Topping potted plants with sand has many benefits, including improving the water-draining qualities of the soil, adding weight to the light potting mix, and supporting the plant structure.
However, it's not very effective to resolve the fungus gnats problem. The sand doesn't prevent them from breeding and laying eggs in the potting medium.
Still, you can add sand to the potted plants. Check out the following guide to learn more about the benefits of using sand for houseplants.
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Can I Put Sand On Top Of My Potted Plants?
As mentioned above, you can certainly put sand on top of your potted plants.
But you shouldn't use it as a primary potting soil for houseplants. The sand doesn't contain beneficial nutrients for the plant's growth and drains out most essential elements from the pot in less time.
According to Utah State University, soil with more than 70% sand is not appropriate for plant growth. This is due to the sand's poor nutrient and water retention capacities.
Although sand doesn't hold water for long, you shouldn't use regular sand (fine sand) for the potting mix. For this purpose, you should opt for horticultural sand. It is coarse and does a great job leaching out excess water from the pot.
Tip: Adding more organic materials can improve the sandy soil quality.
How To Use Sand For Potted Plants
There are two ways you can use sand in your potted plants, i.e., mixing it directly with the potting mix or spreading it on the topsoil. Both these methods produce similar results, so you can choose any of them as you like.
Let's look at these methods briefly.
- Mixing In The Potting Mix - In this method, the sand becomes a part of the entire potting mix. This allows you to prepare a potting mix of your choice and set the proportions accordingly. Since sand doesn't offer many nutrients, you can limit its quantity to 20-25% of the soil mix.
- Using It As A Topsoil Layer - Many people believe adding sand on top of the soil helps prevent fungus gnats, but that's not true. However, if you still want to try it out, add a layer of horticultural sand to the pot. The proportion should be the same for this sand as well. But if you're not sure about it, add a small layer of sand to it.
Here's a demonstration video of how to use sand and potting soil properly -
Types Of Sand To Use For Potted Plants
Selecting the right type of sand is necessary for potted plants. If you choose the wrong one, your houseplants might suffer and exhibit a lack of growth.
Here's a list of sands that are suitable for plants -
Horticultural Sand: It is the most useful sand for your potted plants. Horticultural sand consists of small and medium-sized particles, which enhance water drainage in the pot.
You will easily find this sand in any online shop and nearby garden center. It is mainly known as coarse sand and gardening sand.
Don't forget to rinse the sand before use, though!
Builder's Sand or Construction Sand: If you can't get hold of horticultural sand, you may use construction sand for the potted plants. Although it possesses more fine particles than horticultural sand, it's still coarse enough to drain water from the pot.
Similarly, you will have to rinse the sand properly before use. This type of sand will have many chemicals and unwanted elements that might hurt your plant's roots. So, putting it under the water and removing harmful components is better.
Silica Sand: This can be another alternative if you don't find the other two sands in your area. Silica sand is a mixture of fine sand and coarse particles.
It does help in rooting and can be used as topsoil for potted plants.
Refer to the following table and learn about appropriate sand types for plants.
| Sand Type | Particle Size | Suitable For |
|---|---|---|
| Horticultural Sand | 2-5 mm | Indoor Plants and Succulents |
| Builder's Sand | > 4.75 mm | Indoor Plants and Succulents |
| Silica Sand | 1-2 mm | Succulents |
| Play Sand | 2 mm | Not Suitable Plants |
| Beach Sand | 0.25 mm - 2 mm | Not Suitable Plants |
Note: Beach sand is not beneficial for plants. It has a very fine texture, which is not effective for root growth. It will also not hold moisture content for long and leach out the necessary nutrients from the pot.
Expert Tips For Topping Potted Plants With Sand
Here's what you need to remember -
- Don't go overboard and add too much sand to the potted plant. You should only add a handful of sand to the pot to improve the drainage quality of the soil.
- Use sand with a grain size of 2-4 mm. This type of sand is perfectly coarse and allows quick water drainage. Don't use aquarium sand.
- Rinse the sand before using it in the soil. Although it's not necessary, the sand may sometimes contain unwanted elements that may harm the roots.
- Use it only for succulents and draught-tolerant indoor plants. Regular flowering or fruiting plants prefer nutrient-rich soil, so sandy soil won't benefit them.
Using Sand To Get Rid Of Fungus Gnats
Many gardening enthusiasts believe that using a layer of sand on top of the soil can help eliminate fungus gnats. However, that's not true!
These bugs will find their way to lay eggs on the soil, and sand can't help much in this situation.
The only thing you can do here is to stop overwatering the plant. The gnats don't like dry surfaces, as they thrive on wet soil surfaces. So, if you truly want to succeed in getting rid of these bugs, work on the watering schedule.
Also, indoor plants don't require frequent watering. Water them once a week or so.
Note: If the fungus gnats are wreaking havoc in your home garden, use a neem oil spray. You may resort to commercial insecticides as well. They give similar results.
What To Put On Top Of Potted Plants?
Here's a list of mediums you can use as topsoil -
Sand
Even though sand is not too beneficial in itself, there is not much harm in using it in a limited quantity. You can also use it for rooting purposes, as the smaller plants don't require many nutrients in the early stages.
When using sand as a potting medium, the water should drain in 5-10 seconds. If not, you are using sand with very fine particles. This type of sand is not good for your plant's growth.
Organic Matter
It is probably the best option for topping the soil of potted plants.
Organic matter provides essential components for plants and is useful for indoor and outdoor plants. With a layer of organic matter, the indoor plants will exhibit significant growth in stems and leaves.
Moreover, you can also add homemade compost to the soil. It will be beneficial for your plants too.
Pebbles
Pebbles are another interesting component for potted plants. They add aesthetic value to the pot and also help drain the water.
But there are a couple of downsides to using pebbles in the pot. When you add them to the pot, it automatically increases the weight of the pot.
Apart from that, they don't add any nutritional value to the soil. You will separately need to add compost or balanced fertilizers to the plant.
FAQs
It depends on the type of plants you're using it for. You will need to select the plants appropriately to use sand as one of the potting mix ingredients.
Sand doesn't kill plants. However, it depends on how you use it in your home garden.
If the proportion of sand quantity is more than recommended, the plant will not get sufficient nutrients and will show a lack of growth. Over time, it may stop showing any growth signs and perish in the process.
Yes, the sand can support plant life, but you must transplant it to a better potting medium at some point.
Plants like well-draining coarse sand. Horticultural sand offers these qualities and is recommended by many plant experts.
As explained earlier, sand doesn't prevent fungus gnats issues. You should only use sand if the soil lacks drainage quality.
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