OK, first things first, you have pots and we need to work out how much soil they will hold. So measure the top of your pot across the widest part and the height of your pot to where you want the soil to go.
This is now the time to cast our minds back to maths class and pull out a few cobweb encrusted formulas.
We need to work out the volume of your pot(s)
The following formula is perfect for a cylindrical pot (a pot with the same size top and bottom). However if you have a tapered pot you will need to adjust it slightly — a quick and dirty (sorry for the pun) solution is to take an average of the top and bottom diameter and plug it into the following formula.
Volume = pi x radius2 x height
So lets assume you have a pot with a diameter of 30cm. This pot therefore has a radius of 15cm.
And let“s also assume it is 30cm tall.
Volume of soil needed to fill your pot = 3.14 x 15cm2 x 30cm
Volume = 21195 cm3
But we need to know how many litres will fill the pot (because the bags are sold in 30 litre bags), so all we need to do is divide 21195cm3 by 1000.
Therefore, Volume = 21.195 litres (or rounded to 21 litres)
Therefore, approximately 2/3 of a 30L bag of Jeffries Veggie & Garden Soil will fill a 30cm wide and 30cm tall plant pot.