How to Grow Grass on a Steep Hill

By Brian Mounts | Mar 23, 2020
How to Grow Grass on a Steep Hill

Do you want to grow grass on a steep hill on your property? There are several steps that need to be taken to be successful, but with a little extra preparation, it is no different than seeding a regular lawn.  The biggest challenge to overcome with growing grass on hills that have a decent grade is preventing erosion during the germination and early growing phases.  This can be mitigated by following my step by step process for seeding and growing grass on a steep hill.

Challenges of growing grass on a steep hill?

  • Seed can simply roll downhill leaving bald spots if the grade is too steep. If all you do is follow traditional steps for overseeding a lawn you will end up bare spots and a ton of wasted grass seed.
  • Consider using grass plugs. These come in flats just like vegetables come from a plant nursery.  They are rooted grass and can be popped out of the trays and planted just like any other plant that you buy from the store.
  • Look for erosion control grass species. Grass varieties that establish quickly like tall fescue are perfect choices to quickly grow grass on a steep hill.

Essentials for Growing Grass on Any Grade

  1. Heat – You have to wait until the weather warms up from the winter before seeding or utilize the slightly cooler early fall months as too much heat will dry out the soil and make establishing freshly planted plugs or seed very difficult.
  2. Seed contact with the soil – All seeds must be on soil to successfully germinate. If the hill you are planting has lots of leaves or other debris due your best to clear the area before planting.
  3. Sun – You need good light to quickly grow grass. You can consider doing a little light pruning if you are planting new grass seed if several large trees are blocking all of the light on the area that you want to establish a turf lawn on.
  4. Water – Plan to irrigate the newly planted / seeded area everyday in order to be successful. Without sufficient water the lawn will not get established at all or be very spotty requiring you to come back through a second time to fill in the bare spots.  Avoid overwatering grass seed especially on a hill as it will cause erosion problems.

Step by Step Process for Seeding and Growing Grass on a Steep Hill

  1. Remove any vegetation in the way with a shovel or rake. Start at the top and work your way downhill to make pick up and removal easier.
  2. Till the soil with a tiller or cultivator like a hoe if the grade is steep you may not be able to effectively use equipment. A hoe will allow you to control the work and avoid having dirt tumble downhill.
  3. Add your soil amendments and press them into the ground if you don’t make sure they are applied and pressed they will just wash off in the first good rain or when irrigating the new seed.
  4. Add a layer of compost to get additional organic material into your soil. It is best if this can be tilled in or worked into the ground with a cultivator or hoe. Like the other procedures start from the top and work down.  This is a good time to add in nutrients like phosphorus if your soil is deficient.
  5. Irrigate the soil so that it is wet, but make sure not to drench it. You do not want to create a landslide so avoid getting it wet enough to create mud.  Better to go lighter on the water than heavy if the grade is steep.
  6. Create holes using the end of your hoe upside down or using a small shovel or trowel every 6 to 12 inches along the peak of the hill.
  7. Continue to work downward staggering your holes as you go until you reach the bottom.
  8. Fertilize the hill by placing a little bit of granular starter fertilizer in every hole. You may not be able to run a fertilizer spreader, so it is best to just manually get a little everywhere you plan to stick a grass plug. Again, use starter fertilizer not a general grass fertilizer.
  9. Push in a grass sprig / plug into each of the hole.
  10. After placing in the hole press the soil around the plug firmly to hold it into place.
  11. Place seed down along with the plugs. In order to improve your success rate, I recommend to also highly consider adding in seed.  You will want to over seed as some of the seed will move down hill and not every seed will always germinate.
  12. Apply a thin layer of peat moss on all of the areas that you have applied seed.
  13. Cover the hillside with an erosion control mat made out of jute and secure it so that it does not blow away in the wind. Use stakes that along all of the edges to keep it in place.  This will ensure that the hill side does not erode while irrigating and establishing the turf grass.
  14. Water every day for the next two weeks, you can skip a day if it rains but make sure that the ground stays moist. This will ensure the grass plugs get fully established and will thrive. Use a garden hose connected to a sprinkler to evenly apply water versus manually spraying the area.
  15. After a few weeks you can remove the erosion control mat if the one that you used is not biodegradable. I would highly recommend using an erosion control mat made from Jute.  This will allow you to place seed along with your plugs and not have to worry about pulling them out when the mat is removed as you do not need to remove it all.  Simply pull your stakes and allow it to decompose right in the lawn.  The grass will grow through and it will disappear over the course of the season.

Selecting the Seeds: This is Important

Once you have the entire place prepared, it’s finally time to sow seeds, right?

Not really. You still don’t know which seeds you want to sow!

Quoting TheSpruce:

Deep-rooted “bunching” grasses work well on hillsides.

Some top choices among these non-turf grasses include Little Blue Stem (Schizachyrium Scoparium), Prairie Drop Seed (Sporobolus Heterolepis), Sideoats Grama (Bouteloua Curtipendula), Blue Grama, (Bouteloua Gracilis), Wavy Hairgrass (Deschampsia Flexuosa), and Indiangrass, (Sorghastrum Nutans).

Now, it’s time to choose the kind of grass the seeds of which you want to sow. There are quite a few things you might want to keep into account while choosing them, like:

  • The slope of the land: The slope of the land is one of the essential things that you must consider. Several varieties of grass actually happen to be better or worse at growing at particular levels of steepness.
  • The chemical composition: As I just remarked, the chemical composition of the soil must be considered. This is because the kind of grass depends a lot on the composition of the soil. While you can use fertilizers, sticking to the grasses that naturally are adapted to such a composition are always the better choice.
  • The overall climate: Naturally, not all kinds of grasses grow everywhere, so it’s essential to know what grows where you want to plant it. To sum it all up, you need to actually do your research before you jump in to plant the seeds.

Now, if you are careful when choosing the seeds, and if you finally make a good choice, things will be easier now on. This is simply so because you’re trying to grow what naturally does grow there. So, while you can actually do otherwise by applying fertilizers, it is really recommended to stick to the natural vegetation there.

See my full grass growing guide here for more helpful tips – no opt-in needed.

How to decide if growing grass on a steep hill is right for your lawn?

If you are having erosion problems than it is important to get it under control before big problems start that will require expensive repairs and mitigation that only can be done by trained professionals.  Grasses are an excellent way to control erosion and keep the soil locked into place.

Consider creating a small ditch as an outlet for the water to be funneled along and down the side of your property away from the area that you want to grow grass.  However, be very aware that directing the water to a specific area without erosion control measures will result in more erosion problems.

By creating a small depression that is filled in heavily with rocks you can create a channel for the water to flow off the side of the hill and away from the grassy area.  The rocks will stay in place and act to slow down the speed of the water as it flows.  This will help the water to slowly disperse into the soil as it moves down the hill.

If the hill is very shaded, consider doing some light pruning in the tree canopy to allow more light to come into the area.  Prune trees if you must, but do not cut trees down on a steep hill as the roots of the tree are doing an excellent job of keeping the soil from eroding. If the area is too shaded for grass to grow it is wise to consider if grass is the best solution. Planting out native vegetation that works well in shade may help you prevent erosion and build habitat for the birds and bees in your area.  Make the wisest decision for your own steep hill, grass can be excellent option and of course the answer for people with kids that are looking for a safe place for them to play.

In Conclusion

Take the time to plan for growing grass on a steep hill and everything will work out well.  Utilize grass plugs and overseed the area with your seed of choice.  Water lightly, but consistently to allow it to establish and use a biodegradable erosion control mat and everything will turn out well.