Soil needs to drain. When soil doesn’t drain water well, there can be big problems in your garden, including a negative impact on the health of your plants!
Poor soil drainage is a really common problem because most lawns and gardens do not start out with great soil. Whether you want to plant a garden, a lawn, or a tree, trust me when I say that you want your soil to be well-draining, loose, fluffy, and not clumpy.
If you know you have compacted soil or clay soil, the good news is that it is fairly simple to fix with organic soil amendments. So, let’s talk about how to improve soil drainage.
Laying The Groundwork
Soil is the foundation of a healthy, productive garden. If you don’t have good soil quality, your plants are going to suffer.
The following list of blog posts provide straightforward, practical tips to help you build fertile, living soil that will support stronger plants and better harvests!
Negative Effects of Poorly Draining Soil
Poorly draining soil might not be visible at first glance, but it will significantly impact the health and aesthetics of your lawn or garden.
The first effect you may notice is runoff. Runoff is when precipitation or irrigation water cannot penetrate the soil. When the water cannot be absorbed, it flows over the surface, running off and taking precious topsoil and nutrients with it.
The next problem that can occur is root suffocation. Roots need oxygen just like you and I do. Soil that is tightly compacted or waterlogged doesn’t have adequate air in the soil to support life (remember bacteria, fungi, and beneficial insects also need air), and will choke the roots of garden plants, halting nutrient absorption and eventually killing the plant.
Lastly, poorly draining soil can become baked, killing beneficial microbes and organisms in the soil. This happens when soil dries out and hardens in the sun. All exposed soil is susceptible to soil solarization, but compacted soil can heat up extremely hot since there is very little moisture or air in the soil to act as an insulator to keep the soil at appropriate temperatures.
How to Improve Soil Drainage
These 5 simple soil amendments can dramatically improve soil drainage:
Perlite - This is an expanded volcanic glass that you will often find as an ingredient in high-quality seed starting mix.
Sand - When used correctly, sand can create porosity in your soil.
Compost - Organic matter (compost) that is found in soil acts as a sponge, holding onto water and keeping the soil conditions hospitable for life.
Vermiculite - Like perlite, vermiculite is another volcanic rock that is critical in your seed starting mixes for preventing compaction and retaining moisture.
Gypsum - Calcium sulfate (gypsum) is a great natural soil amendment for improving soil drainage and clay soil.
Perlite
Perlite is a volcanic rock that is puffed like popcorn to be very lightweight. It helps to loosen soil, prevents compaction, allows better drainage, and helps with general soil fertility. It also has the added benefit of being able to hold onto water, which can help prevent soil from baking and cracking.
There are different grades of perlite. I prefer using medium to fine perlite. Extra-fine will work, too, but you will need to add more of it.
Sand
Sand is one of the cheapest things you can add to your garden soil that will help to break up the soil, especially if it is mixed with compost before amending. The small particle size of the sand will get in between soil clods and break them up, increase drainage, and help to aerate the soil for good root development.
Compost
The problem with many hard, heavy, and compacted soils is that there is a lack of organic matter. Compost is an obvious, but often overlooked, amendment to fix poorly draining soil.
It is one of the most effective things for improving soil structure, allowing drainage to flow, and preventing compaction. Plus, it replenishes nutrients in the soil and feeds your plants. Every gardener will benefit from knowing what compost is and how to make compost for your garden!
Vermiculite
Vermiculite is very porous, allowing it to absorb water and nutrients so they don’t wash away. This glassy, flat-looking material is extremely absorbent, and when used with any combination of compost, perlite, or all three, it will break up even the hardest of soil and turn it into a usable soil that can grow plants better than you could have imagined!
Gypsum
Gypsum is great because, if you have heavier clay soil, it actually gets in between the clay particles and breaks them up. It actually loosens the chemical bond of the clay that keeps it nice and tight, which will fluff your soil. This does take time, but it should allow you to have a garden the first year.
For heavy clay soil, I would recommend a hybrid approach. Apply some gypsum to help loosen up the clay, but also incorporate high-quality compost into the native soil at the same time to make it very homogeneous.
Mulching to Fix Poorly Draining Soil
While technically not an amendment that you mix into your soil, mulching can do miracles for your soil! This method does take time to work, but it can be very effective if done right.
Mulch holds onto water very well, breaks down and decomposes slowly, protects the soil from baking, and allows worms and other garden insects to feed on the slowly breaking down organic material. This softens soil, and can create perfectly loose soil in as little time as two to four years.
How to Use Amendments to Make Well Draining Soil
To improve soil drainage, choose the amendments you will use based on your soil conditions, and work them into the top 6 inches of soil until the topsoil is loose and friable (has a crumbly texture that breaks apart easily).
Heavy clay soil and compacted soil are two of the most common causes of poor drainage. According to a study done by the University of Minnesota, using a shallow till method with hard pan underneath can be a great benefit to those who want to grow crops but have compacted or clay soil. As long as you have about 5 to 6 inches of loose soil above the hard pan soil, you can grow a lawn or garden.
To achieve 5 to 6 inches of friable topsoil, you may need to bring in compost and do some shallow tilling. I recommend spreading gypsum and high-quality compost onto your soil and using a hard rake as a rotatiller to essentially break up and loosen the top 5 to 6 inches of soil, like I demonstrated in the video at the beginning of this blog post.
Pro-Tip: It’s true that plants grown in these conditions will have a shallower and less sturdy root system, but its a great place to start. Each year that you amend your soil, it should get better. I don’t want you to give up on precious years of having a garden because you struggle with compacted or poorly draining soil!
