Converting Compost Litres to Weight

[jojo2910]

This may be an impossible question, but if anyone will know the answer grapes will. Its also a bit like a maths question.

My neighbour sells compost by the tonne and he sells it for £1.40 per 80L bag. How many bags would you get for a tonne?

Much appreciated.

[Two_Sheds]

Are you filling raised beds or something? And what kind of compost is it?

[Aberdeenplotter]

Litres are a measure of volume (like pints), whereas tonnes are a measure of mass, also often wrongly referred to as weight. So it depends on the density of the substance. If it is water it is easy - 1 litre = 1 kg, so 1000 litres = 1000kg = 1 tonne. A tonne is 1000kg. If you know the density of your substance relative to water you can convert from there. For example if density is 1/2 that of water 1000 litres = 500kg = 0.5 tonnes.

[Aberdeenplotter]

I should maybe confess to having lifted that off a website

[jojo2910]

Are you filling raised beds or something? And what kind of compost is it?

No I am trying to work out if it is cheaper for me and my family to buy a tonne of compost for this year rather than buy the MPC which is on offer. I want to know how many bags we would get from a tonne and how much it would cost. If, for example, its 100 bags then that will be too much, but if it worked out to be 20 bags then it could be better value. I didn't want to get my neighbours hopes up without trying to work it out first.

It is MPC.

Aberdeen plotter if you hadn't said then I would have given you all the credit. Maybe the answer is to weigh a litre of MPC and see what that gives me.

[zazen999]

That is exactly the answer - but it depends also on how wet your tonne will be...the more water the heavier the load for the volume and thus the less volume you will get.

How much does he charge per tonne?

[Aberdeenplotter]

Aberdeen plotter if you hadn't said then I would have given you all the credit. Maybe the answer is to weigh a litre of MPC and see what that gives me.

But then I couldn't have lived with the knowledge that I had plageurised some poor souls work.

Don't know if this helps but I make up my compost for growing exhibition potatoes and then store it in tonne builders bags until I do the planting. Each builders bag filled to the top holds 35 x 17 ltre bags of compost. That is a few litres short of 600ltres or 7.5 x 80 ltre bags.

That comparison is by volume and not by weight so a weight comparison would be useful.

Remember you may have difficulty transporting compost in bulk whereas you can easily move a few 80 ltre bags.

[rana]

How ever many bags make up a ton(ne), £1.40 for 80L of MPC is a real bargain.
Also remember that commercial MPC bags state the volume 'when packed'. Both the volume and the weight change with storage and the state of hydration.

[jojo2910]

How ever many bags make up a ton(ne), £1.40 for 80L of MPC is a real bargain.
Also remember that commercial MPC bags state the volume 'when packed'. Both the volume and the weight change with storage and the state of hydration.

Thanks, I thought it was a bargain too, just need the weekend to work out if I'll be buying 20 or 200 bags.

[jojo2910]

The quote is in... I can get 40 60L bags for a tonne. It will cost about £100 which works out £2.50 a bag. As we can get the Homebase planters for £1.43 we are leaving it at the moment.

[ronymaxwell]

Approximate Values per Tonne

A little research has come up with these approximate values

In each case, the volume in litres is for a weight of one tonne

Screened Topsoil: 750
Blended Topsoil: 900
General Purpose Compost: 1050

This applies to a moisture content as you would expect delivered

[Sarico]

If by ton you mean a ton bulk bag then is difficult. Ton bag are sold by cubic meter. So 1 ton bag of compost could be 600kg and not 1000kg. You should work out for the volume with is 1000l for ton. I know that because I wanted to but a ton of compost and they told me that the ton bag actually weight 600kg considered that compost is lighter. The sand or gravel.

[Bill HH]

There is a vast difference in weight according to the moisture content, A bag of MPC that has dried right out is almost weightless and can easily be picked up with one hand. To pick up a wet bag however is a job for the wife. So it is an impossible question and really involves visual inspection and a judgement at the time.

[Snow]

I found that it is cheaper to buy bags on offer than it is to buy in bulk in a tonne bag. As someone pointed out to me, transport is probably a major factor in why it is more expensive to get a tonne bag.

[ronymaxwell]

Approximate values are useful though. Gravel is another, though varying according to grain size. Generally one 25kg bag of clean 20mm gravel is 14.25L volume.