.


Thank you for your question and welcome to our Community.


Ingar is right on, but there is still more work to do for you.

St. Augustine is actually a great grass to have, providing you take care of it.  The root system of the St. Augustine can go as deep as 6-8 inches, depending on your soil.  I have the St. Augustine in my front and back yard.  It is a great high traffic grass and very durable with pets and kids. 


Now that you have removed the top layer of your St. Augustine, the area you plan on having pavers installed in should be Ok.  The area where you plan on having your new grass planted may be a problem source down the road. 


When preparing the soil for new seed out here in Southern California where we have lots of sandy loam and sandier type of clay soil, you will want to amend your soil with a good quality garden soil.  Being on the West Coast, we have access to a great product by Kellogg called “Garden Soil”.  By using a higher quality soil, you will be able to reduce the number of weed seeds to your soil. 


For best results, add 2-4 inches of Kellogg Garden Soil to the top of your intended lawn area and rototill it in to a depth of 4-6 inches.  Fescue is actually a great grass for Southern California in that it will stay green all year long since it does not go dormant in the cooler weather.  If your area does get a freeze for a few days, fescue may turn brown on the tips for a bit but it will survive. 

                                                        3 cu. ft. All Natural Garden Soil for Flowers and Vegetables

The St. Augustine has a tendency to go partially to fully dormant during the cooler months of December thru March, depending on the weather.  Last year was a warm winter and my St. Augustine came back in February when the temperatures climbed in the 80’s.


For the best result, you can use a combination of Kentucky Blue grass and Fescue. The key to a successful new lawn is the amount of seeding that you do.  Do not skimp on the seeds!  Pay attention to the package of lawn seeds.  When it says “Up to” on the package, it means if you apply the seeds sparingly, you may get the coverage listed on the bag.  Do not apply your grass seeds sparingly. You will want to make 3 passes on your newly seeds lawn.  The first pass should cover the perimeter. The 2nd and 3rd pass will cover the interior area.  If you were looking at a rectangular lawn, you would go from top to bottom and from side to side.


Once the seeds have been laid down, your next step will be to cover the seeds with a good quality Topper.  I prefer the Kellogg Topper.  Place a layer of Kellogg Topper about 1/8 to no more than ¼ of an inch thick over the top of your seeds.  This layer will help to keep the seeds damp, help to prevent the sun from drying the seeds out, help to prevent the wind from blowing the seeds away, the rain from washing the seeds away and most importantly, it will deter the birds form swooping in to eat all of your newly planted seeds!   

                                                                  2 cu. ft. Topper Lawn Soil for Seed and Sod

 Since  is already dug up, this is a great time to add your automatic sprinklers.  Be sure to have them water in the morning and never in the evening.  Night time watering can cause a fungus in your lawn due to the cooler temperatures in the evening.


Initially, you can water your newly seeded lawn by hand if you want to since the new seeds are only 1 to ¼ inch from the top of the soil.  You will want to water several times a day if needed to keep the top of the soil looking damp, but not wet enough to cause puddles of water. If Mother Nature helps you, so much the better.  Your seeds should start to sprout in about 7-10 days. You may be able to speed up your seed sprouting by adding a “Starter Fertilizer” after the topper has been applied.  A Starter Fertilizer is high in Phosphate, which will encourage the growth of your new seeds, providing you keep the seeds damp.

                                      15 lb. 5,000 sq. ft. Turf Builder Starter Brand Fertilizer18 lb. 5,000 sq. ft. Starter Fertilizer

Regarding the setting of your pavers over the soil dug up from your St. Augustine, you will want to add at least a 2 inch layer of compacted finishing sand prior to laying down your pavers.  The area of fill dirt should be leveled and then compacted prior to adding your masonry sand or the finishing sand. A layer of weed mat would help to prevent any weeds seeds from taking deeper roots once the pavers have been installed.  

After the area of finishing sand has been compacted over the weed mat, the pavers can be laid down.  The better job in compaction you do, the smoother your pavers will be later on down the road.  Remember, the few extra hours you spend now in preparation, the less aggravation you have later on.


Once the pavers have been set, you will want to use a product by Quikrete called POWERLOC sku# 835229. This is finer sand with bit of mortar mixed in.  It is designed to be swept into the space between the pavers.  This should be available in the Garden Department or in Construction/Building Materials.  For best results, use a tamper with a small kneeling pad to prevent direct contact with the pavers from the heavy metal tamper.  Sweep the product in and then tamp about 3 times to achieve best penetration of the POWERLOC.  

                                       10 in. x 10 in. Steel Tamper Kneeling Cushion

Once this has been completed, lightly mist the POWERLOC into the spaces.  Be careful not to “blast” the water into the crevices. This will only wash the POWERLOC out.  Allow to settle for at least 4-6 hours before walking on it to give the Quikrete a chance to set.  If you can wait overnight, even better especially if it has been cold and damp.  Once the Quikrete has set, it will have the consistance of a hard sandy mortar, but not as dense.  

Be sure to take pictures of your project and share them with us on our community!


Please let us know if we can be of further assistance.



Posted 2016-01-19T23:14:13+0000  by Rick_HD_OC
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