Should you add sand to garden soil? The pros and cons


There is a lot of useful information out there on whether sand should be added to garden soil. After researching the topic, I’ve written this article to weigh up the pros and cons.

You can add sand to garden soil, but it has to be mixed to certain proportions. If the soil and sand are mixed incorrectly, it results in denser, heavier soil. For clay soil to become sand and lighter, the soil must consist of fifty percent sand.

We will be covering the possible benefits and disadvantages of doing such in the following sections, so do read on.

Adding sand to your garden soil

If sand is added to garden soil in small amounts, it will make hardly any difference to the overall mixture. Ideally, the soil should have 50% pore space. In clay soil, the pore spaces are tiny. Sandy soil, on the other hand, has larger pore spaces.

Mixing the sandy soil and clay soil causes the larger spaces of the sand to be compacted and filled in with the minute particles of clay, and the result is dense, heavier soil with a smaller pore space than either of the materials.

Essentially, all life depends upon the soil… There can be no life without soil and no soil without life; they have evolved together.

Dr. Charles E Kellogg, Soil Scientist and Chief of the USDA’s Bureau for Chemistry and Soils

For the soil to take on the properties of sand, the ratio of the two materials would need to be close to 50:50. This would be impractical and very costly in many cases, but it is a good way to make your garden soil finer and lighter if you have a small garden space or patch of soil.

Clay soil and garden soil, what is the difference

We’ve been mentioning clay soil and garden soil a few times now, and we would like to take this chance to introduce them properly in this article.

Clay soil is considered one of the more prevalent soil types, especially in the United States, and it has tiny particles that allow it to be a very compact type of soil.

While they have the ability to hold many nutrients and water, it is not advisable to use for fostering plant growth. More about them is covered in detail in this article that I wrote on clay soil and its usage for plant growth, which you can check through here.

Garden soil, on the other hand, which is another word for topsoil, contains good nutrients that are very productive for plant growth, especially when well taken care of and often aerated.

They are usually found at the first 2 to 8 inches of soil, and more about their descriptions are described in another article that I wrote on garden soil and its components, linked here.

That being said, clay soil is covered extensively and often mentioned in this article because it is often one of the most prevalent topsoil components. Hopefully, these explanations will lessen confusion throughout the article.

When & why you should add sand to garden soil

Sand can effectively create pockets of air, increasing aeration, drainage and generally loosening up the soil. This is especially helpful for plants with fine wire roots, such as lettuces.

Essentially, you want to add sand to garden soil to improve the drainage, make the mixture lighter, or stop the soil from clumping and being too compact.

Despite all of its good qualities, you can’t just add sand to any soil.

Add sand only to compost and not to native soil

Pure compost is, generally speaking, the only type of soil that you should add sand to. Adding sand to native soils isn’t a good idea and will actually be detrimental to your garden in many cases.

When sand is used with clay, it will cause the soil to bind and become even more compacted. The aeration will then be reduced, having the opposite effect to what we desire.

In years gone by, it was common advice to add sand to garden soil to improve the consistency. As more has been learned about soil structures, textures, and the ways to improve these attributes, it has become clear that there are many more effective ways to help garden soil than the addition of sand.

Misconceptions about sand in connection to soil

It’s a widespread misconception that sand is good at breaking up clay. I can see why people would come to this conclusion because the particle size of sand particles is much larger than clay particles. The issue isn’t with particle size, though.

Clay is technically an alkaline chemical bind that includes lime, and the bonded chemicals within the clay are impossible for the sand to break up.

As I mentioned above and is very effective when used in conjunction with pure compost. It is important, however, to be aware of a few things. Because sand helps to improve drainage, a process called leeching can occur.

What is leeching and what can it do to your soil?

Leeching is when the water pulls nutrients away from your plants. This occurs because most nutrients and minerals are water-soluble, although there are some exceptions. Potassium, phosphorus, and nitrogen can all be found in water-soluble forms.

When it rains or you water the garden, the water begins to pull the nutrients away from the plants.

The added sand into the soil has served its purpose in speeding up the drainage process, but simultaneously the plants have been deprived of nutrition due to the increase in leeching.

Thankfully, there is an easy way to combat this. Fertilizing one or two more times during the season will ensure an abundance of nutrients and minerals available to the plants. The leeching process won’t be as detrimental to their overall health.

For the most part, if your soil is organic and rich in nutrients, you probably shouldn’t add sand, as it has the chance of exacerbating any existing issues. Pure compost, though, can be an effective way to improve the consistency and drainage properties.

When & why you shouldn’t add sand to garden soil

Now that we’ve established the situations in which sand could benefit our garden soil let’s look at the reverse. In truth, adding sand to garden soil can be equally detrimental as it can be beneficial, depending on the specific circumstance.

Sand minimizes the amount of moisture that the soil can hold. If the volume of sand and clay are equal, this will result in the clay dramatically increasing its ability to hold moisture by around fourfold.

This is a good option for those with a smaller area to fill, but mixing your whole garden to be 50% sand is unrealistic.

Adding sand in small amounts have no benefit to the soil

It would be wise to err on the side of caution when it comes to applying sand. Despite there being much common misinformation on the topic stating that it is beneficial, it could damage your garden soil further and impact your garden’s efficiency.

Adding small amounts of sand should be avoided completely. There’s no benefit to doing this, and it is likely to exacerbate any pre-existing issues.

With high-quality compost, sand can be useful when added. In this case, it should be used in conjunction with frequent fertilizing because the nutrients and minerals may be lost due to the leeching process.

Comparisons of particles of clay and sand

Despite their small size, clay particles dominate in soil. Thanks to their size, more clay particles can fit into space, so their overall surface area is larger than any other material within the soil.

Sand particles are much larger than clay, so fewer particles are required to fill the same space that the clay would fill with many particles.

The result is that sand has a much small overall surface area and, therefore, when compared to clay, has much less of an influence on the soil’s properties and characteristics.

Never add sand to prairie soil

I can categorically say that adding sand to prairie soils is never a good idea. The addition of small amounts of sand may seem harmless, but in fact, it can be worse than adding larger quantities to your soil. This is due to large sand particles mixing with the minute clay particles and resulting in a concrete mixture.

Remedies for dry clay soil

If your specific reason for adding sand to your garden soil is the soil being heavy and claylike, this section will focus on detailed ways to remedy this problem and prevent it from reoccurring.

We’ve established that sand isn’t an effective way to solve it, but some tried and tested processes will lighten the garden soil and make it better for growing.

Mix organic matter into your clay soil

The best way to lighten clay soil is to mix it with a lot of organic matter. If possible, you should create a layer of at least four inches consisting of compost, manure, leaf mold or mulch, wood chips, and so on.

When the compost, manure mulch, and all those decompose, the resulting humus will create space within the clay particles and allow air to get in.

Water will also move through the particles more easily, resulting in lighter garden soil in its consistency.

Topping up of organic matter of your clay soil is recommended on a regular basis

This is an ongoing process, so you need to continue adding the organic matter regularly. The reason for this is that the matter will decompose over time, so you need to keep topping it up.

The results from the first addition of organic matter will have a greatly positive impact on the garden soil, though. It will become lighter and easier to garden with every addition due to the nutrients from the mulch going into the soil.

Adding soil to soil

If you want a quicker alternative to using sand or organic matter to improve the quality of your garden soil, this might be the method for you.

Instead of putting in the time and effort mixing organic matter into hard, heavy soil, you could take a more simple approach. By adding a substantial layer of good quality garden soil over the clay soil, you can use this later for your gardening purposes.  

Benefits of clay soil

As much as I have berated clay’s ability as a surface soil in this article, it actually makes a perfect bottom soil (subsoil).

Clay soil has good mineral and moisture-retaining capabilities, and it holds onto those and then releases them to the plants above.

Using good-quality topsoil with clay soil as the base can actually be a highly effective growing environment that will improve your garden.

Interestingly, this mixture is likely the way your garden was before the house was constructed. When a house is developed, the topsoil is usually removed, leaving soil that is clay-heavy and difficult for plants to grow in. So by adding a layer of high-quality topsoil, you could say the garden is going back to its roots!

More effective alternatives to boosting your garden soil rather than using sand

Thankfully, you can employ other more reliable methods to solve the issues with your garden soil. These techniques are more efficient than using sand and pose less of a risk if they go wrong.

Let’s look at some of the ways to improve the poor draining and aeration properties of garden soil without sand.

Use mulch is one way of boosting garden soil

Using mulch prevents the soil from compacting and improves the overall aggregate structure.

Mulch is a handy tool for gardeners and is free! Its use results in less need for weeding, less watering, less frost damage, less compaction of soil, and overall improvement of plant health.

Plant-based, organic mulches will break down into healthy soils as time goes by. Simply spreading around five inches of organic mulch onto your garden soil will work wonders. Some great materials to use for your mulch mixture are; shredded bark, peat moss, leaves, grass clippings, compost, manure, and wood chips.

Keep your tilling to a minimum to better your garden soil

Avoid tilling your soil too much.

It is true that digging and tilling initially break up the clumps of soil and make the consistency more fluffy, but once the garden soil settles, it will become more and more compact and cement-like.

The only way to combat this is to add large amounts of organic matter every time you till the soil. Tilling when the soil is wet is hugely detrimental to its consistency and can really damage the structure. If possible, gardening without tillage is the ideal scenario.

Look into using peat moss to boost your garden soil

Using peat moss is an effective way to break down garden soil. It works because it is very absorbent and holds water in the soil for longer durations than many other materials.

Be wary though, if your garden soil is very claylike and thick, adding peat moss could end up making the problem even worse.

FAQs

Conclusion on should you add sand your garden soil

Be sure to establish the needs of your garden soil before deciding on what approach to take, whether be it by adding sand or other materials. If the soil is clay-like and clumpy, the remedy will differ greatly from if the soil is too moist or struggling to drain properly.

We have discussed many alternative methods that provide the same benefits to your garden soil without posing a risk. My personal favorite is making an organic mulch layer on your garden soil. This is a great way to use leftover materials.

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Tony O'Neill

I am Tony O'Neill, A full-time firefighter, and professional gardener. I have spent most of my life gardening. From the age of 7 until the present day at 46. My goal is to use my love and knowledge of gardening to support you and to simplify the gardening process so you are more productive

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