Wednesday, August 5, 2009

Garden Drainage: Importance Of Improving Soil Drainage

Ensuring good garden drainage is an important part of the gardening process. It is extremely important that all cultivated soil should be well drained. While some plants will need more watering than other which are more drought tolerant, regardless of this, they still require good soil drainage. Apart from water, the majority of plants require air around their roots as well therefore if the soil drainage is poor, so will the air supply, and the plants will suffer in the process.

Clay Drainage vs Sand Drainage

One of the most important questions about improving drainage is what sort of soil should be used in your garden. Is sand drainage better than clay drainage for improving drainage in your garden? Clay soil is probably what you are most likely to find in your garden. Heavy clay soil can be better for garden drainage due to the fact that it can retain nutrients and moisture, and the roots are steadier. The problem with sandy soil drainage however is, when free draining, water and nutrients are often leached out, the structure is not as steady as that of the heavy clay soil. As a result, clay drainage often proves to be a better choice for improving drainage. It is important to understand the nature of the soil you will be using in order to create a perfect garden.

Improving Drainage - Poor Heavy Clay Drainage

When improving drainage for your garden, these tips might come in handy.

  • Organic matter is usually the best answer to poor heavy clay drainage. The best material to use is rotted garden compost or farmyard manure. This should be done yearly by digging into the ground, the best time to do this is in autumn.
  • Bulky organic matter is good for improving drainage and open up heavy clay.
  • Peat and bark are the best as mulches and do a good job of improving the soil surface.
  • Always remember to use as much material as possible for better garden drainage.
  • If you have a large patch to cover, it is best that you concentrate on one area before moving on to the rest of the area if your material is limited. You will not get the same effect if you try and cover the entire area at once, you will see the benefits of this as time goes on.

Sandy Soil - Improving Poor Soil Drainage

When you are working with sandy soil steps need to be taken in order to increase the water holding capacity for better garden drainage. The reason for this is that sandy soil quickly loses any nutrients that they are given. Digging in plenty of compost is a very effective solution for improving drainage; however never dig deeper than the depth of one spade (25cm to 30 cm). Deep digging will open up the soil even more allowing water and nutrients to escape. The best time for digging is when you are ready for planting; always make sure that the soil is firm after digging or planting.

Poor Soil Drainage - Identify Badly Drained Soil

Very few plants can thrive with poor soil drainage. Certain plants such as vlei and marsh require the ground to be wet in order to thrive and the majority of garden plants cannot thrive if the ground is too wet and therefore improving drainage is vital. Badly drained soil? can be easily identified as it is:

  • infertile, which means it is lacking in important soil nutrients
  • lacks air
  • has reduced bacterial activity which will slow down decomposition and the release of nutrients into the soil.

Soil drainage is a very important aspect of gardening as it not only ensures proper growth of plants but will also prevent dehydration of plants and ensure that your plants receive the right amount of nutrients and water.


1. Prepare different soils - Garden Advice