Independent comparisons. We may earn from shop links. More info

Compost for hanging baskets

Updated: October 2026

A summer basket on a sunny wall can be dry by the evening, and the bag you carry to the hook has to be light enough to lift once the basket is wet. Compost for hanging baskets, for a display that lasts one year, is peat-free multi-purpose compost, not a heavier John Innes mix and not a crystal basket compost unless the bag says so. None of the seven amazon.co.uk bags in the [Flowers compost comparison](/hub/fertiliser-soil-and-bark-mulch/flowers-compost) claims a crystal pack. We used Royal Horticultural Society basket guidance and the amazon.co.uk listings. We did not weigh a finished basket.

A summer basket on a sunny wall can be dry by the evening, and the bag you carry to the hook has to be light enough to lift once the basket is wet.

Our top picks

GROWMOOR Growmoor multi-purpose compost 50 L

Best overall

GROWMOOR Growmoor multi-purpose compost 50 L
8.0/10about £9.25
View offer
Miracle-Gro Miracle-Gro peat-free compost 20 L

Rank 2

Miracle-Gro Miracle-Gro peat-free compost 20 L
8.6/10about £7.95
View offer
DIVCHI DIVCHI potting compost 10 L

Alternative

DIVCHI DIVCHI potting compost 10 L
6.4/10about £7.70
View offer
On this page
  1. 1.The compost a one-year basket needs
  2. 2.Litres in the basket, kilos in the bag
  3. 3.Water every hot day
  4. 4.Feed after the bag runs out
  5. 5.Which basket job you have

The compost a one-year basket needs

The RHS says peat-free multi-purpose is enough for a hanging display that lasts one year. Plant towards the end of May or early June, after the frost risk. Shop baskets often advertise a six-month feed and water-retaining granules. None of these seven listings is that product. Only Miracle-Gro’s 20 litre listing prints peat-free and a feed of up to 3 months. Shrubs and ericaceous plants belong on the compost for flowers buying guide.

Litres in the basket, kilos in the bag

Miracle-Gro 20 litres is listed at 6.15 kg, the lightest loose bag here. Growmoor 50 litres is 12 kg and suits more baskets when the label does not have to say peat-free. Growmoor 60 litres is 14 kg, Munnie is 14.9 kg, and the CB Fuels listing is 22 kg. DIVCHI is 680 g for a 10 litre claim, a compressed block with no peat-free line. The RHS does not give a kilogram figure for a finished basket, so this page will not invent one.
GROWMOOR Growmoor multi-purpose compost 50 L

Testsieger

GROWMOOR Growmoor multi-purpose compost 50 L
8.0/10about £9.25
View offer

Water every hot day

Baskets dry faster than other containers. In hot weather, summer annuals sometimes need water every day. After the first thorough soak, a light basket is often a dry one. The finger test is on how to use compost for flowers.

Feed after the bag runs out

Only Miracle-Gro states up to 3 months. Follow that line, then use a high-potassium liquid feed. The other bags state no window. None of these bags is a six-month crystal compost. A shrub that stays up all year needs a loam-based mix, and the extra weight is the point of that compost.

Which basket job you have

If the display lasts one year, use peat-free multi-purpose, and in this set only the 20 litre listing prints those words. If you are filling several baskets and peat-free is not required, the 12 kg sack is the larger fill. If the plant stays all year, leave this set.

Common questions

Is ordinary peat-free multi-purpose compost enough for a summer basket?
For a display that only has to last one year, the RHS says yes. Specialist bags with crystals and a six-month feed are a different product, and none of these seven listings claims that pack. You still water daily in hot weather and you feed when the bag’s window ends. A shrub you will keep, or an acid-loving plant, wants loam-based or ericaceous compost instead. Those mixes add weight a one-year basket does not need.
How many litres does a 35 cm basket hold?
There is no single figure. Wickes says approximately 8 litres for a 35 cm classic basket. A Smart Garden 35 cm basket says approximately 7.5 litres. Another retail line says 10 litres. Read the claim on the basket you are planting. A calculator that turns a half-sphere into about 7 litres is a model, not the liner in your hand.
Will a 20 litre bag do more than one basket?
It can, if your baskets sit in that 7.5 to 10 litre band. Two baskets at about 8 litres each use most of a 20 litre bag. Miracle-Gro’s 20 litre listing is the peat-free bag in this set, at 6.15 kg. If your liner is larger than the maker claim, measure the first fill before you assume a second basket is covered. Do not treat 8 litres as true of every 35 cm frame.
Why does a 50 litre sack make a basket harder?
The compost in the liner may only be 8 litres. The sack you carry to the hook is the problem. Growmoor 50 litres is listed at 12 kg, and the 60 litre, Munnie and CB Fuels rows are 14 kg, 14.9 kg and 22 kg. A wet planted basket is heavier again. The 50 litre bag is useful when you are filling several baskets and you do not need a peat-free line. It is a poor buy for one basket up a flight of stairs.
How often should I water in a hot UK spell?
Check every day, and water when the compost is dry a couple of centimetres down. In hot sun, summer annuals sometimes need water daily. Morning is the better time. A weekly routine under-waters a basket on a south-facing wall and over-waters one in a cool, shady porch. If the basket wilts, catch the runoff in a bucket and pour it back rather than soaking the patio.
Does a light basket mean it is dry?
After the basket has been watered through once, a sudden lightness usually means it has dried. Before that first soak, a fluffy dry mix can feel light while it still needs a slow wetting, not a daily splash. Lift it at the same time each morning so you learn the weight. Water the compost with a fine rose, and stop before you wash the liner out.
What if the basket is for a shrub that stays up all year?
Change the compost, not the watering slogan. The RHS points long-term basket plantings at a loam-based peat-free John Innes, and it warns that the loam adds weight. None of these seven bags is John Innes. Acid-loving plants want ericaceous compost. A one-year peat-free multi-purpose bag is the wrong medium for a shrub you expect to see next summer.

Related pages

Best flowers compost

Flowers compost

Compost for flowers buying guide: type, litres, feed

How to use compost for flowers once the bag arrives

Peat-free compost for flowers: England ban explained

Sources

Public UK sources from the research digest, used for this page in October 2026. Prices, stars and review counts are from the seven amazon.co.uk listings read on 21 October 2026. There is no laboratory test. Peat-free means the listing prints peat-free. An announced retail end date is not an Act. The Growmoor 50 litre and 60 litre review texts in this set are one shared sample.

  1. Defra, sale of horticultural peat to be banned (retrieved 21 October 2026)
  2. Written question 99957, 18 December 2025 (retrieved 21 October 2026)
  3. Deposited letter, 29 January 2026 (retrieved 21 October 2026)
  4. RHS, hanging baskets (retrieved 21 October 2026)
  5. RHS, growing plants in containers (retrieved 21 October 2026)
  6. RHS, peat-free tips (retrieved 21 October 2026)
  7. RHS, John Innes compost (retrieved 21 October 2026)
  8. RHS, minimising health risks in the garden (retrieved 21 October 2026)