Ericaceous Compost

Acid-loving plants need suitable soil conditions to take up mineral nutrients such as iron and manganese. In lime-rich, high-pH soil, these nutrients can become less available. This can cause yellowing leaves (chlorosis), weak growth and poor performance.

Ericaceous compost provides an acidic root environment for suitable plants. Iron is a mineral nutrient, and an appropriate pH helps the plant use the nutrients available.

Use a soil-testing kit before deciding how to plant. On alkaline or chalky ground, containers filled with ericaceous potting compost are generally easier to manage than a small pocket of acidic compost in the existing soil. Changing the pH of a whole garden can be difficult to sustain.

Learn more from the RHS guide to chalky soils and nutrient availability, or read about ericaceous beds. Choose plants and compost together, and follow the individual product’s care guidance.

Use ericaceous compost for acid-loving plants when the growing medium needs to be acidic. This is particularly useful in containers if your garden soil is neutral, alkaline or chalky.

Test the soil with a pH kit rather than relying only on what grows in neighbouring gardens. A pH above 7 is alkaline, but some acid-loving plants need a much lower pH, so check the requirements of the plant you want to grow.

Blueberries generally prefer a pH of 4.5–5.5. If your soil is unsuitable, grow them in a container of peat-free ericaceous compost. Rhododendrons, azaleas and camellias also need the right conditions; they are not a reason to assume alkaline soil will be suitable.

It can be difficult to maintain a lower pH in very alkaline ground. A pot or a suitably designed raised bed gives you more control over the growing medium.

Ericaceous compost is available from garden centres and compost suppliers. Choose a product specifically labelled ericaceous; ordinary multi-purpose or John Innes compost is not automatically suitable for acid-loving plants.

Our peat-free ericaceous compost comes in 40-litre bags, with packs from a single bag to 50 bags. Use the product page to choose the quantity and check current availability. For pallet orders, plan for kerbside delivery to a suitable flat, hardstanding area rather than delivery into the garden. Read our delivery and access guidance before ordering.

Growing acid-loving shrubs in pots

Compact rhododendrons, including Rhododendron yakushimanum hybrids, and dwarf azaleas can be good choices for containers. Camellias can also be grown in pots, but choose a variety and container suited to its eventual size.

Use a pot with drainage holes and move up gradually as the roots fill it, rather than putting a small rootball into a much larger volume of wet compost. Check the plant regularly for watering and repotting needs.

Compost structure and nutrient reserves change over time. Repot when needed, refresh the growing medium and feed with a fertiliser suitable for ericaceous plants, following the product instructions. Spring is a useful time to assess plants as growth resumes.

Choose ericaceous compost for plants that need acidic conditions, rather than treating it as a general-purpose compost. These RHS guides explain the needs of individual plants.

• Azaleas and rhododendrons: colourful flowering shrubs, many of which suit containers. Most need acidic conditions. RHS rhododendron and azalea guide.
• Blueberries: fruit for desserts, baking or eating fresh. They prefer acidic soil, ideally pH 4.5–5.5. Read our guide to growing blueberries or the RHS blueberry guide.
• Camellias: flowering evergreen shrubs that can be grown in suitable containers. RHS camellia guide.
• Acid-loving heathers: Calluna and Daboecia need acidic conditions, but not all heathers do; some Erica varieties tolerate alkaline soil. RHS heather guide.
• Enkianthus: a shrub valued for its small flowers and autumn colour. Enkianthus campanulatus grows in acid or neutral soil, so specialist ericaceous compost is not always essential. RHS Enkianthus profile.
• Kalmias: evergreen shrubs with distinctive patterned flowers. Check the species and growing conditions; Kalmia latifolia is commonly grown in acidic soil. RHS Kalmia latifolia profile.
• Pieris: flowering evergreen shrubs, including ‘Forest Flame’, with colourful young foliage. RHS Pieris ‘Forest Flame’ profile.

What about other fruit, vegetables and herbs?

Raspberries, parsley, tomatoes and rhubarb are useful garden crops, but they should not be grouped with blueberries as plants that automatically require specialist ericaceous compost.

• Raspberries: prefer fertile, well-drained, slightly acidic soil. See the RHS raspberry guide for ground and container growing.
• Parsley: can be grown in peat-free multi-purpose compost in containers. RHS parsley guide.
• Tomatoes: need a suitable growing compost or fertile, moisture-retentive, well-drained soil. RHS tomato guide.
• Rhubarb: prefers fertile, moisture-retentive soil without waterlogging; a large container needs a suitable soil-based compost. RHS rhubarb guide.