Sand has been lauded as one of the valuable soil amendments to use for improving drainage. But what if you’re fresh out of horticultural sand and only have a nearby river to source your sand from?
River sand contains little nutrients, has low water-retention capability, and may also contain unknown contaminants that are detrimental to your plants. It is often better to use horticultural sand instead and limit the use to container gardening.
If you decide to use river sand in your garden, it is important to mix it with other soil amendments to ensure that it provides adequate drainage and nutrients for your plants. You may also want to test the pH and salt levels of your soil regularly to ensure that the river sand is not causing any problems.
River sand also comes in many different levels of coarseness, not all river sand is the same. Make sure the sand you’re using is the right kind for the plants you’ll be amending soil for. Cacti may prefer a heavy mix of coarse sand – plenty of water drainage. Meanwhile, plants needing less drainage may prefer smaller grains and less sand. Llike ferns.
Below, I elaborate more on this, along with helpful tips for using sand in gardening:
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Can I Use River Sand in My Garden?
Coarse sand is a great substance used for improving drainage and encouraging better root growth in plants. However, there are certain situations where it becomes more harmful than beneficial.
Let’s look at sand as a whole. We know that it drains water freely because of its large and jagged particle size, creating multiple air pockets which allow water to run through quickly. But despite its high permeability, sand cannot hold on to water or nutrients for long. This is why when adding fertilizers to sandy soil, it’s best to do it more often in small amounts to keep the plants nourished.
Conversely, clay particles are smaller and readily clump together, eliminating air pockets. Water takes longer to pass through because the substance retains it too well. With that in mind, it makes sense to mix sand into clay soil to make it more well-draining, right?
But it comes with a caveat. You need to add an equal amount of sand to the existing soil, clay or otherwise, to improve the drainage. In an in-ground garden, this is simply impractical and too costly. If you get the ratio wrong, you will end up with a more dense ground akin to concrete.
This is a similar problem in the river sand’s case. If you’re sourcing it from a nearby riverbank, you risk transferring heavy metal components and weed seeds into your garden. Even if you practice sustainable methods of river sand collection, it’s generally not a good idea.
Therefore, it’s not advisable to use sand, including river sand, in an in-ground garden for drainage improvement due to the vast amount needed to balance the soil composition. And despite its origins, it has almost no nutrients to nourish the soil.
It’s way better to add compost to clay or sandy soil for drainage because it will naturally break down and help improve the structure. You can read this composting article to understand just how useful it can be for your garden. But that said, it doesn’t mean you can never use sand, including sustainably sourced river sand, in your gardening …
How Can I Use River Sand in my Garden?
As I mentioned in the previous section, you can’t. Or at least not in a traditional in-ground garden. But you can use it for a container and raised-bed garden because it’s far more manageable.
Simply mix a 50-50 ratio of river sand and potting soil thoroughly before using it for planting or starting seeds. For cacti & succulents, it’s best to add additional aerating materials like perlite to increase drainage. Before use, wash your river sand thoroughly until the water runs clear to remove dust. Where possible, use horticultural sand. It is often more affordable and readily available than river sand.
You may have also come across river sand being given away as ‘free soil’ from a dredging operation in your local area. I recommend stirring clear of this if it’s not regulated or washed. It may contain harmful components that may damage your plants, which is not worth the ‘free’ pricetag.
For those unfamiliar with ‘dredging’, it’s essentially the removal process of sediments accumulated at the bottom of lakes, streams, and rivers. It’s a crucial part of maintaining water channels for maritime purposes. It sadly has nothing to do with coating chicken wings in flour because this is not a cooking blog.
Frequently Asked Questions about River Sand
River sand is often used in construction due to its coarse and jagged structure. Mining this substance has become a big problem over the years, primarily because of the significant demand needed for construction. The issue is that these riverbanks are being depleted of sand too much before it has completed replenishing. This affects the area’s biodiversity and pollutes local areas of their natural water resources.
This is why it’s best to use river sand sourced from a reputable seller with good sustainable practices. While it is not recommended for in-ground planting, it can be used in container gardening like potted plants and raised beds to improve drainage.
River sand is a great addition to a potting medium filled with equal parts of peat/coir. However, it should never be used as a stand-alone soil because succulents will not get enough water to get through dry periods. This is especially important if they are potted because they depend on us for their watering needs. Though if they are placed outside where they will get saturated with occasional rainfall, it’s okay.
River sand does not have any nutrients that are beneficial to plant growth. Due to their low water retention capability, they cannot hold on to nutrients for too long, regardless of how high in mineral content their origin is. It’s better to add compost or use a diluted liquid fertilizer to give plants a pick-me-up every once in a while.
River sand is ineffective and of no use in maintaining or improving a lawn. It may worsen drainage problems by making the ground more compact, especially if it’s a large area. If it is a small area, it may be doable to use river sand, provided it is mixed in equal amounts to the existing soil.
Horticultural sand differs from river sand in composition, mineral content, and texture. It is often used primarily for gardening, while river sand is more commonly used in construction. Using horticultural sand helps improve drainage for container gardens, but not in-ground planting.
Overall, river sand is not necessarily the best sand choice for gardening. You’re better off using readily available horticultural sand for your container gardening needs. Happy planting!
- Rentier, E. S., & Cammeraat, L. H. (2022). The environmental impacts of river sand mining. Science of the Total Environment, 838, 155877. https://doi.org/10.1016/j.scitotenv.2022.155877
- Baking up a better soil makes for a successful garden. (n.d.). Newswire.caes.uga.edu. Retrieved August 25, 2022, from https://newswire.caes.uga.edu/story/7718/soil-mixes.html
- Free Soil | Growing & Mowing in Bartow County. (n.d.). Site.extension.uga.edu. Retrieved August 25, 2022, from https://site.extension.uga.edu/bartow/free-soil/
- Does Sand Improve Clay Soil Drainage?: University of Illinois Extension. (n.d.). Extension.illinois.edu. https://extension.illinois.edu/blogs/good-growing/2018-01-31-does-sand-improve-clay-soil-drainage
- Improving Sandy Soils. (n.d.). Pender.ces.ncsu.edu. Retrieved August 25, 2022, from https://pender.ces.ncsu.edu/2022/02/improving-sandy-soils/
- Soil Amendment for Lawns and Landscapes | Nebraska Drought Resources | Nebraska. (n.d.). Droughtresources.unl.edu. Retrieved August 25, 2022, from https://droughtresources.unl.edu/soil-amendment-lawns-and-landscapes
- Choosing a Soil Amendment – 7.235. (n.d.). Extension. https://extension.colostate.edu/topic-areas/yard-garden/choosing-a-soil-amendment/