Does Clay Soil Need Lime, Aeration, Or Nitrogen?


Clay soil is one of the most common types of soil in the world. Although clay has a lot of nutrients, the particles are so compacted and dense that they keep the nutrients from getting to where they need to be to help plant growth.

Clay soil can benefit greatly from aeration and nitrogen, but lime is only needed if the soil’s pH level is low. Lime does not help clay soil in any other way. Adding compost (organic material) is also a benefit to clay soil, as is sand. But sand does not have the nutrients that compost does.

Aeration and adding nitrogen and organic material to your soil are the best options for making clay soil better for planting gardens as well as for a healthy lawn. Keep reading to learn some of the best ways to aerate and add nutrients to your soil.

What is Clay Soil?

Clay soil is one of several types of soil you will find in your yard. The best soil to have is loam, and that is what you are trying to achieve when adding nutrients or aerating your existing soil. Loam is an even mixture of the three types of soil:

  • Clay
  • Sand
  • Silt

To determine what kind of soil you have, you can test it with a testing kit or just use one of the simple homemade tests like making a ball or seeing how long of a snake or ribbon you can make from the compacted soil. Or you could try the jelly jar test for a more precise answer. Keep reading for more about these tests.

Making a Ball

Also known as the “poor man’s test,” all you have to do for this test is get a handful of soil and dampen it with water. It should not be dripping wet, just wet enough to squeeze. If the ball crumbles, you have sandy soil. If it forms a ball but falls apart when you touch it, you have silt. But if your ball stays together tightly, that is clay soil.

How Long is Your Ribbon?

Just like the previous test, grab a handful of soil and get it wet. Then make a ball and try to make a long ribbon of soil. The longer the ribbon you can make, the more clay you have. Anything over two inches means you have clay soil.

The Jelly Jar Test

This jelly jar test is an easy test too, but it takes a bit more preparation and time. However, it is a more precise way to tell what kind of soil you have. The items you are going to need include:

  • A jelly or mason jar with a lid
  • One tablespoon of powder dish detergent
  • Permanent marker
  • Ruler
  • Water

First, fill the jar about 1/3 full of soil and fill the rest of the jar with water, leaving about a half-inch of space on top. Add the detergent, put the lid on the jar, and shake it until the contents are completely mixed up.

Let the jar sit for one minute, and then use your marker to mark where the sand is at the bottom of the jar. After leaving the jar undisturbed for two hours, mark the top of the next layer, which is silt.

Leave the jar alone for 48 hours, and then mark the top of the next settled layer, which is the clay. Use the ruler to measure each layer and the total of all three layers. You want your soil to have equal levels of each type of material. But if the clay is thicker than the others, you have clay soil.

Here’s a quick video to show this process from start to finish:

Aerating Your Soil

Your first step in making your soil more habitable for grass and other flora is to aerate. You should aerate compacted soil twice a year, once after your ground thaws and again during planting. There are three different ways to aerate your lawn:

Core Aeration

This is only good if your soil is not heavy clay. If you have a minor clay problem, you can use a core aeration to cut and remove small cores of soil from your yard. They sell core aerators at any lawn and garden store.

Liquid Aeration

This is actually the best choice for clay soils since it works faster and it penetrates deeper than your spikes can go. There are many types of liquid aeration materials on the market, or you can make your own.

First, use a garden fork to create holes every eight inches. Then, place a two-inch layer of newspaper on top of the soil, followed by about a foot of compost or other organic materials. Then you will mix the following products together to make a solution to pour onto your compost.

  • ¼ cup of instant tea granules
  • ½ cup of ammonia
  • 20 gallons of water
  • One 12-ounce can of beer (any kind)
  • One 12-ounce can of cola (any kind)

Pour this mixture onto the top of your compost and newspaper pile and leave it until the next spring. You should then have about eight inches of healthy soil to use for planting.

Spike Aeration

You can do this with a pair of spiked boots or a small lawn spike in small yards or rent a larger spike aerator from a lawn and garden store for a larger lawn. Spike aeration is actually the least effective way to fix clay-compacted soil.

Adding Nitrogen to Your Soil

Besides aeration, you can use compost or some other organic material like manure to add nitrogen for a better soil texture. The best choice is compost from a compost pile that you may have in your yard. If not, you can buy compost or manure to use instead. But do not just put the manure on your soil. You have to mix it to compost first.

Here’s a quick video with some tips for adding nitrogen to soil:

Do Not Waste Your Scraps

In case you are not familiar, compost is just your garden and food waste. Most gardeners have a compost pile in their yard where they toss old, dead plants and food waste. Anything from old fruits and vegetables to dried-up flower arrangements can be used. Anything that used to be alive is a good compost material.

Used Coffee Grounds Work Well Too

Another way to add nitrogen is to use old coffee grounds. Use old coffee grounds to mix directly into the soil. It may take time, but it helps drainage as well. You can use your own discarded coffee grounds or get them from friends and neighbors.

Try Old Fish Parts

If you have any spoiled fish or leftovers from last night’s seafood feast, grind them up and mix them into your soil. Fish is an excellent natural fertilizer and has a lot of nitrogen. If you fish, you can use the scales or skin as well as the insides to add to your mixture. Fishbones and fins work well too.

Buy Some from the Store

You can also buy plant fertilizer from your lawn and garden store. Whether you choose organic or chemical fertilizer, they both work the same. Just look for the first number to be the highest in the NPK ratio because N stands for nitrogen.

However, adding too much nitrogen is not good for your soil either. So, it is best not to use all of these ideas at once. Just try one and see how well it works. If it does not do the trick, try another one next year. No matter what you decide to use, just do not use too much.

One Final Note

On a final note, the best way to handle your clay soil is to loosen it up, and this can be done with aeration. You can do it yourself with an aerator or try some of the liquid aerator solutions. Either way, your clay soil will be much easier to use for gardening after a good aeration.

Robert Sampson

I'm Robert Sampson and I live in Colorado where I spend a lot of time in the backyard with my family either grilling, playing games and sports, or working on a project to make our backyard a better place to be.

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