Over the years, I’ve helped plant and grow dozens of fruit trees for both myself as well as my parents, but one persistent challenge keeps coming up—clay soil. After doing some research on planting fruit trees in clay soil, I found mostly conflicting information. So, I wanted to really dive in deep and set the record straight. Here’s what I found.
Fruit trees can grow in clay soil as long as it drains well. However, it’s generally best to avoid planting in clay soil due to its poor drainage and alkalinity. Instead, plant fruit trees on 1 to 2-foot mounds of garden soil on top of the ground and add 1-foot of mulch. Expand the mound as the tree grows.
So, while it is possible to grow fruit trees successfully in clay soil, which fruit trees grow better, and what’s the best way to plant them? Let’s take a closer look.
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Which Fruit Trees Can Grow in Clay Soil?
|Fruit Trees That Can Grow in Clay Soil*||Fruit Trees That Can’t Grow in Clay Soil|
If you see your fruit tree on this list, don’t worry! It’s not difficult to amend your clay soil and grow fruit trees.
Fruit trees such as apple, cherry, and peach can grow well in some clay soils, while citrus, avocado, and mango will have a hard time growing. Generally, most fruit trees dislike heavy clay soil and prefer loose, well-draining soil with a slightly acidic pH. For best results, plant the fruit tree on a mound.
As long as your climate supports it, there are almost always simple solutions to adjust your soil to your tree’s preference.
We’ll get into how to plant fruit trees and amend their clay soil, but first, why is clay so bad in the first place?
Why Clay Soil Is Bad for Fruit Trees
Clay soil is bad for fruit trees because its smaller particles create poor drainage and its alkalinity blocks nutrient uptake. While some fruit trees can survive in clay soil, it often results in little to no growth and fruiting. Generally, avoid planting in clay soil and instead plant in non-clay areas or on mounds.
The two biggest problems with planting in clay soil are poor drainage and alkalinity, which blocks nutrients. Fruit trees are the most vulnerable to these issues when they’re under 3-5 years old. After this, they usually have established a mature root, canopy, and immune system.
Let’s take a deeper look at why drainage and alkalinity are problems for most fruit trees.
In clay soil, the smaller and tightly-packed particles are sticky when wet and make for a poor draining medium. Think of that ceramic class you took when you were little and how the wet clay stuck to your hands. While clay soil isn’t usually that extreme, it can have a similar effect.
On the other hand, sand has larger particles and is gritty, offering plenty of space for drainage. However, sometimes this drainage is too extreme and results in the nutrients leaching through the soil along with the water. This is one good benefit of clay soil—the poor drainage not only holds water, but nutrients.
So, too much clay will hold excess water and nutrients, while too little won’t hold enough water and nutrients. So, what’s the right mix?
The best soil for trees is made from a mix of sand, clay, and silt. While you can amend your clay soil with sand, organic materials such as leaves, bark, and compost will do just as well, if not better.
Another issue with clay is that it can easily become sunbaked, causing cracking and erosion. This is a huge problem and many gardeners lose much of their topsoil this way.
Amending clay soil to promote more drainage and nutrients is one to resolve these many issues, but before we look at that, do we even need to amend it in the first place?
Why You Shouldn’t Dig in Clay Soil
I strongly recommend not digging down into the clay at all. Rather, always build up so that when the water drains through the mound, and subsequent topsoil, it hits the clay and gets diverted away like a slow, seeping underground river, rather than gather in a hole. No matter how large it is or how much good quality growing medium is thrown in, a hole in clay is not a good idea.Mark, from Self Sufficient Me
Many gardeners, including me and my parents, have made the mistake of digging a hole to plant fruit trees in clay soil (as shown in the first photo). This is a problem because while the fresh soil filled into the hole may be well-draining, the clay underneath it essentially creates a “bucket” in the ground, holding large volumes of water.
This water-holding nature of clay is made even worse if it’s pottery-grade, as its particles will be packed even tighter.
The biggest problem with digging a hole is that since 90% of a fruit tree’s roots are found in the top 2-feet of soil, they have little chance of growing past the “bucket” in the clay soil. Dwarf fruit trees are even less likely to grow past this due to their smaller root systems.
Over time, the water that’s held in the hole will rot the roots, leading to issues such as wilting, browning, and dropping leaves. After 1 week to 12 months (depending on the severity), it can kill the tree.
This condition caused by waterlogged soil is commonly called root rot, or Phytophthora Root and Crown Rot. This disease was previously thought to be a fungus but was recently found to be a separate species called oomycete, or water mold.
My potted Kaffir lime tree had root rot recently and I could tell because its soil was sopping wet and smelled like a swamp. After repotting the tree in fresh soil, the roots dried out enough to made a quick recovery.
However, root rot is the most harmful when the taproot is affected.
The taproot is the main root of the plant and unlike most of the other roots, the taproot’s job is to dig straight down into the soil—similar to how we dig for a well. Since the taproot of fruit trees commonly reaches 3-feet deep, it can be more affected by poor drainage than the other, shallower roots.
If the taproot dies, the tree will have suffered a crippling blow and will have a difficult time surviving. This can commonly result in the tree either having stunted growth or dying completely.
So, by digging a hole in clay soil and planting your fruit tree, you just might be giving it a death sentence.
Again, I made this mistake many times and only recently have learned otherwise, so don’t be too hard on yourself if you’ve done something similar. While some of our fruit trees died in the clay soil, others have grown quite well. Clay soil won’t kill a tree every time, but it’s definitely better to avoid it if possible.
Aside from poor drainage, the other problem with clay soil is its alkalinity.
Generally, clay soil is too alkaline for most fruit trees as they prefer a slightly acidic soil pH of 6.0-7.0. If the soil’s pH is either too acidic or alkaline, the fruit tree won’t be able to properly absorb nutrients from the soil. This can cause issues such as leaves and fruit yellowing, browning, and dropping.
Typically, heavy clay soils have a pH of 8.5 and above. This is primarily due to naturally occurring minerals such as sodium carbonate and sodium bicarbonate (baking soda), but other man-made causes can also contribute to it.
When the alkaline soil binds nutrients, fruit trees typically won’t have enough nutrients to thrive. This commonly leads to stunted growth. Over several years, the tree’s health can decline and result in death.
So, if you have a fruit tree that’s planted in clay soil and it’s had little to no growth, this is likely why. The nutrient-locking ability of alkaline soil can also cause several conditions such as leaves and fruit wilting, yellowing, browning, and dropping.
While you can amend clay soil, it’s not always necessary.
If you haven’t planted your fruit tree yet, planting on a mound will remove the need to amend the soil.
Giving your fruit tree a proper soil pH will help ensure it’ll grow well over the years and provide you with the maximum amount of fruit.
How To Tell If You Have Heavy Clay Soil
Grab a handful of your soil and give it a light squeeze. If it falls apart when you open your hand, the soil is mostly sandy. If the soil stays clumped but then falls apart when you prod it, it’s balanced and in good condition. If the soil stays clumped, even after prodding it, you have clay soil.
There are 4 main ways to test your soil for a high clay content. They are:
- Ball test
- Cake test
- Drainage test
- Lab test
We’ve already covered the ball test above, but what about the cake test?
Cake Test: Simply, wet the soil and press it flat with both hands. If it sticks to either hand, you have clay soil. If you hold your palm out and the soil is still sticking to it, you have heavy clay soil.
If you still aren’t sure if you have clay soil, you can always test its drainage.
Drainage Test: Dig a 1-foot by 1-foot hole and fill it with water. If the water doesn’t drain within 1 hour, the soil likely has a high amount of clay and needs to be amended for better drainage.
Finally, you can always send a sample of your soil to a lab to be analyzed for pH and nutrient levels. An easy way to do this is by sending it to your local cooperative extension.
How To Plant Fruit Trees in Clay Soil
As mentioned above, avoid digging into clay soil to plant if possible. We’ll cover fruit trees that are already planted in clay soil next, but for now, follow these three steps when first planting your fruit tree.
1. Build a Mound
On top of the clay ground, build a mound of well-draining and rich soil 1-2 feet high and as wide as the tree’s drip line or canopy.
Since 90% of the fruit tree’s roots are found in the first 2 feet of soil, it’s best to aim for 2 feet of soil. This way the roots don’t have to deal with the clay and can instead thrive in the quality soil.
2. Plant the Tree
Make a small hole in the middle of the mound as wide as the fruit tree and plant the tree in it. Check that the bottom of the tree’s root ball is at least 1-2 feet from the clay ground.
If you’d like some extra tips on planting (and how to best avoid transplant shock), these are the steps I use when I’m planting fruit trees:
- Have the mound prepared
- Remove as much of the tree’s current topsoil as possible, without damaging the shallow roots
- Grab the base of the tree’s trunk and wiggle lightly
- Using your other hand, scoop up and support the rootball
- Lightly place the tree in the center of the mound and fill it in
- Make sure the soil is at the same level on the trunk as before
After you do these planting steps, there are just two more you need to do to help the tree thrive.
3. Add Mulch
To mulch your fruit trees, add mulch 1-foot high and as wide as the drip line of your tree. Place the mulch in a donut shape around the tree and keep it at least 3-inches from the trunk to avoid mold and disease from spreading. Good mulches for fruit trees include leaves, bark, straw, pine needles, and grass clippings.
Mulching is one of the most beneficial practices you can do for your fruit trees.
Fruit trees generally evolved in forests where the leaves and branches from other trees would line the forest floor. This created a thick layer of mulch and provided nutrients, insulation, protection, and well-draining soil.
Today, fruit trees that are conventionally grown are typically planted by themselves and left to the elements to survive. They have no other trees to lean on for shade, mulch, and support. Additionally, roots are amazing at holding water in the soil, so trees planted alone don’t have this extra water from the other tree’s roots and can quickly dry out.
While these are all benefits to planting trees near each other, there are some practices we can use to help the trees survive (for both individual trees as well as orchards). And one of the best ways is to use mulch.
Not only will the mulch help the soil retain water, but it protects the soil from the elements such as sun, wind, and rain. This greatly decreases the soil’s erosion and helps the beneficial soil life thrive.
After mulching your fruit trees, water the fruit tree generously by spraying the mulch. Avoid spraying the tree’s leaves as this can spread some diseases such as fire blight.
Alternatively, you can plant your fruit trees in 3-foot tall raised beds.
Not only will raised beds provide better draining soil than the clay ground, but the higher elevation will let gravity assist in pulling the water out from the bottom of the soil.
If you’d like to see some of the most popular raised beds for fruit trees, check out this page on Amazon.
How To Amend Clay Soil for Already Planted Fruit Trees
If your fruit tree is already planted in clay soil, and it’s growing decently, it’s best not to move or replant it. This can cause more damage through transplant shock and lead to issues such as wilting, browning, and dropping leaves. Instead, apply 2 inches of each sand, compost, and mulch to the top of its soil.
Over time, these materials will work their way into the soil, breaking up the larger clumps of clay. The compost and mulch will also provide quality nutrients (potentially removing the need for fertilizers) and feed beneficial soil life such as worms and mycorrhizal fungi.
However, if you test your soil’s drainage and find your fruit tree’s roots are getting waterlogged, transplanting or repotting the tree onto a mound or raised bed is probably a good idea.
Here are all of the soil amendments that can help fix clay soil:
- Pine bark
- Pine sawdust
- Coffee grounds
- Peat moss
The best time to amend soil is before the fruit trees are planted. However, if they’re already planted, and the trees are doing fairly well, adding the 2 inches of each sand, compost, and mulch will help amend it over time.
More Tips To Grow Fruit Trees in Clay Soil
- The best way to water fruit trees is to only water when the first 2-4 inches of soil are dry. A good way to check for this is to push a finger into the soil, up to the second knuckle. If the soil is dry, water it. If the soil is sopping wet 1 or more hours after watering it, it likely needs to be amended for better drainage.
- Enlarge the fruit tree’s mound as it grows. Try to match the mound with the tree’s drip line.
- Avoid repotting or relocating the fruit tree unless the drainage is so poor that it’s creating root rot. Transplant shock can create more stress and damage to the tree and should be done as a last resort.
- Avoid tilling the clay soil as it exposes the soil life to the elements and leads to erosion. Instead, build on top of the clay soil.
- Look for labels when buying fruit trees such as “does not like wet feet”. However, most fruit trees don’t do well with wet feet, so it’s a best practice to avoid it if possible.
- Observe your fruit tree’s native conditions. Fruit trees generally evolved in forests with rich soil and lots of mulch. Additionally, most tropical fruit trees such as citrus, avocado, and mango are used to soils with more sand, while temperate fruit trees such as apple, cherry, and peach prefer more loamy soil.
- Plant companion plants around your fruit trees to help amend the soil, boost pollination, and deter pests. You can also use ecological succession like planting hardier plants in the clay ground first such as pigeon peas, ice cream bean, and other cover crops. These plants will help fix the clay soil before you plant your fruit trees.
- Avoid using gravel as rocky soil can make it more difficult to dig and for the fruit tree to spread its roots.
- Be patient—it could take 1-2 years or more before you see the soil life change from the amendments.
- Plant dwarf fruit trees in pots if you don’t want to deal with amending your clay soil.
- Run livestock through your orchard to help amend the clay soil and keep pests at bay.
If you haven’t planted your fruit tree yet, then consider building a mound of soil and mulch for it on top of the clay soil. This practice will provide the best drainage, pH, nutrients, and protection for your fruit tree.
On the other hand, if your fruit tree is already planted and is doing well, don’t change anything. Still add compost and mulch to the top of the soil, but you shouldn’t need to amend it completely.
However, if you notice your planted fruit tree isn’t growing well or is dying, it might be time to amend the soil.
Keep in mind that you can either amend the tree’s topsoil or relocate the tree to a mound. However, moving the tree will introduce the chance of transplant shock. You’ll have to weigh the pros and cons and see if it’s necessary to take this risk and move the tree to a better soil type.
If you’d like more information to find out why your fruit tree might be declining in health, check out my recent article:
To see why digging is one of the worst things you can do for fruit trees in clay soil, check out this great video by Self Sufficient Me. Mark gives amazing details about how his avocado trees died in clay soil and why planting in mounds was such a win for him.