GardenCalc.uk · Free UK Field Guide 01

The UK Compost Cheat Sheet

Which compost for which job, how much, and when. No waste, no guesswork.

Which compost for which job

The job	Use this (peat-free)	Why
Sowing seeds	Fine seed / peat-free multipurpose	Low nutrients + fine texture so seedlings root easily
Pots & containers	Multipurpose + John Innes No.2/3	The loam holds water & feed for the long haul
Raised beds & borders	Soil improver / well-rotted manure	You're feeding soil, not filling a pot, so it's cheaper per litre
Blueberries, rhododendrons	Ericaceous compost	They need acidic soil; ordinary compost slowly starves them

How much do you need?

Topping a raised bed: our raised-bed ratio is 30–40% compost over 60–70% topsoil. A 2m×1m bed at 25cm ≈ 150L compost over 350L soil.
Pots: a 40cm patio pot holds roughly 40 litres.
Don't eyeball it. The compost calculator gives your exact litres and bag count.

Peat-free behaves differently

It dries out faster on top, so check with a finger and water a little more often.
It runs out of feed sooner, so start liquid feeding pots after about 4–6 weeks.
Lumpy bag? Normal for peat-free. Break up big bits before sowing fine seed.

The £-saver

Buying the right amount once beats two trips and a half-used bag going hard in the shed. Big beds? Bulk bags of soil improver are far cheaper per litre. And many UK councils sell cheap green-waste compost (fine for beds, not seeds).

📐 Your exact amount in 10 seconds gardencalc.uk/compost-calculator

The UK Compost Cheat Sheet

Which compost for which job

How much do you need?

Peat-free behaves differently

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