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How to plant a pot: compost, rim gap, then watering

Updated: 22 October 2026

The box is on the kitchen floor, and the brand name will not water the plant. How to plant a pot is a sequence: confirm a hole, choose a peat-free mix, leave a rim, then water until surplus leaves. The Royal Horticultural Society writes that sequence for UK containers. The [flower pots comparison](/hub/plant-accessories/flower-pots) is where the twelve listings sit. This page does not rank them. Peter F. used the public RHS notes and these listings. We did not pot these ASINs in a trial. A qualifying purchase can earn us a commission at no extra cost to you.

The box is on the kitchen floor, and the brand name will not water the plant. How to plant a pot is a sequence: confirm a hole, choose a peat-free mix, leave a rim, then water until surplus leaves.

Our top picks

LE TAUCI LE TAUCI (ceramic pair)

Best overall

LE TAUCI LE TAUCI (ceramic pair)
8.2/10about £28.99
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SG Traders SG Traders (30 cm pair)

Rank 2

SG Traders SG Traders (30 cm pair)
8.8/10about £19.99
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CSYY CSYY (6 sizes)

Best value

CSYY CSYY (6 sizes)
8.7/10about £10.99
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On this page
  1. 1.Stop if there is no hole
  2. 2.Which peat-free mix
  3. 3.The planting sequence
  4. 4.Watering and the saucer

Stop if there is no hole

Hold the pot up to the window before you open the compost. If you cannot see a hole, stop. The RHS treats drainage holes as essential in a planting pot. A saucer is not that hole. B2C’s 30 cm pot ships a saucer and states no pre-drilled holes. Straame’s 50 L barrel arrives watertight. If you wanted a planting pot, you now have a cache-pot job or a drilling job, on plant pot with no drainage holes. LE TAUCI has a hole plus a plug. If the plug is in, the hole is closed until you take it out. Do not jump from a 12 cm nursery pot into a 30 cm patio pot the same afternoon. A UK guide treats 3–5 cm wider than the rootball as a rule of thumb.

Which peat-free mix

Use peat-free compost. Multi-purpose peat-free is the short-term bag for seasonal colour and houseplants you will pot on. A soil-based peat-free mix, the John Innes style still sold in UK sheds, holds structure for shrubs in a 30 cm pot. Ericaceous peat-free is for acid-lovers such as blueberry, camellia and some heathers. BBC Gardening makes the same split. Do not invent a feed calendar from this page. Follow the bag. Peat-free mix can look dry on top while it is still moist underneath, so push a finger deeper than the crust. A 15 cm indoor pot does not need a shrub mix. Once a 50 L Straame tub is drilled, wet compost is the balcony weight, not the empty gramme on the listing.
LE TAUCI LE TAUCI (ceramic pair)

Testsieger

LE TAUCI LE TAUCI (ceramic pair)
8.2/10about £28.99
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The planting sequence

Water the plant in its nursery pot first. Cover only a large hole. The RHS uses crocks when the hole is over about 2.5 cm; small mesh holes do not need a shard layer. Add peat-free mix so the rootball sits about 5 cm below the rim. That gap is how you water without washing compost over the side. If roots circle the old pot, tease the outer ones. Set the plant in the centre, fill around it, and firm with your fingers. Water until surplus shows at the holes. On LE TAUCI, take the plug out unless you are using a closed cache for a short time, and put a plate under it. Do not leave a new 30 cm pot in a deep patio tray through a wet week. Diameter, if you have not bought yet, is on the flower pots buying guide.

Watering and the saucer

Water in the morning or the evening in summer, and water until surplus leaves. Empty indoor saucers a few hours later. Take outdoor saucers off for winter. A January tray is a frost bucket around the roots. Plastic holds moisture longer than terracotta. Check with a finger, not a calendar. Rainwater is the RHS preference where possible. Tap water is what most UK kitchens have. The larger fault is a full winter saucer. Do not leave CSYY’s trays brim-full because the title said self-watering. You do not need a professional to pot a peace lily into a 15 cm pot. You do need one before you load a balcony with several wet 30–50 L tubs if you do not know the rating.

Common questions

What compost should I use?
Peat-free. Multi-purpose for short-term colour and houseplants you will pot on. A soil-based peat-free mix for longer-term shrubs in a large pot. Ericaceous peat-free for acid-lovers. The RHS and BBC Gardening both use that split. Do not put a blueberry into ordinary multi-purpose and hope.
Do I need crocks in a plastic pot with small holes?
Not if the holes are small. The RHS uses crocks when a hole is over about 2.5 cm. Mesh holes in a 15 cm indoor set do not need a crock layer. A shard layer in a shallow pot only steals room from the compost.
How full should I fill the pot?
Stop about 5 cm below the rim, which is the RHS watering gap. The top of the rootball should sit at that level, not proud of the rim and not buried under a mound. Without the gap you cannot water through without washing mix over the side.
How often should I water a container in summer?
There is no honest calendar that fits every pot. The RHS says morning or evening, and to water until surplus leaves. Peat-free mix can look dry on top while it is still moist below, so use a finger deeper than the crust. Plastic indoor pots in this set hold water longer than terracotta.
When do I take the saucer off?
Empty indoor saucers a few hours after a summer watering. Remove outdoor saucers for winter so rain and frost do not sit around the base. A tray is a drip catch, not a pond. A holed pot left in a full winter tray behaves like a sealed pot.
Can I jump from a 12 cm nursery pot to a 30 cm pot?
You can, and you will have a ring of wet compost around a small rootball. A UK guide rule of thumb is 3–5 cm wider, one size at a time. Use the 15–21 cm indoor pots in this folder first.
Rainwater or tap?
Rainwater where possible, in the RHS wording. Tap water is still what most UK kitchens have. The larger fault is a full winter saucer, not the tap. Use the tap if that is what you have, and empty the dish afterwards.

Related pages

Indoor or outdoor flower pots

Flower pots

Best plant pots UK: one listing for each job in this set

Plant pots with drainage: what to check before you buy

Plant pot no drainage holes: cache pot, rain, or drill

Sources

Public UK sources used for this comparison. Shelf prices, stars and review counts are the amazon.co.uk figures captured for these twelve listings. Last checked 19 October 2026.

  1. RHS: Growing plants in containers (retrieved 19 October 2026)
  2. RHS: How to plant up a container (retrieved 19 October 2026)
  3. RHS: How to water containers (retrieved 19 October 2026)
  4. RHS: Roof gardens and balconies (retrieved 19 October 2026)
  5. RHS: Peat-free tips for gardeners (retrieved 19 October 2026)
  6. BBC Gardening: Plant up a container (retrieved 19 October 2026)
  7. Consumer Rights Act 2015, section 22 (retrieved 19 October 2026)
  8. GOV.UK: General Product Safety Regulations 2005 (retrieved 19 October 2026)