How to improve soil drainage
Water is a chemical substance no living organism can live without and plants are not an exception to the rule. But too much water can often cause more damage than improvement. Therefore, knowing how much moisture your garden can accommodate to provide benefits, is crucial.
Different soil types react differently to water absorbance. Clay retains moisture very well often leading to waterlogging. Waterlogging occurs when air pockets in the soil are temporarily filled with water eliminating the oxygen and preventing important microorganisms, responsible for soil breakdown and nutrient release, to thrive. Root rot also appears.
Sandy soil drains very well, and this often leads to drought, especially during the hot summer months. Furthermore, lack of water causes the soil to overheat, creating the hostile environment for the plant roots. Nutrition is usually washed away together with water.
Loam soil, if well maintained, is not troublesome and action should only be taken in areas with heavy rainfall.
How to improve soil drainage:
- French wells
- Regular maintenance
- Soil alterations
- Redesign the area
French wells are very beneficial especially in waterlogged lawns, next to retaining walls or edge of a border. They are relatively easy to install but are not always labour and cost effective.
How to install a French drain?
- The depth greatly depends on the amount of rainfall you are getting. Mostly they are up to 1m (3 feet) in depth and 30cm (1 foot) in width.
- Start by digging a trench of measurements described above in the area most affected or at the bottom of the slope if applicable. The trench should be dug all the way to the nearest drainage.
- Place landscape fabric at the bottom and sides of the trench. This will prevent the silt in soil from entering and possibly blocking the drainpipe.
- Place approximately 4 inches of washed stone on top of landscape fabric and lay down the perforated pipe. Connect to the nearest drainage point.
- Fill the rest of the trench with washed stone to approximately 4 to 6 inches below the surface level. Washed stone is free of any sand grain and other debris to prevent any blockage.
- You can cover the stone stones with remaining fabric and restore the topsoil. See the diagram below.
Soakaways work similarly to French drains, only this time you don’t need to lay down perforated pipe and connect it to the drainage.
Dig a trench in the area most suffering from waterlogging. Similarly, to French drains, place down the landscape fabric. Landscape fabric is fully permeable, and the excess water will freely drain. Fill the trench with stone, washed or crashed, again, 4 to 6 inches below the surface. It is not necessary to use washed stone as there is no danger of pipe getting blocked.
Opposed to French wells, the excess water won’t be redirected, but instead will be absorbed by the surrounded soil.
There are many reasons for the topsoil to compress down, such as heavy foot trafficking, use of garden machinery, or a simple exposure to winter weathering conditions. When this happens, the air pockets in soil will be reduced or even eliminated, therefore the water can’t find any depository areas easily.
Regular soil maintenance helps to prevent this. During the spring soil maintenance, the topsoil air pockets are fully restored helping the water to penetrate to the surface easily. For best results, we recommend maintaining topsoil at least twice a year, after and before the winter.
Clay soil in the garden is the most common and obvious reason for waterlogging. Clay is composed from very small particles and they only allow for microscopic air pockets unable to accommodate any excess water and become a solid structure. By altering the soil texture, the drainage improvement will come naturally.
To improve the texture of clay in the border, apply course material together with well-rotted manure or garden compost (your own) and work in the soil by using a fork, cultivator, or rotavator if the border is free from any flora. The course material such as sand or horticultural grit will create additional air pockets, needed to accommodate the excess water.
Manure contains a large number of micro bacteria needed to break the clayey soil down. After several months the topsoil texture will drastically improve, and the waterlogging problem will disappear on its own.
This process can be reversed if you are dealing with a sandy soil. As opposed to clay, sand is composed from large particles creating large air pockets and allowing the water to penetrate and drain freely. Downside of sandy soil is inability to retain any moisture causing the soil to overheat. This is a hostile environment for any plant inhabitants and their root system.
To improve water retention, apply a good quality of topsoil and cay together with well-rotted manure. The manure, in this case, will provide the missing nutrition as sand hardly retains any. Topsoil and clay bring in smaller particles narrowing down the air pockets, contributing to overall moisture retention. Work well after application.
Aerating or aeration generally applies to lawn maintenance. With the use of garden machinery, the lawn tends to compact down. Allowing the air into the soil allows the micro bacteria and earthworm to thrive and approves water penetration.
You can improve the soil aeration by lawn scarification followed by spiking. Scarifier removes the unnecessary moss and dead grass, creating an extra space for the water to enter the soil. The spike aerator, making the holes in the soil, will direct water into the soil where it will be absorbed.
For best results, run both equipment one way followed by cross way. We recommend doing this at least two times a year, in the spring and in the autumn.
Redesign the troubled area
At times you might be dealing with conditions that are extremely hard to improve. In this case, the most effective and natural way is to adapt to the given environment.
Consider creating a pond surrounded by a “boggy” area. Make sure to select only appropriate plant material such as calla lilies, some irises or march marigold. This will prevent the costly replacement in the future.
For easier access and walk around your garden, apply a thicker layer of cobbles, pebbles or a stone chipping also for decorative purposes.
Although the importance of water cannot be stressed enough, it’s intake should be regulated to benefit any living organisms. Use these few ideas and principles to improve water intake and outgoingness. Your plants and your garden will thank you in the most kind way.