Content

• To step
• Part 1 of 2: Preparing to improve
• Part 2 of 2: Improving your soil
• Tips
• Necessities

Clay soil is a very heavy substance that can cause major drainage problems for your plants. This soil is common in many parts of the world and limits what families, gardeners and farmers can grow. But you can improve or supplement the soil to create a richer soil that is better suited for planting.

To step

Part 1 of 2: Preparing to improve

1. Before improving, you have to decide if you don't want to grow plants that can tolerate clay soil. This is probably the easiest option, and while you will be limited to a particular group of plants and trees, you can rest assured that what you "are going to" plant has a good chance of thriving. There are a large number of attractive plants and trees that tolerate clay soil.
   • Many plants have problems thriving in clay soil, no matter how effectively you improve the soil. Choosing plants that like very dry or very acidic soil can be an arduous, if not lost, battle.
2. Test the pH of your soil. The first step to improving your soil is determining the pH of your soil. There are several ways to do this, ranging from DIY strip tests to commercial test kits. If you're a serious grower, consider visiting a local farmers' union and getting your soil tested there.
   • Find the nearest farmers' union and bring a soil sample. The website tells you how best to do this. The farmers union performs the test for free. They test the acidity, soil structure and nutritional status of the soil. Your results will provide a detailed analysis of your soil composition, pH and what adjustments you should make to bring your soil into optimal growing condition.
   • pH is a scale of how acidic or alkaline a material is. The scale runs from 0 to 14, where 0 is very acidic, 7 is neutral and 14 is very basic.
3. Test the pH of your water. Improving your soil to make it more acidic, for example, will not have much of an effect if your water is very alkaline and you are going to use this water to water your plants. Don't get lazy - test the pH of your water as well as your soil. Most of the time, water is slightly alkaline, which may or may not be good depending on what you're trying to grow.
   • If your water is basic, it will be "hard" water. Groundwater generally becomes hard water, mainly because it does not corrode the pipes it is transported with. Acidic water is “soft”. Soft water is achieved by removing calcium and magnesium from the water.
   • If you want to be on the safe side, get pure filtered water. Pure, filtered water is as neutral as it gets. This way, using water will not affect the pH of your soil, although it can quickly become very expensive.
4. Try a percolation test. A percolation test will help you determine if and how well your soil is draining. Dig a hole that is 60 cm deep and 30 cm in diameter. Fill the hole with water and wait for it to sink completely. Now fill it a second time, keeping track of how long it takes to sink the second time:
   • If it takes less than 12 hours to settle, then you can safely plant anything that needs well-drained soil here.
   • If it takes between 12 and 24 hours for the hole to drain, you can safely grow plants that tolerate heavy clay soil.
   • If it takes longer than 24 hours for the hole to drain completely, then you can pretty much only plant trees that can withstand occasional flooding, such as the embalmed and red maple.
5. Dig the area you will be planting in. Spit to a depth of at least 15 cm and preferably 20 cm. Go a bit past the area to be planted. This allows you to provide the roots with extra growing space when they need it.
   • If you don't have any tillage tools, you can use a digging fork to loosen and ventilate the soil. The advantage of a digging fork is that you do not disturb the essential soil structure, thus helping the micro-organisms that live in the soil. The downside to just airing the soil instead of digging it is that heavy lumps of clay will still be there after loosening.

Part 2 of 2: Improving your soil

1. Do not work with clay soil when it is wet. Wait until dry weather is forecast before starting to improve the clay soil. Wet clay compacts much more easily, making adjustment much more difficult. You will need all the help you can get in improving clay, so make sure to remember this simple but effective trick.
2. Be prepared to improve a larger area of ​​land than you actually need. Measure the amount of space you will be adjusting. It is best to choose a large piece to improve. A small patch of improved soil can be a haven for your plants, but when their roots extend beyond the small patch and hit the clay, they will quickly retreat to the improved patch. This causes problems with the development of the root system.
3. Adjust the soil depending on the results of the test. Most clay soil is slightly alkaline, which means you probably want to “lower” the soil's pH. There are several ways to do this. The most common substances to add to clay soil are construction sand, gypsum, composted manure, compost or other coarse organic material.
   • Construction sand and plaster provide better water drainage and more air pockets; they help to make the pieces in the clay small.
   • Organic soil will help the plants get the right nutrients and also help make more humus (not to be confused with "hummus") with additional microbes that are the building blocks for good soil. In addition, they will help lower the pH of the soil, acidify it.
   • Try to focus on an equal mix of coarse sand (construction sand) and coarse organic material. Because you are going to spread this mix over a larger area, you have to think in bulk quantities and cubic meters instead of bags and square meters. One cubic meter of material can effectively cover the top 7.5 cm of 10 m2.
4. Start by spreading 0.75 m³ of organic material over each piece measuring 25 x 25 cm. Start with organic matter first. After it has been mixed with the clay soil, the material will start to break down and become effectively invisible. Don't worry - it's still there and doing the job.
5. Then spread 0.75 m3 of construction sand over the same area of ​​25 by 25 cm. Mix it thoroughly with the organic matter and clay using a soil preparation machine. If you don't have one, you can rent one cheaply from a nearby hardware store.
   • If good quality construction sand is not readily available, you can also use green sand or plaster as an alternative. This is more expensive, but works in the same way to loosen the clay parts, allowing more water and air to be added.
   • Gypsum has been found to be particularly effective in areas where the soil has a high salt concentration.
6. Continue to monitor the soil's pH. Pay close attention to whether the pH changes. Most plants cannot tolerate drastic changes in pH or soil conditions, so you should be reasonably sure that the pH of your soil is done drastically changing before planting.
7. If necessary, acidify the soil further. Clay is usually very alkaline by nature. For this reason, you may want to change the soil's pH to make it more acidic. There are several ways you can do this:
   • By adding a fertilizer based on ammonium.
   • By adding elemental sulfur or iron sulfate.
   • By adding cottonseed meal, peat moss or other compost.
8. Avoid automatic water systems for your plants. Because clay soil is so good at retaining moisture, automatic water systems can drown your plants if you don't pay attention to it. Discard the sprinklers, save some money, and look at the plants themselves to determine how much water they need.

Tips

• If you don't have a farmer's union nearby, call gardening associations, garden centers, or hardware stores and find out where you can get a soil test done. Wageningen UR can also mean something for you.
• Sometimes it is easier to choose plants that grow well in clay soil. Clay is so dense that it can be difficult to dig in and improve.

Necessities

• A spit
• Organic material or compost
• Horticultural sulfur (if the pH is 7+) or quicklime (if the pH is 6-)
• Construction sand, blood meal or green sand