Container Gardening Tips for UK Gardens

Choosing Containers

Material

Terracotta looks classic but is porous, meaning compost dries out fast. Glazed ceramic holds moisture better and looks smart but is heavy and fragile. Plastic is light, cheap and retains moisture well, but can look cheap. Wood looks natural but rots over time. Metal is modern but can overheat roots in sun. Composite stone is heavy, durable, and looks like real stone.

Size

Bigger is better. Small pots dry out fast, heat up in sun, freeze in winter, and restrict root growth. A 40cm diameter pot is the minimum for most shrubs and perennials. A 50cm pot is better. For trees and large shrubs, go 60cm or larger.

The cost of plants to fill a big pot is not much more than to fill a small one, but the effect is dramatically better and the maintenance is much lower.

Drainage

Every container must have drainage holes. Without them, water collects at the bottom and roots rot. If a pot has no holes, drill them. Cover the holes with crocks (broken terracotta) or mesh to stop compost washing out.

Raising pots off the ground

Stand pots on pot feet, bricks or tiles to lift them a few centimetres off the ground. This stops the drainage holes blocking and prevents the pot sitting in standing water in winter. It also protects wooden decks from staining.

Choosing Compost

Multipurpose compost

For annual displays and short term planting, peat free multipurpose compost is the standard choice. It is light, holds moisture, and has enough nutrients for the first 4 to 6 weeks. After that, plants need regular feeding.

John Innes compost

For permanent planting like shrubs, trees and perennials, loam based John Innes No 3 is the better choice. It is heavier, holds its structure for longer, and drains better than pure multipurpose. It is more expensive but worth it for plants that will be in the same pot for years.

Ericaceous compost

For acid loving plants like rhododendrons, camellias, blueberries and pieris, use ericaceous compost. These plants struggle in the alkaline soil of the Chilterns but thrive in pots of ericaceous compost, fed with an ericaceous plant food.

Mixing compost

For mixed summer displays, a mix of 2 parts multipurpose compost and 1 part John Innes No 3 gives a good balance of moisture retention and drainage. Add a handful of slow release fertiliser and some water retaining gel for extra reliability.

Peat free

Peat extraction destroys rare habitats, and the UK garden industry is phasing out peat. Peat free composts based on coir, wood fibre, green compost and bark are now widely available and perform well, though they can dry out more quickly than peat. See our guide to composting for making your own soil improver.

Planting a Container

Preparation

Cover the drainage holes with crocks. Add a layer of grit or coarse compost at the bottom for extra drainage. Fill with compost to about 5cm below the rim, leaving space for watering.

Planting

Water the plants in their original pots before planting. Remove from the pot, tease out the roots if they are congested, and plant at the same depth as they were in the original pot. Firm in gently and water thoroughly.

Spacing

For a summer display, plant closer than you would in the ground. The plants will fill out and the effect is fuller. For permanent planting, give plants room to grow.

Top dressing

After planting, add a layer of gravel or bark on top of the compost. This retains moisture, suppresses weeds, and looks tidy. Top up annually with fresh compost and slow release fertiliser.

Watering Containers

How often

In summer, containers need watering every day, sometimes twice a day in hot weather. In spring and autumn, every 2 to 3 days. In winter, only when the compost is dry.

The simple test is to push a finger into the top 2cm of compost. If it feels dry, water. If it feels moist, leave it. Overwatering kills as many plants as underwatering.

How much

Water until it runs out of the drainage holes. This ensures the whole root ball is wetted, not just the surface. A quick sprinkle does more harm than good because it encourages shallow roots.

When

Water in the early morning or evening, not in the heat of the day. Watering in full sun wastes water through evaporation and can scorch leaves if droplets act as lenses.

Self watering containers

Self watering pots have a reservoir in the base that the roots draw from. They need refilling every few days rather than daily, and are good for busy gardeners or for holiday periods. The RHS has a useful guide to watering containers for those who want detail.

Irrigation systems

For gardens with lots of containers, a drip irrigation system on a timer is worth the investment. Each pot gets a dripper that delivers water directly to the root zone. A basic system costs 100 to 200 pounds and saves hours of watering each week.

Feeding Containers

Liquid feed

Container plants need regular feeding because nutrients wash out of the compost with each watering. From April to September, feed once a week with a liquid feed like tomato feed, seaweed feed or a general purpose fertiliser. Tomato feed is high in potassium and is excellent for flowering plants.

Slow release fertiliser

Slow release granules mixed into the compost at planting time release nutrients over 6 months. They are convenient but only feed for one season, so annual top ups are needed.

Top dressing

Each spring, scrape off the top 5cm of compost from permanent containers and replace with fresh compost mixed with slow release fertiliser. This refreshes nutrients without repotting.

Winter Care for Containers

Pot protection

Frost can crack terracotta and ceramic pots and freeze the roots of plants. Wrap pots in bubble wrap or hessian in cold areas. Move tender plants in pots to a sheltered spot or unheated greenhouse.

Raising pots

Pots standing directly on the ground can freeze to the surface and block drainage. Stand on pot feet or bricks to keep drainage clear.

Watering in winter

Containers still need water in winter, but much less. Check weekly and water only if the compost is dry. Overwatering in cold weather rots roots.

Protecting tender plants

Tender plants in pots can be moved under cover for winter. Move pelargoniums, citrus, olives and fuchsias to a frost free greenhouse or conservatory. See our winter checklist for more on protecting tender plants.

Best Plants for Containers

Summer bedding

• Trailing: surfinia, lobelia, bacopa, calibrachoa
• Upright: pelargoniums, begonias, antirrhinum, salvia
• Foliage: coleus, ipomoea, helichrysum

Permanent shrubs

• Lavender: see our lavender profile
• Rosemary: see our rosemary profile
• Hydrangea: see our hydrangea profile
• Bay, box, dwarf conifers: classic evergreens

Shade containers

• Hostas: see our hosta profile
• Ferns: see our fern profile
• Hellebores: see our hellebore profile
• Begonias, fuchsias: for summer colour in shade

Winter containers

• Pansies and violas: the classic winter bedding plant
• Cyclamen: hardy cyclamen flower from autumn to spring
• Primulas and polyanthus: colour from late winter
• Winter flowering heathers: erica carnea and darleyensis
• Evergreen shrubs: skimmia, sarcococca, viburnum tinus

Vegetables in containers

• Tomatoes: tumbling varieties for hanging baskets
• Salad leaves, herbs, cut and come again: easy in troughs
• Potatoes: in special potato bags or large pots
• Strawberries: in strawberry planters or hanging baskets

Container Design Tips

The thriller, filler, spiller formula

For mixed containers, use one tall plant as the thriller (a phormium, a cordyline, or a tall dahlia), three or four bushy plants as fillers (pelargoniums, begonias, salvia), and two or three trailing plants as spillers (surfinia, lobelia, ivy). This gives height, body, and overflow.

Colour schemes

Stick to 2 or 3 colours for impact. Single colour schemes (all white, all blue) are sophisticated. Hot colour schemes (red, orange, yellow) are dramatic. Cool schemes (blue, purple, white) are calming.

Repetition

Repeat the same container and the same planting in several places for a unified look. Three identical pots of lavender along a path looks deliberate; three mismatched pots with random plants looks accidental.

Height variation

Vary the height of containers in a group. Three pots of different heights, with the tallest at the back, looks more interesting than three identical pots in a row.

Costs of Container Gardening

• 40cm terracotta pot: 30 to 80 pounds
• 50cm glazed pot: 60 to 150 pounds
• Multi purpose compost (60 litres): 8 to 15 pounds
• John Innes No 3 (25 litres): 8 to 12 pounds
• Summer bedding plants: 30 to 80 pounds to fill a 40cm pot
• Drip irrigation kit: 100 to 200 pounds for a small system

A fully planted 50cm container with quality plants and compost will cost 120 to 250 pounds to put together. See our soft landscaping service if you would like us to plant your containers.

Common Container Mistakes

Pots too small

Small pots dry out fast and restrict roots. Go bigger than you think you need.

Wrong compost

Multipurpose in a permanent planting degrades after a year and the plants suffer. Use John Innes No 3 for shrubs and trees.

Inconsistent watering

Letting the compost dry out completely between waterings stresses the plants and reduces flowering. Keep the compost consistently moist.

Not feeding

Container plants cannot send roots out for nutrients. They depend on you. Feed weekly from April to September.

No drainage

Pots without drainage holes drown the roots. If your pot has no holes, drill some.

Crowding too many plants

More is not better. Overcrowded plants compete for water and nutrients and never reach their full size. A 40cm pot needs 3 to 5 plants for a summer display, not 10. Trust the plant labels and give each plant room to fill its space.

If you want a fuller look quickly, choose plants that grow fast and trail, like surfinia, lobelia and bacopa. These will fill a pot in a few weeks without needing to be planted too densely at the start.

Final Thoughts

Container gardening is one of the most rewarding ways to garden. A few well chosen pots can transform a patio, a front door, or a balcony. The key is to invest in decent pots, the right compost, and consistent watering and feeding. Done well, containers outperform beds for colour and impact.

The secret is to start small, get a few pots working well, and expand as your confidence grows. A garden full of beautiful containers is built up over years, not in a single trip to the garden centre.

Container planting service

Frequently Asked Questions

How often should I water my containers?

Daily in summer, sometimes twice in hot weather. Every 2 to 3 days in spring and autumn. Weekly or less in winter. Push a finger into the compost; if it feels dry below the surface, water.

What is the best compost for containers?

For short term summer displays, peat free multipurpose compost. For permanent shrubs and trees, John Innes No 3. For acid loving plants, ericaceous compost. Mixing the two gives the best of both for mixed displays.

Can I reuse container compost?

Yes, but refresh it. Remove the top 10cm, add fresh compost and slow release fertiliser, and mix in some of the old compost. Do not reuse the same compost for more than 2 years because it becomes exhausted and can harbour disease.

How do I protect pots from frost?

Wrap pots in bubble wrap or hessian. Raise them on pot feet to keep drainage clear. Move tender plants under cover. In very cold areas, choose frost proof pots (fibreclay, composite, or frost resistant terracotta).

Further Reading

• Composting in the UK
• Winter garden tasks checklist
• Spring garden checklist
• Best plants for shade gardens

Sources and citations

This article draws on the following sources. Specific claims are cited inline where relevant.

1. CGM field records (2024-01. Site observations from gardens across Oxfordshire, Buckinghamshire, Berkshire and Bedfordshire.
2. Royal Horticultural Society (2024). RHS Gardening Advice and Plant Finder. Available at rhs.org.uk.
3. Met Office (2024). Regional climate averages, South East England. Available at metoffice.gov.uk.
4. British Geological Survey (2024). Soil parent material data for the Chilterns and Thames Valley. Available at bgs.ac.uk.