Gardening Advice

How to Improve Sandy Soil

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Whether you’re a new or experienced gardener – you have to admit: gardening in sandy soil can be challenging. Compared to clay soil, the sandy type is easier to work with, but every “Pros” list has a negative side. It’s coarse and dry, and guess what – so will be most of your plants if you don’t put some effort in moisturising your garden. And we don’t mean watering.

Apart from relocating to another area, there are more than a few ways to make sandy soil fertile. You can use minerals, composts or go creative with coal dust. Below, you will find several different approaches to solving your “sandy” problems – each with its own pros and cons.

Table of Contents:

What is sandy soil and why should you improve it?

Sandy soil can be found along coastlines and near arid and semi-arid regions of north-western plains. Cities like Perth are especially prone to it. It gets better around Sydney, Melbourne or Brisbane. Nevertheless – they are next to the beach, which makes sand hard to avoid.

Sandy soil is perfect for crops like watermelons, peaches, peanuts and many more thanks to their drainage properties. But that isn’t always a good thing. Better drainage means water doesn’t stay in the soil. And less water means there are fewer nutrients. On top of that, every time it rains, or you water your garden, more and more nutrients get rinsed, causing some plants to grow poorly.

Unfortunately, there is another downside – sandy soil is mostly acidic with a pH ranging between 4.5 and 6.0. Most plants thrive in soils with only slightly acidic pH – between 6.0 and 7.0. Many flowers love drier grounds, but, if you wish to expand your crop variety, you’re probably stuck wondering how to make sandy soil fertile. There are several ways to improve sandy soil, so it becomes nutrient-dense and moist enough to feed even the hungriest of plants.

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How to improve sandy soil

When it comes to improving the quality of your soil, there are numerous methods you can use to approach the problem. Some solutions for your garden include organic fertilisers or composts, others introduce more innovative ways of increasing your soil’s water retention and nutrient capacity.


Vermiculite is an excellent choice for the sandy soil in your garden. It can enrich sandy soil and help plants absorb other minerals and electrolytes like calcium, potassium and magnesium, or you can use it to boost your potting soil blend. Vermiculite is a natural mineral product with a 7.0 pH. It has a low density as a soil conditioner for sandy soil, and it’s easy to mix with other growing mediums. On top of that, vermiculite has an excellent water-holding capacity and working with it is easy.

Vermiculite can last up to two years before you have to reapply. And if you use it in potting soil, vermiculite can last a lot longer without breaking down or decomposing, making it a long-term solution for your potted plants. Here is what to use it for:

Seed germination

Vermiculite can be used alone or in combination with soil to improve seed germination.

  • Mixing it: When you plant your seeds, fill the pots with a soil mix of 50% vermiculite.
  • Using it alone: As soon as the first leaves appear, water your seedlings with a diluted soluble fertiliser solution(15mL per 3.5-4L)

Vermiculite is sterile, so you wouldn’t have to worry about damping off.

Garden soil

You can add vermiculite directly to your garden soil:

  1. If you’re seeding your lawn, mix vermiculite with soil and add the seeds.
  2. Spread the mixture evenly and then cover with a layer of vermiculite on top. That will ensure your new plants have increased germination speed, and their roots have better access to nutrients and water.
  3. If you just wish to amend your soil, spread a thin layer(5-6cm) and water with a fine spray.
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Plant transplants

Vermiculite provides a lot of space for roots to spread because it’s lightweight. It helps you control moisture levels, protecting the roots of the plant from drying out.

  1. Dig a hole deeper than the roots of the plant you’re moving.
  2. Mix a part of the topsoil you just removed with vermiculite at a ratio of about 70% soil.

You can also use it as mulch around some garden plants, like roses.

Potted plants

You can save a lot of time by reducing the need to water your plants and eliminating the chance for water spills. An even mix of soil and vermiculite in your pots will improve aeration, too. A neat trick for improving the soil for your flowers:

  1. Fill a pot with vermiculite.
  2. Fill up with water and let it saturate.
  3. Pour excess water out.
  4. Mix the saturated vermiculite with soil and add the plant you’re transplanting.
Vermiculite can hold its weight several times in water, so be sure to add enough when saturating.

Peat moss

Peat moss, also known as Sphagnum moss, is a genus of about 380 species of different mosses. Decayed and dried sphagnum moss is used as a soil conditioner for sandy soil because it can increase water retention capacity and nutrient density. It has an acidic pH between 3.0 and 4.5.

If you plan on gardening in sandy soil, peat moss can benefit the growth of azaleas, hydrangeas, daffodils, rhododendrons and many more. If you’re wondering how to improve sandy soil for that perfect garden flower bed, peat moss is an excellent choice – it can last for a couple of years.

Most of the time, peat moss needs to be mixed with other ingredients in order to provide the best results. On the good side, it won’t cause any damage to your current plants, like a weed outbreak, or a microorganism invasion. You can use peat moss to:

Support acid-loving plants

  • Spread 3-4cm of peat moss around the base of acid-loving plants.
  • Cover that layer with a bit of compost, and you will keep their soil acidic and fertile, just as they love it.
It’s a good idea for plants that require highly acidic soil to first plant them in pots containing a half-peat moss/half-compost mix. After they grow large enough, move them to your garden and apply the steps above.

Fix garden soil

Just spread a thin layer (2-3cm) of peat moss around your garden during your seasonal single dig. That way you get it under the top layer of soil in your garden right where it needs to be to help roots.

As we mentioned above, peat moss on its own isn’t going to do much to help your soil unless it’s highly alkaline. When it comes to sandy soils, which are already pretty acidic, you need to exercise caution. After all, you should turn sandy soil into good soil by helping it retain water, not poisoning the plants.


Biochar is a charcoal substance created by burning organic waste (a.k.a biomass). It has an acidic pH between 3.0 and 12.0, but when it comes to sandy soil – it has an alkaline effect, amending sandy soil and helping your plants grow. Biochar’s high porosity also helps create natural habitats for microorganisms, beneficial to your plants. And the best thing about it – no animals or insects found in gardens eat it, so once you add it to your soil, it will stay there.

The thing that makes biochar a great sandy soil improver is its ability to increase your soil’s CEC – Cation Exchange Capacity. In layman’s terms, the capacity to hold nutrients. This makes fertilisers a lot more effective because they would last a lot longer before you have to reapply them.

If you’re wondering how to make biochar, here’s what to do:

  1. Dig a hole in your garden
  2. Put a mixture of dried plant materials like weeds, roots or sweet corn stalks and dry wood.
  3. Set it on fire. Once the smoke turns from white to grey, cover the fire with some dirt, leave a little space for air and give it some time to char.
  4. Use a hose to put out the charcoals.
  5. Put the charcoal in a bag and use a hammer to crush it to dust.

You can use it by:

Mixing biochar organic matter

  1. Mix one part biochar dust with three parts manure of any kind.
  2. Give it a few weeks to “supercharge”.
  3. Spread it around your garden.
If you want a more potent effect – dig the mixture about a shovel deep into the soil.

Another decent organic mix with biochar is… urine. Yes, you heard right – a nitrogen-rich liquid that is not hard to get hold of. Mix your biochar dust with urine in a barrel or another container. Give it a couple of weeks. Disperse freely.

Applying biochar only

If you want the best results with biochar, then it is advised to dig it into your sandy soil. Just spread a layer of 4-5cm on top and start shovelling. If you don’t have the time or energy to spare – it’s okay, just let it sink into the ground on its own. It would take a few weeks, so check the weather forecast and don’t disperse it on windy days.

Mushroom compost

Another good sandy soil improver is mushroom compost – an organic plant fertiliser with a 6.5 pH and a slow-release rate. Mushroom growers make compost from organic materials like seed husks, poultry litter, horse manure, straw, hay and others, but there are various recipes.

Mushroom compost is usually available at most garden supply stores, and you can use it as a soil improver for sandy soil. It is a no-brainer if you’re on a budget and its benefits include soil enrichment and water-retention increase. There is a slight downside – mushroom compost ph is 6.5, but it can increase the salt level in your garden soil, so use it responsibly. You don’t want your seedlings or salt-sensitive plants to die for that row of perfect tomatoes, right?

How to use mushroom compost:

  • When it’s fresh, mushroom compost can be used as an effective mulch, since weeds have a more challenging time growing in it.
  • If you can afford to wait, it’s always a good idea to stock up on mushroom compost before winter and have it “cure” during the cold season.
  • Mushroom compost can soak up a lot of water, just like vermiculite. Be mindful when you mix it with your regular compost because it can retain too much water and have you end up with overly-moist soil. When you use it in your garden, make sure you don’t mix more than 50% of mushroom compost with soil or regular compost. For potted plants, only mix 25%.

In conclusion, sandy soil provides space for roots, but is bad at feeding most plants or retaining sufficient water for their daily needs. There are various ways to change that. Whether you choose minerals, moss or organic fertilisers, there are many easy ways to increase your soil’s overall fertility. Of course, if you decide that intense backyard terraforming is beyond your capability – do not hesitate to call a professional.

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  • Always remember: sandy soils tend to be acidic – don’t overdo it on low-pH supplements.
  • Don’t try to replace the soil in your garden, either, by overusing composts and fertilisers.
  • Increasing your soil’s water-retention capacity does not substitute regular watering.
  • Vermiculite and mushroom compost are mostly neutral on the pH scale.
  • Making biochar involves lighting a fire. Safety should always come first.
  • Peat moss isn’t very effective alone and has low pH – save it for acid-loving plants.
  • Mushroom compost can increase salt levels. Be mindful when adding it to sensitive crops.
  • In case you don’t feel confident with certain gardening jobs, don’t hesitate to call us.

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Did you learn something new from this article? Which approach do you think would be best for your garden? Make sure to tell us all about it in the comments section below!

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