What Does Well Drained Soil Mean?
How To Get A Well-Drained Garden Soil
How Do You Know If Your Soil Is Good Or Poor Drainage?
The first thing you need to do is determine if your garden soil is good or poor drainage. The best way to test the drainage of your garden soil is with a simple gravity test. Use a small shovel and scoop up some of the soil. Let it sit for at least 15 minutes before measuring its weight. If the weight remains constant, then your garden soil is not draining very well.
If you are having problems with your drainage, there are several things you can try to improve it:
1) Add organic matter such as compost or manure to increase water retention in your garden soil.
2) Increase the amount of mulch around your plants to retain moisture.
3) Make sure that your irrigation system is working properly.
Watering too much can cause the soil to become compacted and therefore less likely to drain properly. (See our article on watering.)
4) Use a drip irrigation system instead of a sprinkler system.
This will help to prevent the soil from becoming compacted.
What Is Well Drained Soil?
Well drained soil is a mixture of sand, silt, clay and organic matter. The different components allow the soil to drain properly but still hold enough moisture to support plant life. Gardeners often see well drained soil as one of the most important factors when choosing a location for building a home garden or landscaping an area. City planners also consider the quality of garden soil when deciding where to build houses and businesses.
Good drainage is especially important in areas that are prone to flooding or extended periods of rain. Every homeowner should learn how to test the garden soil for proper drainage. If your garden soil does not have good drainage, there are several things you can do to make it better including:
1) Adding sand or stone around plants or trees will help improve drainage.
2) Adding organic matter such as compost or leaf mold will add air pockets that will help water flow through more easily.
3) Raising the beds in your garden helps to prevent water from pooling around the plants.
4) Make sure that your gutters and downspouts are working correctly to prevent rainwater from flooding your garden.
What Does Well Drained Soil Look Like?
A well drained soil will look like normal garden soil after you have wet it. It should hold the impression of your finger for a few seconds before it starts to collapse back into place. If you dig down deep enough you should not see water at the bottom of the hole.
Some communities have naturally well drained soil but others, especially those in flat areas prone to flooding, may need help. Cinder blocks or large rocks can be added around plants that are prone to flooding. Raised beds can also be built to improve drainage in areas with poor soil.
What Does Poorly Drained Soil Look Like?
Poorly drained soil will not hold a finger impression and collapses back into place immediately. It may feel wet even if you have watered it recently. Digging down a foot or two you may see water pooling at the bottom of the hole.
How Can I Improve Poorly Drained Soil?
There are several ways to improve poorly drained soil. If your garden is prone to flooding in the spring, you should try to prevent excess rainwater from building up around your plants:
1) Rake away leaves and other organic matter that can block downspouts and gutters.
2) Build walls or plant windbreaks to block high winds that can prevent rainwater from draining away.
3) Remove tall weeds and grasses near your garden because they can prevent water from draining away
4) Create shallow trenches from the bottom of your garden area to a spot where the water can drain naturally. Be careful not to dig too deep or you could end up with waterlogged soil.
5) Install a French or Dutch drain under your garden to redirect excess water.
This can be a fairly expensive solution and you will need to contact a professional if you decide to go this route.
6) Building raised beds can also help improve drainage and make it easier to work in your garden.
Raised beds drain better because they are not in direct contact with the soil below.
7) Adding sand and stone around plants or trees will help improve drainage.
How Can I Test The Drainage In My Garden Soil?
Moisten your soil to the depth of a shovel and make a hole about a foot across and as deep as the shovel blade. If the hole begins to collapse on itself the soil does not drain well. Addition of perlite, vermiculite or gravel can improve drainage. If you can keep your fist in the hole for five seconds or more, your soil has good drainage.
Do soil tests include testing for drainage?
Drainage is rarely included in soil tests, but there are labs that will test for perlite and other drainage enhancing additives if you need them. To ship perlite can be expensive so check with local labs in your area to see if they offer this service. You can also find out who does independent testing for garden centers in your area. They may also test for drainage additives.
Does Soil Drainage Affect Plant Survival?
Yes, lack of nutrients and water are the number one killers of houseplants. Many people kill their plants by over or under watering. If you don’t have well drained soil and enough drainage for the plant you are growing, roots will sit in waterlogged soil and eventually rot.
Poorly drained soil can also cause root rot because drainage is poor. The plant may also suffer from nutrient deficiencies because the water draining from heavily watered soil washes nutrients away. If you have poor drainage you should add nutrients with each watering to replace what was washed away.
So how can I tell if I’m over or under watering plants?
One of the easiest ways to test soil is to perform the finger test. Insert your forefinger into the soil up to the first knuckle.
Can you keep it there for five seconds before it starts to collapse? Try it with a few fingers, can you keep them all in there for five seconds?
If so the soil is well drained enough. If you can’t keep them in for five seconds or more you need to improve drainage or increase the amount of watering.
If you can keep your fingers in there for five seconds but the soil is still collapsing as you take your fingers out then you need to improve drainage and water less frequently.
With time, experience and a bit of common sense you will get better at judging how much water your plants need.
The Four Categories Of Soil Types
1) Well Drained Soil – If you can keep your fist in the soil for at least five seconds, then it drains well.
It allows excess water to drain through the soil and doesn’t allow puddles to form. This type of soil has good air circulation which prevents most diseases. This type of soil is good for succulents, cacti and other plants that need well drained soil.
2) Some Clay – If you can only keep your forefinger in the soil up to the first joint then it has some clay in it.
This type of soil drains a bit slower than the well drained soil but will still drain properly if you don’t overwater. This type of soil has good air circulation which helps prevent root rot and other diseases. This type of soil is good for all types of plants that don’t have special drainage requirements.
3) Peaty – This soil has a lot of peat or sphagnum moss in it.
It drains very slowly and needs to be water thoroughly every few days. It also needs to be packed very tightly when preparing the soil.
4) Potting Soil – Also contains bark and compost which hold moisture well.
It should only be used for plants that like continually moist soil. This soil has poor drainage and will not drain properly, this can lead to root rot.
Sources & references used in this article:
Uptake of a hydrologic tracer (bromide) by ryegrass from well and poorly‐drained soils by RR Schnabel, WL Stout… – Journal of Environmental …, 1995 – Wiley Online Library
… to Waterlogging and Differing Sensitivity to Divalent Iron and Manganese in Clones of Dactylis glomerata L. derived from Well-drained and Poorly-drained Soils by JR Etherington, OM Thomas – Annals of botany, 1986 – academic.oup.com
Tree species composition and rain forest-environment relationships in the middle Caquetá area, Colombia, NW Amazonia by JE Duivenvoorden – Vegetatio, 1995 – Springer
Vegetation and soils in an eastern Indiana woods by A Smith, B Doll, S Gengel – 1998 – US Department of Education
Getting to know a catena: A field exercise for introductory soil science by EW Beals, JB Cope – Ecology, 1964 – JSTOR
Moisture content of extensive green roof substrate and growth response of 15 temperate plant species during dry down by PL Gile – 1911 – Porto Rico Agricultural Experiment …
Enhancing agriculture’s potential to sequester carbon: a framework to estimate incentive levels for reduced tillage by RR Weil – Journal of Natural Resources and Life Sciences …, 2003 – Wiley Online Library