Fruit trees of various kinds grow in clay soil throughout the U.S. But not all produce the kinds of fruit you’ll find in your average fruit salad or fruit bowl. Many more much-loved fruit trees will grow in clay soil as long as it’s amended.
Some fruit trees do grow in clay soils, and many more grow in amended clay soils. Generally, fruit trees with a shallow root system, like stone fruit trees, do better in clay soil than others.
What is clay soil?
Clay soil has very small particles. When it gets wet, the soil feels sticky and you can form it into a ball, just like the clay we use for pottery. You will also find that it tends to stick to your tools and shoes, just like putty.
Heavy clay makes it particularly difficult for the roots of plants and trees to penetrate the soil and breathe. Tightly packed heavy clay soils also retain too much water and don’t allow the water from the surface to drain through.
You can’t see the individual clay particles, especially since they often accumulate in the lower subsoil layers of the soil. The topsoil is usually higher in organic matter, silt, and sand, and contains microorganisms.
This shows us that soil clays occur as a mixture of soils, meaning they aren’t pure clay systems. But, clay soil ranges from silty clay that you can dig into to hard, concrete-like soil you won’t be able to till.
The good news is that clay is usually full of minerals and nutrients, even though it lacks the air spaces that plant roots need to grow and thrive.
According to the Utah State University Forestry Extension, when surface soils are high in clay, it is often due to new construction work when the builders have removed the topsoil to build foundations.
They highly recommend that when this happens, the original topsoil is replaced. They also suggest that the compacted subsoil is broken up so that the plant roots can penetrate the soil.
Can you grow fruit trees in heavy clay soil?
Heavy clay soils present a major challenge, even for fruit trees that are known to grow well in clay. It is sometimes possible to amend heavy clay soil and make it suitable for growing fruit.
How do fruit trees grow in clay?
Most fruit trees grow best in clay soil when the soil is amended or improved. Lynne Marie Sullivan from Oregon State University’s Extension Service advises on the “proper” way to plant fruit trees in clay soil.
She bases her advice on what she calls “tillable” clay soil. This means that you’ll at least be able to dig holes in the clay when planting fruit trees.
How to plant a fruit tree in clay
Ms. Sullivan advises that the holes need to be 2-3 times as wide as the root ball and the sides must be rough (not smooth). It’s important that the hole is just deep enough to ensure the root ball sits about 3 inches higher in the hole than it did when it was growing in a pot or bag.
She warns that you mustn’t till the bottom of the hole because this can result in settling and sinking of the clay later on.
The next step is to fill your hole half full of water. Time is how long it takes for the water to drain out of the hole.
If it takes longer than 2 hours, you’ve got a problem and you need professional help. If it drains within 2 hours you can go ahead and plant your fruit tree.
Loosen the root ball so the roots are free and not winding around the center. Pop it into the hole and fill around it with the original soil mixed with a good handful (not more) of compost.
Tamp the soil around the base firmly so that the surface of the soil slopes away from the tree trunk. When the hole is full, cover the area around the root and trunk base with mulch to maintain soil moisture. Just don’t push it up against the base of the trunk.
Water slowly and deeply once or twice a week. If it rains, don’t water, but otherwise use a slow sprinkler or drip hose for a few hours each time.
Sullivan also believes in digging mature compost into the soil around the roots once or twice a year.
Mulching isn’t generally a good idea because it tends to exacerbate the problem by retaining too much moisture. This often leads to root rot.
What fruit trees thrive in clay soil?
There are a bunch of fruit trees that do grow well (or reasonably well) in clay soil. These include, in alphabetical order:
- Apricot and other stone fruit trees including plum trees
- Butternut, also known as the white walnut
- Falsa, which gets a sweet-sour fruit that is popular in India
- Hackberry that gets purple fruit that attracts birds
- Hawthorn, also known as thorn apple
- Sapodilla, which has incredibly sweet fruit
- Yellow mombin that has yellow, plum-like fruit
Many others will grow if you amend the clay soil, including fig, guava, loquat, mango, peach, and apple trees, as well as olive, cashew, avocado, and quite a lot of citrus trees.
But there is a caveat. Not all of these fruit trees will grow everywhere.
It’s not just the soil that is a factor. Climatic conditions are also hugely important.
The best idea is to ask around in your neighborhood to find out what other fruit tree growers have had success with. If they have experimented successfully, that’s a bonus for you!
If you don’t know people, try searching on Google. For example, if you live in Texas, search for something like “trees clay Texas”, “trees clay soil Texas”, or “make trees grow clay Texas”.
Alternatively, search for forums in the area where you live that discuss growing fruit trees.
Other soil types for growing fruit trees
All fruit trees will thrive in deep, well-drained soil. The ideal soil has a sandy, loamy texture and drains well. This is a far cry from clay!
The problem is that we can’t choose the soil we have available to grow in the ground. We have to make the best of what we have.
The answer is to amend the clay soil as best we can. So what can you do?
How to amend clay soils to grow your perfect fruit tree
Unfortunately, amending clay soils isn’t quick or easy. Clay soils don’t have adequate drainage and the soil is a lot harder, making it difficult for roots to grow.
There’s never enough organic material in clay soil and you won’t find worms to help improve the soil. There are also very few microorganisms in the soil to help make it healthier.
So what can you do?
For starters, a good rule of thumb when growing fruit trees in any type of clay soil is to add lighter material and soil emoluments to the hole. Here are some other ideas:
Adding compost to clay soil will always help, at least a bit. Mulching with worm castings is also a good idea.
It isn’t rocket science to realize that this will create a kind of sump and the roots of the tree will grow as if they are in a pot. You just need to be sure to dig over a much bigger area and to incorporate lots of organic matter, including compost.
Another proven amendment is gypsum. It helps to make the soil more saline and adds calcium.
Gypsum also changes the structure of the soil particles making them loosen. This helps both drainage and water retention.
Natural fertilizers are also a good option. What they do is to increase the useful microbes in the soil.
Beneficial fungi, which you can buy, is also an option. All you do is coat the root ball according to the instructions provided.
Mix in other soil types
Ultimately, you’ll be aiming to change the structure and character of your clay soil. So, when you are preparing the ground where you are going to plant fruit trees, dig in other types of soil.
If you can pick up decent stuff cheaply, do it. Otherwise bring in sand, peat moss, or anything else that might work.
Use a mulch
No matter what fruit tree you are growing, it’s also a good idea to mulch around the base of the tree to help stop the clay from splitting.
Choose the fruit tree you want carefully. Some will do better than others in clay soil.
But you will have gathered from these garden tips, that if you take the trouble to amend the soil, your fruit trees will benefit. Just because they will grow in clay soil, doesn’t mean you’re going to get a decent fruit harvest.
So make the extra effort and you are likely to be rewarded.