How To Grow Grass In Clay Soil?
Clay soil is not a very good soil for growing lawn grass directly due to very fine particles that retain water and prevent the normal flow of water (soggy soil) and air in the soil.
Also, during dry weather, clay hardens in almost rock-like material and cracks, damaging the gentle roots and drying even faster.
Published: March 4, 2023.
Amend The Soil
Having clay soil should not stop a gardener from growing fruits, veggies, flowers, or lawn grass as desired.
It just means that some extra work, time, effort, and money is required to have a lush, green lawn.
Before considering starting a lawn on clay soil, test the soil using a soil test kit to find out what is missing in the soil in terms of pH and nutrients.
As soil for lawns, the clay is not good since it prevents the normal flow of water and air. Also, grassroots have difficulty penetrating and growing normally, have issues with collecting water and nutrients, etc.
So, before starting a lawn on clay soil, amend the soil in a few simple steps.
Note: When the clay is dry, it is hard to work with - almost rock-hard. When the clay is wet, it sticks to practically anything, and any work with such soil is very difficult. Thus, to start working with the clay, wait until the clay is moist "just right."
Rototill the soil
Run a rototiller over the desired area twice in different directions, and using a rake, remove any remaining roots, rocks, weeds, or similar debris.
Apply organic fertilizer
After turning over the soil and cleaning any remaining debris, apply a thick layer of organic compost, aged manure, dried manure (pellets), and worm castings. Also, adding some "ordinary" potting soil or peat moss can help prepare the soil.
This layer should be at least 2-4 inches (5-10 cm) thick.
Run a rototiller over the future lawn again, mixing the organic fertilizers with clay soil thoroughly.
Note: the more organic fertilizers, the better. Over time, organic matter decomposes and mixes with clay particles, improving water drainage and aeration and feeding the lawn with an almost constant flow of nutrients. Organic matter also promotes the activity of earthworms, improving soil quality even more.
Now, using a leveling rake, carefully level the lawn surface.
Got some extra organic compost? Great - again, add a thin layer (1-2 inches, 2.5-5 cm) of organic compost and till in the soil, some 4-5 inches (10-12.5 cm) deep.
Now, just in case, level the lawn again.
Note: in the future, as the soil settles down and the grass starts to grow, any irregularity can be leveled by adding small amounts of potting soil and compost over a period of a few months.
Now your future lawn patch is ready - it is time to sow the grass seeds or place some grass sods.
Grass Seeds vs. Grass Sods
Grass seeds are easier to purchase and can be stored for some time and used at the right moment.
Grass sods can be in the form of slabs or rolls. For covering larger areas, rolls are more practical, although sod slabs are good as well.
A big problem with the grass sods is timing - grass sods should be collected, for example, in the afternoon and used the next day. If the sods are used after 36-48 hours, most of the grass will simply be dead by then (especially during the warmer days).
But sods enable the gardener a quick start, especially when starting the lawn on a patch of clay soil, even if that soil is heavily amended.
Sowing the grass seeds
After obtaining the desired seeds and preparing the soil, it is time to sow some grass seeds using the following steps:
- Measure your future lawn and calculate the amount of required seeds,
- Sow the seeds either manually or using a seed spreader,
- Gently rake the grass seeds into the soil,
- Roll the patch using a weighted lawn roller (if unavailable, a wooden plank can be used as well),
- Water the lawn gently (use mist if possible).
After the seeds germinate, verify if there are any "bald" spots - if present, reseed them carefully.
Placing the grass sods
Using grass sods, especially rolls, is an excellent method for starting a lawn on amended clay soil.
Put a grass roll on the edge of the future lawn and unroll it. Continue with placing grass rolls next to each other.
Note: If there are some gaps between the rolls, fill them with some loose potting soil - after watering, the water will "pull" the soil into the gaps, and the grass will soon cover the gaps.
After covering the entire lawn with grass rolls, water the grass.
Very soon, the grass will grow new roots into the amended clay (which is by now far from being clay), and the gardener can start with standard lawn grass maintenance - watering, mowing, fertilizing ...
Watering: water moderately, keeping the soil moist and promoting strong root growth.
Mowing: mow at most to medium height. Grass up to 4 inches (10 cm) tall protects the soil from strong sun and wind, keeping the soil moist.
Fertilizing: the soil is rich in organic matter, feeding the newly grown grass. However, from time to time, test the soil and, if required, apply a liquid grass fertilizer.
Also, periodically aerate the soil and remove any weeds competing with the grass for water and nutrients.
Grass Types For Clay Soil
Heavily amended clay soil can be used to grow almost any type of lawn grass. However, some types are better for growing in clay soil than others. Grass types suitable for such clay (or amended clay) soils include:
Other grass types can be used as well, just be sure that the amended soil drains well and is well-aerated and leveled properly.
Note: during colder periods, grass rolls and slabs can be stored for up to 5-7 days, but just in case, use them within the first 24 hours.
Long Story Short: Clay soil is not good soil for starting a lawn, but after amending it with plenty of organic fertilizers, numerous grass types can successfully be grown, especially when grass rolls are used to kick-start the lawn.