Types of Soil in Ireland: The 11 Great Soil Groups

Drainage is the dividing line

Group Ireland’s soils by how well water moves through them and the picture simplifies immediately. The EPA’s 2024 State of the Environment report, drawing on the Teagasc Irish Soil Information System, splits the country three ways:

• Well and moderately drained soils (podzolics, brown earths, podzols and rendzinas): 55%
• Poorly drained mineral soils (gleys): 24.5%
• Organic soils (peats and lithosols): 18%

That is the whole story in three numbers. Just over half of Ireland drains reasonably. Almost a quarter does not drain at all well. Nearly a fifth is organic soil, mostly peat, which behaves differently from mineral soil in almost every respect.

The 11 Great Soil Groups

Teagasc classifies Irish soils into 11 Great Soil Groups, organised by the dominant process that formed them:

Grouped by	Great Soil Groups
Thick organic layers	Ombrotrophic Peat, Minerotrophic Peat
Shallow or very gravelly	Rendzina, Lithosol
Influenced by water	Alluvial, Groundwater Gley, Surface-water Gley
Iron and aluminium chemistry	Podzol, Brown Podzolic
Clay-enriched subsoil	Luvisols
Little profile development	Brown Earth

Beneath that grouping, the Irish Soil Information System national soil map works at a scale of 1:250,000 and maps 58 soil associations made up of 213 soil series, excluding areas of alluvium, peat, urban land, rock and marsh.

What each one means on the ground

Gleys, 24.5%. The most common soil in the country and the source of most complaints. Water sits in the profile, oxygen is excluded, and iron changes chemical state, which turns the subsoil grey or blue-grey, often with orange mottles where air does reach. Gleys are workable for a narrower window each year, poach badly under stock, and respond more to drainage than to feeding. If your ground is grey and sticky a spade’s depth down, this is what you have.

Luvisols, 19.3%. Clay has been washed down from the upper horizons and accumulated in the subsoil. The topsoil stays reasonably workable while the subsoil holds moisture and nutrients, which makes many luvisols good tillage ground.

Brown earths, 13.3%. Deep, free-draining, naturally fertile, with no strongly differentiated horizons because nothing extreme has happened to them. Ireland’s best all-round agricultural soils.

Brown podzolics, 11.5%. Free-draining, with an iron-stained subsoil that gives them their colour. Common on sloping ground.

Blanket peats, 10.5%. Thick organic soils formed under constant wetness across western and upland Ireland. Acidic, low in available nutrients, and a very large carbon store.

Podzols, 7%. Heavily leached and acidic, with the characteristic pale bleached layer under the surface. Typical of uplands, heath and conifer plantation.

Basin peats, 4.9%. The raised bogs of the midlands, formed in hollows left by glaciation.

Rendzines, 4%. Thin soils sitting directly on limestone. Free-draining to the point of drought, and naturally alkaline, which is unusual in Ireland.

Lithosols, 2.9%. Very shallow and stony, over hard rock. Limited agricultural use.

Why this matters if you are growing anything

Soil type sets the limits. It determines how much water your ground holds and how fast it loses it, how long the working window is after rain, how acidic the soil tends to be, and how much organic matter it can hold onto.

What it does not tell you is the state your particular field or garden is in right now. Two neighbouring fields on the same mapped soil association can differ by a full pH point and several nutrient indices depending on how they have been managed. The map tells you the constraints you have inherited. A soil test tells you what to do about them.

The practical order is: find out what soil you are on, accept what that fixes, then test to find what you can change.