How to calculate how many pebbles I need for my pots?

[Cottontree55]

i need some pebbles for my balcony pots. The area is 0.033232 cubic meters. How much pebbles do I need. I have white pebbles in mind, 4 cm. Deep.

[EricL]

Hello @Cottontree55 

Welcome to the Bunnings Workshop community. It's fabulous to have you join us, and thanks for sharing your question about pebbles.

If the area you've calculated is 0.033232 in cubic meters, well need to convert this measurement into litres. You can either multiply it by 1000 or move the decimal 3 places to the right. This will give us an amount of 33.232 litres and when converted to kilograms it is exactly the same. Hence 33.232 litres is 33.232kg.

There are quite a number of white pebbles available at the store. If we round up the amount to 34kg and the white pebble bags come in 10kg bags you would conservatively need 4 bags which is more than enough to cover your needs.

If you have any other questions we can help with, please let us know.

Eric

[Jason]

Hi @Cottontree55,

Welcome to the Bunnings Workshop community.

I trust you found Eric's reply helpful. I just thought I'd add in case you weren't aware that not all plants are going to prosper if you add pebbles to their pots - particularly if they are in the sun as the pebbles will retain heat. If you'd like to let us know what you are growing, we would be happy to provide further advice. 

Thanks,

Jason

[Cottontree55]

Thanks EricL,

just the advice I needed. 

[Cottontree55]

Thanks Jason, the pots in question have these 🪴 , Diamantina Agatha, Hibiscus. But the pots don’t get any sun in the summer, like from now on, but are on a north facing balcony. Is that OK?

Thanks.

[Jason]

Let me tag the wonderful @Noelle for her thoughts on what you are growing @Cottontree55. 

I would happily use pebbles for succulents, but not much else. 

Jason

[Noelle]

Hi @Cottontree55 

Just be aware that 34 litres of pebbles will weigh a lot more than 34kg - 1 litre of water weighs 1kg but with heavier products like pebbles 1L will weigh more than a kilo. Similarly 1L of feathers will weigh a lot less than 1kg. Litres are a measure of volume while kilos are a measure of mass.

I'm with Jason here in that pebbles are really only suitable for use on the top of pots of cacti and succulents, not shrubs and other plants like your hibiscus. Their presence in a layer over the top of the pot will inhibit the free movement of air into and through the potting mix - plants roots need good aeration to thrive. Pebbles will also compact the potting mix, depending on how deep a layer you use. Compaction also reduces air circulation around the roots.

[Cottontree55]

Thanks Jason and Noelle for the advice. It’s much appreciated. I have been trying to buy and get the pebbles most of the day but haven’t managed it yet. I am elderly and getting lost on the internet + delivery cost is too much. Given your advice I will have to go back to the drawing board. Reason I wanted to use pebbles was we get a lot of wind on the balcony and it blows the compost all over the floor. So have you guys got a simple solution to stop that happening? Thanks 🙏.

[Noelle]

Hi again @Cottontree55 

If the potting mix in the pots is watered regularly, as your hibiscus may require, then the top surface should never really be dry enough to blow off the pots.

You may, if you wish, use a thin layer (1-2cm) of coarse washed propagating sand, like the gritty sand used in the bottom of fish tanks, to provide enough cover to prevent wind-blown soil but make sure it is not too deep. This product is available from Bunnings - click on the link above.

[MitchellMc]

Hi @Cottontree55,

Are you able to visit a store at all? I trust our team will gladly load your vehicle with your required sand/pebbles. Getting it out at the other end might be more difficult. Any friends that could assist?

Mitchell