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New Foundation Bed Preparation #861178

Asked March 11, 2024, 8:10 PM EDT

Hello, and thanks for your service!

I'm starting a major landscaping project this spring. My goal this year is to create a three new beds for foundation and ornamental plants. I'd like your input on which new bed preparation method is most suitable for proven long term landscape and ornamental plant health and growth. 

I'm not an "good enough" kind of person, but would rather do it right the first time. But neither do I want to invest my time and effort in a way that will not provide any proven long term benefit.  And that is why I'm asking for your expert advice!

I live in a small house built in 1960 on a 1/8 acre suburban lot in Dearborn Heights.  Based on information from neighbors who have lived here much longer than I have, the house has never had major landscaping done, although there was the building contractor installed "row" of arborvitae directly against the front of the house. Those were removed last year. The only other "disturbances" to the soil to my knowledge was the giant lopsided "Y" shaped trenches carved about a foot deep into the ground into which underground 3" PVC pipes were installed to distribute rain water to a pop up head collected from downspouts on either side of the house. 

I'll have to remove the sod in about 50 % of the area I've designated for this years project. Overall, I've a number of the areas to do, ultimately occupying 90% of the entire yard area. I will only work on one area a year, spending the time creating the new beds in the spring/summer and installing the landscape and ornamental plants for those beds in the fall. If that is advised.    

I have a about .5"- 2" of good topsoil under the sod, before I hit the predominate heavy clay soils.  Those souls go down more than 4 feet.

I've put in numerous small veggie gardens in the past, most using the double dig method. 

However, I've been reading recently about less labor intensive "no-dig" and "no till" methods.  However, these articles seem primarily focused on veggie gardens applications.

Are these two methods suitable for foundation and ornamental planting as well?  

If so, which of these two methods works best for my application?  

Given that the "no-dig" and "no-till" methods construct a new "layer" on the top of the existing soil structure, how soon after creating the bed can one plant? 

Since I don't want to raise the overall finished elevation of the existing soil, is it appropriate to remove a 5" to 6" layer to compensate for the height of the added cardboard and compost prior to using one of these two methods? or does that defeat the whole purpose of not disturbing the existing soil structure?

Bottom line, for my application, and desiring optimal long term results, with assurance that my labor is to in vain, would you use double dig, "no-dig" or "no till", or some other method to create these beds?  

Thanks!


Wayne County Michigan

Expert Response

Hello Danny,

You can certainly use the same method for preparing the soil for an ornamental garden as a vegetable garden. Double-digging was considered useful in the past but in addition to being a back-breaking activity, it breaks down soil structure and disturbs dormant weed seeds that are lying underground waiting for light to germinate. As a result, no-till and no dig soil preparations have become popular.

There are many benefits of a no-till soil including maintaining the soil structure. Read more here: https://extension.umn.edu/managing-soil-and-nutrients/reducing-tillage-your-garden#:~:text=Tillage%20contributes%20negatively%20to%20soil,are%20more%20diverse%20and%20resilient

You can use the sheet mulch technique of mowing the grass as short as possible, covering with cardboard or three sheets of newspaper, damping the newspaper and covering the area with 3-4 inches of compost or shredded mulch. This garden would be ready to plant in six months. The bed will be slightly higher than the lawn. To keep the garden at the same level as the law, you use a sod cutter to remove the lawn, cover the area with 2-3 inches of compost and incorporate it in the present soil. This will encourage the invertebrates in the soil to break down the compacted clay soil that you are planting in. Read more here: https://www.canr.msu.edu/news/soil_compaction_and_what_to_do_about_it#:~:text=Another%20form%20of%20compaction%20is,peat%20moss%20or%20leaf%20mold.

Compost and mulch will help the clay soil break down.

Good luck with your garden.

Thank you for contacting Ask Extension.


An Ask Extension Expert Replied March 13, 2024, 4:58 PM EDT
A couple of follow up questions:

  • Should a leaf, bark or hardwood mulch be applied over the top of the compost if “no-dig” method is used?
    • I know this is standard practice for most types of bed preparation.
  • Since my topsoil is thin in most places, and I expect to be planting 3 to 5 gallon shrubs, if “no-dig”is used wouldn’t that mean that half of the root ball would end up in heavy clay?  Would that not negatively impact the drainage efficiency around and the growth rate of the plant?
  • The landscape plan requires that I remove up to 3"-4” of the existing sod and soil in some areas of the yard to even out the grade/slope.  If the typical 3"-4” of mulch is used on top of the compost, that means that I will need to remove as much as 8” of existing sod and soil.  How does that impact the effectiveness of “no-dig”? 
  • How does "no-dig” improve the hard clay below the topsoil over time?

Just trying to think this through.  I don’t want to waste my investment in the landscape by drowning the plants or seeing a retarded growth because I didn’t prepare the space properly.

I really appreciate your expertise and advice.

On Mar 13, 2024, at 4:58 PM, Ask Extension <<personal data hidden>> wrote:

The Question Asker Replied March 15, 2024, 11:52 AM EDT

Hello Danny,

By adding compost and mulch to a compacted or heavy clay soil, all the invertebrates, such as earthworms, ants, nemotodes, fungus, etc. that live in the soil come into play. They start by tunnelling and breaking down the soil. This loosens the clay and allows plants to grow in it. I have built many gardens by covering the sod with newsprint, watering it and putting at least 3 inches of double shredded hardwood on top. In a couple of months, I can pull back the newsprint and eureka, earthworms, roly polys and other insects are active. They proceed to break up the compost, mulch and clay into nice mineral soil. It is not like building a garden on concrete. Many creatures become active and breakdown the clay and compacted soil. This is the benefit of a no-dig garden preparation. In addition, it does not allow weed seeds to break dormancy. So, you have a lovely weed-free garden. Your new plants will very likely thrive in these conditions. You also may find that the mulch breaks down so efficiently that the next year you need to apply more.

The articles that I sent explain this method of dealing with compacted soils.

Thank you for contacting Ask Extension.


An Ask Extension Expert Replied March 15, 2024, 12:17 PM EDT

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