I recently purchased a new construction home. The backyard came unfinished and the yard is sloping away from the house.

From what it looks like, the yard is subsoil, it looks like it's essentially all the stuff building debris/rocks scraped off the land when the developers were building/grading the foundation.

Grass obviously can't grow on this so I assume I will need tons of topsoil prior to grading/seeding (4 inches?) I live in the Pacific Northwest so we get a lot of rain during the winter season so erosion and runoff is generally a concern on a sloped backyard.

I recently finished spraying glysophate 41% (roundup) on the whole yard, I expect it to die out in a week or two. I assume I need to pull all the weeds out prior to adding the top soil, I will also have to remove the large rocks/roots/general debris from the subsoil.

My question is, should I be tilling the subsoil prior to adding the topsoil? If so, how much inches? Or should I be adding the topsoil then tilling it directly into the subsoil?

Any recommendations or techniques on how to make the topsoil stay on the sloped hill?? It's roughly 30-40 degree slope.

Any advice is greatly appreciated. My end goal is to have a grass seeded in September.

edit: Pictures here - https://i.stack.imgur.com/1vSpi.jpg You can see how the fence slopes to get an idea of the hill. I plan on putting a garden bed on a majority of the slope with trees/shrubs/mulch and maybe have stairs to the right of the house. The picture of the dirt was with the rake, I pretty much can't really "dig" at all. Water does pond up on some parts from what I have seen.

  • Welcome to the site qsub. This is a great first question, with lots of details that will help us help you. Would you also please post a picture or two so we can see the slope and what the soil looks like now? Thanks! Jul 17, 2017 at 19:18
  • @qsub digging out all the rock and debris from the subsoil is usually not necessary. You gotta send a picture. I built custom homes. Dumping the debris on site is a huge no no and under certain circumstances that contractor is still liable, especially if he was paid for debris removal within his bid. Send pictures. This is the time to make that landscape work for you and improve the value of your home. Grass seed is better than nothing to get through the winter!! If I was low on my budget that is what I would do. A sloped yard done correctly will be far more valuable than a flat yard.
    – stormy
    Jul 17, 2017 at 21:53
  • A lawn shouldn't need "tons of topsoil". With adequate top dressing and aeration you should be able to grow a nice grass from seed or turf. It would be preferable to remove the larger rocks/debris first though (depending on size and quantity). Pictures would really help!
    – Viv
    Jul 18, 2017 at 0:55
  • @stormy Perhaps it's not debris, but its just a ton of huge and small rocks along with stuff like broken tree trunks. But as mentioned my main concern right now is getting some vegetation and having proper setup so runoff doesn't occur when it rains. Any other changes to the landscaping itself would be long term and not immediate as I don't have much cash flow or time to put towards this. I'm doing it alone basically.
    – qsub
    Jul 18, 2017 at 3:44
  • @Sue pictures have been added
    – qsub
    Jul 18, 2017 at 3:46

1 Answer 1


Really need to get an idea of slope. Use Rise/Run = Slope. Lawn is not always the easiest way to create a decent landscape to support the value or increase the value of your home.

You do not need to till the new topsoil into your subsurface soil. You may not need topsoil at all. I've seen sod grow quite well and for a long time ON GRAVEL.

Making tiers with your sloped land is fairly easy, inexpensive and very interesting! If you sent me an as-built with at least 3 elevations I could help with grading. You are very lucky to have your soil slope away from your home. You could easily make a few garden walls; less than 18" high, that would be gorgeous and solid and usable.

Please send pictures. Look for your 'As-Built' that should be in your mortgage paperwork.before

after You do not have to go to this extreme...but this client's home DOUBLED in value with this landscaping.

Grass/lawn is not the only option but a very inexpensive way to to do something with your land so you don't have a muddy site for this winter. I'd have a seed company spray your entire property for grass and that will at least make it not muddy and unfinished...that works very well. You do not want to mess with your soil except for finish grading. The grass seeding company can help as well.

Then when you are able you really need to do a bit of professional work.

  • That's a pretty hardscaping job. But one of the reasons it made the value of the home go up was because of the labor and resources involved (which is significantly higher than even the best seeding and lawn care plan). Most people would not have the budget for that.
    – J. Musser
    Jul 17, 2017 at 21:02
  • People put just as much money into materials and labor for wood decks that didn't do a thing for the value of the home. The important part is this transition from the home (same level) and weight! Extra 'rooms' are added into the living spaces. To have built a huge deck connecting their little wrap around to the back door would have been MORE expensive and labor intensive for maintenance. Weird, huh! Seeding his soil is fine but it isn't landscaping. That is why I told him to check out a seeding company to spray and take care of the raw soil. When he can afford to do more...
    – stormy
    Jul 17, 2017 at 21:38
  • Just garden walls, .DIY, with these CMU products would make a far more usable landscape. I always design for a project to be done in stages...have some flexibility.
    – stormy
    Jul 17, 2017 at 21:40

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