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 in resolving 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.
So, let's check out the following guide to learn more about the benefits of using sand for houseplants.
Putting Sand On Top Of Potted Plants
As mentioned above, you can certainly put sand on top of your potted plants.
However, you shouldn't use it as the primary potting soil for houseplants. Sand lacks beneficial nutrients for plant growth and rapidly drains essential elements from the pot.
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.
Even though sand doesn't retain water for long, fine sand should not be used for the potting mix.
For this purpose, you should opt for horticultural sand. It is coarse and does a great job of 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. It 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 properly use sand and potting soil -
Types Of Sand For Houseplants
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 -
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.
This is 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.
How To Water Plants With Sand On Top Of Soil
When the topsoil is covered with sand, you can use any of the two methods, i.e., direct watering or bottom watering technique.
1. Direct Watering Method
In this method, you can directly water the plant at the base. There is no need to perform additional tasks, as sand offers excellent drainage properties.
The roots will get sufficient water instantaneously because of the coarse texture of the sand.
If you have placed a thick layer of sand on top of the soil, remove it before watering the plant. It will help drain water from the pot, and you can save the plant from root rot-like issues.
2. Bottom Watering Method
As mentioned earlier, you can also water the plant from the bottom of the pot.
Here's how to do it -
- Place a plate or saucer under the pot.
- Fill it with water.
- Allow the roots to soak water from the base of the pot.
- Water every 4-5 days, and adjust frequency based on your specific plant's needs.
This process is far more convenient than removing a layer of sand from the topsoil. So, do try it out!
- Use a plate or saucer with raised edges. It will help prevent water from spilling out on the floor.
- Use a moisture meter if you're not sure when to water your plants. It will give you accurate data regarding the watering requirements of your plant.
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 -
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.
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 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.
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.