Garden Soil vs. Mulch (What Is The Difference?)


If you are hoping to have a great garden this year, you will need to use both garden soil and mulch.  But what is the difference between the two, and when should you use them?

So, what is the difference between garden soil and mulch?  Garden soil is cultivated by gardeners for growing plants, while mulch acts as a soil cover.  Garden soil has been improved with compost or aged manure to add nutrients and organic material.  Mulch helps to retain moisture, prevent erosion, and insulate soil against temperature changes.

Let’s get into more detail about each of these gardening essentials and when to use each one.  We’ll also answer some common questions about garden soil and mulch.

What is the Difference between Garden Soil and Mulch?

The main difference between garden soil and mulch is that garden soil has been carefully cultivated by gardeners.  Garden soil is a mixture of top soil and organic material from compost or manure.

To learn more about the difference between top soil and garden soil, you can read my article here.

On the other hand, mulch is used to cover garden soil or top soil.  Mulch is not worked into the soil, but instead rests on top of the soil to cover it.

Mulch comes from either natural or man-made materials, such as:

  • Wood chips
  • Sawdust
  • Leaves
  • Grass clippings
  • Straw
  • Cardboard
  • Paper
  • Compost
sawdust
Sawdust is just one of many types of mulch.

Mulch makes gardening much easier because it will:

  • Retain moisture in the soil (this prevents plants from drying out in hot weather)
  • Prevent soil erosion (wind and water cannot carry away precious garden soil that is covered by mulch)
  • Insulate soil (prevents temperature fluctuations when it gets cold, so plants can survive a late spring frost or early fall frost)
  • Prevent weeds from growing (it is more difficult for weeds to gain a foothold and establish themselves because many kinds of mulch are not easy to grow in)

What is Garden Soil?

Garden soil is the type of smooth, well-draining, nutrient-dense soil where vegetables (and other plants) will thrive.  Garden soil is crafted over time by taking ordinary top soil and improving it.

Some gardeners carefully cultivate their garden soil for years on end by:

  • Sifting the soil to remove debris (like rocks, sticks, roots, and soil clumps)
  • Adding compost or aged manure (to add organic material and nutrients)
  • Adding supplements (such as fertilizers) to provide extra nutrition or adjusting pH (using lime or sulfur)
  • Rotating crops every year (to avoid nutrient deficiencies and plant diseases in the soil)

What is Garden Soil Used for?

Garden soil can be used to fill plant containers such as pots and grow bags.  Well-cultivated garden soil provides an ideal environment for mature plants after they pass the germination and young seedling stage of development.

radish seedlings
Use potting mix, rather than garden soil, when starting seeds indoors. This helps to prevent disease and other problems.

When germinating seeds indoors to grow seedlings, you should use sterile potting soil instead of garden soil.  This reduces the chance that diseases, mold, or other problems will affect your plants.

Can You Use Garden Soil in Raised Beds?

Yes, you can use garden soil in your raised beds.  As long as you improve the soil with compost or aged manure, you plants should grow well.

Soil in a raised bed will drain better than the soil in your garden, due to the extra elevation.  As a result, you may want to use raised beds for gardening if your soil drains a little slowly.

supported raised bed
You can use garden soil in a raised bed, and put a layer of mulch on top of it if you like.

To learn more about why to use raised beds and the types you can choose from, check out my article here.

What is Mulch?

Mulch is used as a top layer in your garden to cover the soil.  It is not worked into the soil, but rather it rests on top of the soil to provide protection from weeds, cold, and erosion.

You can usually tell what mulch was made from just by looking at it.  For example, you can tell whether mulch was made from wood chips or leaves (at least, before it decomposes over time).

What is Mulch Used for?

Mulch has several uses in the yard and garden, all of which will help your plants to grow better.

Retains Moisture in Soil

A layer of mulch over garden soil prevents water from evaporating quickly on a hot, dry day.  This keeps plants alive for a just a little longer during droughts (or if you forget to water them!)

Since mulch helps to retain moisture in soil, you will not need to water quite so often. 

Prevents Soil Erosion

Wind and water can carry away garden soil or top soil, along with the precious nutrients they contain.  Over time, this can have a devastating effect on the quality of your garden soil.

A layer of mulch will hold the soil in place, preventing erosion in your garden.

Insulates Soil

Adding mulch to your garden also helps to regulate soil temperature.  Mulch does this by acting like an insulator.

On hot, sunny days, the mulch will heat up before the soil below.  This prevents your plants from getting too hot too quickly.

On cold days, the mulch will trap heat, meaning that the soil below cools down more slowly.  This prevents late spring frosts or early fall frosts from damaging or killing your plants.

Prevents Weeds

Weeds are just like any other plant in your garden, except for one thing – you don’t want them around!  Otherwise, weeds need water, sunlight, and nutrients, just like any other plant.

If you can deny them these resources, they will have trouble growing.  Mulch does just that, by covering up the seeds of weeds and preventing them from getting water and sunlight.

weeds
Weeds are just plants you don’t want – they can be killed in the same way as any other plants.

Since mulch is not completely decomposed, it will not contain as many available nutrients as garden soil.  This also makes it more difficult for weeds to grow.

If you already have weeds growing, you can put down a layer of mulch to smother them with heat or lack of sunlight.

Can You Use Mulch in a Vegetable Garden?

Yes, you can use mulch in a vegetable garden.  It makes a good addition to the soil when it decomposes.  In the meantime, it provides all of the benefits listed above.

You can use the following materials as mulch:

  • Wood chips – this is often what people think of when they hear the word “mulch”.  It can be expensive to buy it by the bag, so consider ordering a bulk delivery from a local landscaping company.
  • Sawdust – if you know someone who owns a saw mill, you can probably make a deal to take the sawdust off his hands for a low price.  Be careful about using sawdust from pressure-treated wood, since the chemicals can leach into the soil and then into your vegetables.
  • Leaves – this is a common type of mulch that many people overlook.  Even those who use leaves often turn them into compost, rather than using them as mulch.  However, a layer of leaves on top of your garden soil will prevent weeds from growing.  They will eventually decompose and add nutrients and organic material to the soil.
  • Grass clippings – this is another common mulch that many people overlook.  You can use grass from your own lawn, or from a friend’s lawn.  Grass clippings can smother weeds if applied over your garden soil.  Grass clippings also have lots of nitrogen, so they will add a nutrition boost to the soil when they decompose.
  • Straw – you might find straw, along with manure, at a local horse boarding place.  If you buy straw bales to do straw bale gardening, you can use the leftover material as mulch.
  • Cardboard – this is another common mulching material that people overlook.  It will eventually biodegrade, but in the meantime it can prevent weeds from growing – or smother ones that are already there.  Watch out for cardboard with staples in it!
  • Paper – similar to cardboard, but it will probably break down even faster.
  • Compost – compost is most often mixed into garden soil to improve it by adding nutrients and organic material.  However, you can use compost as mulch to smother weeds.  You can then turn the whole mix into your soil after the weeds are gone.
cardboard boxes
Cardboard is one option for mulching your garden. You can disassemble and flatten boxes to give you a thick layer, or tear them up into pieces.

There is one important thing to keep in mind: it is possible to use too much mulch.  Too much mulch will kill plants, and improper application can even kill trees.

To learn more about how to use mulch properly, read my article on mulch here.

What is the Best Mulch for Gardens?

Leaves and grass clippings are the best mulch for gardens.  They are both widely available, and you can get them cheap or free.

When leaves and grass decompose, you can work them into the soil to add nutrients and organic material.  You can then add more leaves or grass clippings as mulch, thus repeating the cycle.

Conclusion

Now you know the difference between garden soil and mulch, and what each one is used for.  You also have some ideas about what to use as mulch in your garden.

I hope you found this article helpful – if so, please share it with someone who will find the information useful.  It’s time to get back out to the garden to tend to your soil – don’t forget the mulch!

jonathon.david.madore

Hi, I'm Jon. Let's solve your gardening problems, spend more time growing, and get the best harvest every year!

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