Puddles in Your Lawn? 

Is your soil soggy? Do puddles form on your lawn? Few plants like their roots wet for long periods; most garden plants prefer well-draining soils. This article walks you through what might be causing lawn puddles and things you can do to help resolve the issue.

What is Well-Draining Soil?

Well-draining soil is a soil where water can infiltrate at a 'medium' rate; somewhere between running straight off the top and draining as though someone pulled a plug. The best soil is about half air space and half solid mineral, with 2-5% organic matter. Under ideal growing conditions, about half of the air space will be filled with water. If the soil is too wet, plant roots fail to get the oxygen they need. If the soil has too much air space and drains too quickly, plant roots dry out too easily.

How to Test Your Soil Drainage

Dig a hole 30-40 cm across and 30-40 cm deep. Fill the hole with water. If water completely drains from the hole in less than 10 minutes you have fast drainage. If the water takes more than an hour to drain, you have poorly drained soil. If the water takes between 10 minutes and 1 hour to drain it is well-draining.

What is Your Soil’s Texture

Also, assess your soil’s texture, be it clay, sand, or something in between.

All soils are largely made up of tiny mineral particles. The size of mineral most abundant in your soil determines whether you have sand, loam, or clay. This mineral composition of the soil is called the soil's "texture."

Sand particles are small but compared to other soil particles they are largest. The other two main categories of soil particles are silt, which is smaller than sand, and clay, which is still smaller.

• Sand – Sandy soils are fast-draining; water and nutrients move through sand soils fast meaning both need more frequent replenishing. A handful of sandy soil won't clump or hold a shape when you press it.
• Loam – Loam soils a well-draining; these soils have a beneficial mix of all the mineral particle sizes.
• Clay – Clay soils are poorly-draining; microscopic clay particles pack together tightly. Water and nutrients move into and through clay soils slowly. Clay soils are heavy, and you can easily form a ball or ribbon with a clump of moist clay soil in your hand.

Most soils are mixtures of all three particle sizes but in varying proportions. A predominance of sand particles makes a lighter, more open soil with good drainage and aeration; lots of channels for air and water circulation. Minute clay particles pack together tightly making a clay soil heavier, denser, and with less favourable air and water circulation.

How to Improve Soil Drainage of Poorly Draining Soils

Depending on the situation in your garden here are some suggestions to turn poorly-drained soil into well-drained soil:

• Build raised beds – Raised beds have plenty of ways for water to drain away, down and out to the sides. You can also more easily control what sort the soil texture is by adding sand, loam, clay and organic matter in good proportions.
• Add organic matter - Adding organic matter to existing soil in the form of well-rotted manure, compost, or peat moss helps change poorly-draining soil into well-draining soil. Interestingly it also helps fast-draining soil hold on to water longer.
• Apply LawnPro D-Thatch - LawnPro D-Thatch helps break down thick layers of thatch (dead grass material) on to of the soil and below the grass blades that might be preventing drainage and reducing oxygen penetration to the grass roots.
• Put in drains - A more labour-intensive solution to altering soils with poor drainage is to install underground drainage.
• Fork wet areas of lawn - In lawns poor-drainage may cause puddles to form in wet weather. If puddles are there for more than a day they can ‘drown’ lawn grasses. Try forking the area as the poor-drainage may be due to soil compaction on the surface. Over the whole area at locations, 20-30 cm apart push the fork at least 20 cm deep and gently ease the handle back slowly to open the soil allowing water to pass through and air to penetrate the soil.
  An alternative is to use a lawn plug remover (hollow tine aerator) which takes small plugs of soil out leaving holes to allow drainage of water and penetration of air. The plugs can be left on the lawn to re-incorporate naturally.
• Add gypsum - Adding gypsum to clay soils can help improve drainage by stopping the small clay particles sticking together so tightly, but adding organic material may be a better option in most cases other than lawns.
• Create a water feature – Creating a water feature, such as a pond, where excess water from surrounding areas can drain to, will add an attractive focus to your garden, allow a variety of plants to grow and will help drainage of surrounding soils.
• Make the best of it - If you can’t improve the drainage of your soil because of its location, e.g. it is low lying and near a water source such as pond or river, turn the conditions to your advantage and plant damp loving plants such as Carex grasses, native flax, Toetoe, Parataniwha, Marble leaf, and many others. Talk to your local garden centre or nursery for advice.