How Much Compost

[buzzyb]

Evening all,

Can anyone tell me how much compost I will need to buy to fill a planter measuring 180cm x 45cm x 45cm.

Should I add broken pots etc in the bottom to help with drainage?

Thanks

Buzzy

[boxtops]

I can't help with the volume, but you need to make sure that there are holes in the bottom of the planter in the first place, before you fill it, so excess water will drain out - and yes, the broken crocks are a good idea.

[woofgang]

What are you putting in it? I find it harder to keep my planters wet than keeping them drained. Don't whatever you do put polystyrene in the bottom, it makes them top heavy

[Old_Geezer]

I recall reading somewhere recently that broken crocks are not as efficient as folk seem to think, but it doesn't hurt to use them. As for compost, my advice if buy a sack, fill pot as required. Put excess in garage for next time. The pot you describer sounds quite small so a small bag would probably be sufficient if you are keen not to spend more now. But you can judge it by eye anyway. Maybe take the pot with you.

[Frank97]

Small, at 6' long?
I make that approximately 365L of soil required.

[New Judge]

It's actually quite a big planter and will take about 365 litres of compost to fill. As a guide a large bag of compost from the garden centre is usually about 60 litres so you'll need about six of them. Larger ones are available but they are quite heavy to handle.

[EcclesCake]

Closer to 36l I think......

[Frank97]

36L would only fill 2 buckets.

[EcclesCake]

I was visualising a 70l bale of compost.....admittedly not very well!

I do think that 5 bales would be excessive taking account of crocks for drainage, displacement from root balls, aeration of compost and not filling to the top.

[New Judge]

As a check, in "old money" the planter is about 6 feet long by 1.5 feet by 1.5 feet. This is 13.5 cubic feet. There are about 6.25 gallons in a cubic foot, so 13.5 cubic feet is about 84 gallons. At 4.5 litres to a gallon this equates to about 378 litres - a fair approximation to the metric calculation.

[Frank97]

It did sound a lot to me, I must admit, but that's what the maths says.
Think you're right though about the plants and the crocking taking up some of the volume.

[maggiebee]

A tip from my local nursery was to half fill pots with broken up polystyrene such as used in packaging. Weighs next to nothing so pots are easier to move around, while still giving plants enough compost to grow in.

[woofgang]

maggi its fine if the planters are heavy and the plants are low growing. If you have any height at all and the pots are lightweight, it makes them top heavy and they will blow over in a light breeze.

[Old_Geezer]

Ah, not sure how I managed to be a factor of 10 out there. Probably this use of cm I suspect. I still say get a sack (or two) then. Buy more if it proves needed. Store any excess.