Why Spruce Trees Love Acidic Soil (How To Test Yours!)
Throughout the changing seasons, the spruce tree still displays an unchanged hue of green. Because of this, spruce trees make the perfect ornamental tree, Christmas tree, and backdrop to the Rocky Mountains no matter the season. Even when the last of the leaves finally drop, the needles of the evergreen spruce don’t miss a beat.
But did you know that spruce trees naturally root in regions of higher elevations and colder climates?
They have the unique ability to adapt to different soil pH levels but prefer acidic soil. Spruce trees love acidic soil because it creates an environment that allows better nutrient absorption and overall tree growth.
The pH of your soil can greatly affect the development of your spruce tree from the ground up. If your spruce is struggling, consider testing your soil to uncover the root of the problem.
Do Spruce Trees Like Acidic Soil?
Yes, spruce trees like acidic soil. They actually prefer it.
Spruce trees are native to colder regions, which is why you see forests of them in the coldest and most northern climates of the United States.
In these colder, elevated regions of heavy rainfall, certain nutrients in the soil begin to dissolve creating conditions of acidic soil beneath them.
If you are considering planting a spruce tree, make sure to head on over to our article about the best spruce trees to plant! That way if you currently have acidic soil, or if you have a different kind, you can find the best spruce to match your environment!
Spruce Trees Adapt To The Soil
Spruce trees have learned to adapt to these ever-changing soil conditions and can thrive in different pH values ranging anywhere from alkaline to acidic. You’ll most likely find them growing on mountain slopes, along rivers, and sometimes even in your neighbor’s yard!
A study conducted by the Scandinavian Journal Of Forest Research discovered that when compared to ash, beech, elm, hornbeam, and oak trees, spruce trees generated the most acidic soil.
If you find that your soil doesn’t meet their standards, keep reading to learn ways to make your soil more acidic.
Why Do Spruce Trees Love Acidic Soil?
Soil pH is measured on a scale of 0 to 14 where any number under 7 means acidic and anything above means alkaline. For spruce trees, a soil pH of anywhere between 5.0 and 8.0 is optimal for growth.
With the ability to slide between slightly alkaline and strongly acidic, spruce trees are extremely adaptable.
The pH of the soil determines the availability of essential nutrients taken up by each tree which can greatly influence the overall growth of any tree.
Acidic soil generates the optimal environment for your spruce tree to tower over all of the others while containing all the nutrients it needs to thrive.
Acidic Soil Helps Spruce Trees Absorb Nutrients
The soil beneath your spree tree becomes acidic as a result of the environment around it.
Heavy rainfall can drain your soil of minerals that are more abundant in alkaline soils, such as calcium and magnesium.
Spruce trees love acidic soil because of the nutrients available to reach their roots. Acidity allows for more nutrient absorption into the trees. Hence why you see a lot of spruce trees on mountains and in snowy areas!
Acidic Soil Has More Moisture
Acidic soils also hold moisture better. Because spruce trees have shallow roots, dry and humid climates can easily damage them. Be sure you’re staying on top of watering your spruce tree!
Moisture and nutrient uptake are the two most important factors in spruce growth, which is why spruce trees love acidic soil.
In fact, the waxy coating on the needles of your spruce conserves water, so when the soil below is frozen, they are still getting the water they need during those cold, mountain winters!
As you can tell, spruce trees need a lot of water to survive as well – which is why acidic soil is so perfect for them! Head on over to our article about watering spruce trees, to find out the best ways to do it, and how much water they will need!
Acidic Soil Speeds Up the Spruce Tree Growth Timeline
Research from Michigan State University indicates that conifers grow best in acidic soil, and an increase in soil pH may dramatically slow spruce tree growth.
A conifer is any tree that bears cones instead of flowers and forms needle-like foliage instead of leaves. Spruce trees are conifers and are also evergreens.
With the proper acidic soil environment, the spruce tree can focus on sunlight intake to shoot up towards the sky as the roots that are spread down below worry less about fighting for essential nutrients.
Spruce trees also need sunlight to grow, and may not do as well without ample enough sun. For more info on why spruce trees need sunlight, head on over to our article to learn more!
How To Make Soil Around Your Spruce Trees More Acidic
There are very few trees and plants that can tolerate acidic soil. Luckily, your spruce tree can tolerate acidic and alkaline soil.
However, if you want your spruce tree to look and grow its best, you’ll want to create an acidic environment around it, which starts in the soil.
To make your soil acidic, you can add compost, coffee grounds, and fertilizers to the soil beneath your spruce.
Spruce needles themselves are also acidic! As they drop from the tree, they will decompose and add hints of acidity to the soil.
Monitoring the health of your spruce is important, especially if it pertains to soil health. For instance, soil issues such as poor nutrients or improper pH can cause a slew of issues such as tree reddening and needle drop.
Apply Compost To Increase Spruce Tree Acidity
If you’re looking to organically increase the acidity of your soil, add compost.
Well-decomposed compost will slowly increase the pH of your soil and the overall growth of your spruce tree.
Compost is composed of decomposed organic matter, such as leaves, twigs, kitchen scraps, and other organic materials.
You can create your own compost by saving leftover scraps, fruit and vegetable peelings, and the mountains of leaves that are starting to pile up around your home.
Compost May Take A Long Time To Work
Although adding compost to your soil improves the overall soil structure, it is not the quickest fix to your soil acidity.
Compost only increases soil acidity over time, so throughout the growing season, you will see a gradual increase in acidity and the health of your spruce.
This is still an amazing option to increase your soil acidity and overall growth and can be used in combination with other options!
Spread Coffee Grounds Around Your Spruce Trees To Help Acidity
It takes time to craft a compost pile and allow the organic material to decompose properly before use. If you’re looking for something to increase the acidity of your soil this morning, go grab those coffee grounds from your freshly brewed pot of coffee!
Spreading coffee grounds throughout the soil under your spruce tree can increase soil acidity.
You can simply sprinkle the coffee grounds on the soil, add them to your compost pile for an extra acidic boost, or cultivate the coffee grounds into the soil beneath your spruce to help the acidity.
Coffee grounds also contain up to 2% nitrogen, which is beneficial to the overall growth of your spruce! They do not, however, contain any phosphorus or potassium.
Try Using Fertilizer To Make Your Soil More Acidic
If you’re searching for a quick, full-proof way to increase the acidity of your soil, consider purchasing an acidifying fertilizer.
Many premade fertilizers contain macronutrients, micronutrients, minerals, and beneficial bacteria that can help acidify your soil and promote growth.
Espoma Organic Evergreen-Tone is an all-natural fertilizer proven to increase acidity and promote the overall growth of your spruce tree. This fertilizer contains the minerals and bacteria necessary to keep your spruce thriving!
Evergreen-Tone Fertilizer is formulated specifically for your at-home evergreen trees, including your spruce tree. It is ready to use, and recommended that you feed your tree once in early spring and once in the late fall.
Here’s a full list of our top recommended spruce tree fertilizers if you’d like to take a look!
How To Test Your Own Soil At Home
If you’re unsure if the soil is the reason your spruce is struggling, it is best to test your soil before trying to amend it.
Of course, it is always best to test your soil before ever planting your spruce tree!
There are many ways to test your soil at home. You can even test your soil without leaving your home by using items found in your cabinets!
Buy A Basic Soil Testing Kit To Test Your Soil At Home
The simplest way to test your soil is with an at-home soil testing kit.
In many states, you can simply contact or visit your local conservation department to secure a soil testing kit! If you opt for this route, you’ll likely have to mail or drop off the soil sample and wait for the results.
For a quick at-home test, you can purchase a simple soil testing kit online. In a matter of minutes, you can have the pH of your soil in your hands! No mailing or waiting is required.
Here Are Some Great PH Testers!
Luster Leaf is a brand that has created two different kits to quickly test your soil however you prefer.
This Luster Leaf BioLogic Soil pH Tester is a simple rapid test that displays the exact pH of your soil. This kit even contains ten different tests!
They also have a Digital Soil pH Meter that you can stick in the soil and receive the results within minutes! These options require minimal preparation, test quickly, and come at an affordable price.
The optimal pH for a spruce tree should be between 5.0 and 8.0, and each of these tests will provide readings for you to determine if your spruce’s soil falls between these numbers.
Add Baking Soda To Soil As An At-Home Acidity Test
You can test your soil at home with baking soda.
This soil test does not provide exact readings, but it will give you an idea about the type of soil that is underneath your spruce.
How To Test With Baking Soda
- To prepare for this soil test, you’ll need at least 2 tablespoons of moistened soil from your spruce tree and ½ cup of baking soda.
- Once you have gathered these materials, place your soil in a bowl and moisten it with distilled water. Tap water may provide skewed results, so be sure to apply distilled water to your soil.
- After you’ve moistened your soil, add ½ cup of baking soda. If the mixture fizzes in any way, you have acidic soil.
Of course, you won’t know just how acidic your soil is. If the acidity falls below 5.0, it is possible that your spruce will start showing signs of disease or deficiencies.
Add Vinegar To Your Soil To Alter Acidity
This test is just as simple as the one above but includes vinegar instead of baking soda. Surely you have one of the two!
You can quickly test your soil at home with vinegar! Here are the steps:
- To prepare this soil test, you’ll need at least 2 tablespoons of soil and ½ cup of vinegar.
- Once you’ve gathered soil from your spruce, add it to a bowl. The soil does not have to be moistened for this test.
- Lastly, you’ll add ½ cup of vinegar to your bowl of soil. In this case, if the mixture fizzes, you have alkaline soil.
For most plants and trees, this is good news! For your spruce tree, this could be the reason your spruce is struggling.
BUT – spruce trees can still grow healthy in alkaline soil! They just don’t love it. If your spruce doesn’t seem to be thriving, consider diving into the options above to make your soil more acidic!
Wrapping Up!
To sum up, spruce trees love acidic soil. Not only are their needles themselves acidic in composition, but the climate in which spruce trees thrive is a breeding ground for acidic soil.
Most importantly, acidic soil allows your spruce tree to absorb nutrients better and speed up the growth timeline.
In order to fully understand the soil beneath your spruce, it is encouraged that you test the soil. Purchase an at-home soil testing kit or grab some items from your pantry and get testing!
Now as you journey through nature and encounter a forest of spruce trees, you’ll be able to connect with a better understanding of why spruce trees love acidic soil and how to establish an environment at home for one of your own!
References
Badalucco, L., Grego, S., Dell’Orco, S., & Nannipieri, P. (1992). Effect of liming on some chemical, biochemical, and microbiological properties of acid soils under spruce (Picea abies L.). Biology and Fertility of Soils, 14(2), 76-83.
Mund, M., Kummetz, E., Hein, M., Bauer, G. A., & Schulze, E. D. (2002). Growth and carbon stocks of a spruce forest chronosequence in central Europe. Forest Ecology and Management, 171(3), 275-296.
Oostra, S., Majdi, H., & Olsson, M. (2006). Impact of tree species on soil carbon stocks and soil acidity in southern Sweden. Scandinavian Journal of Forest Research, 21(5), 364-371.
Puhe, J. (2003). Growth and development of the root system of Norway spruce (Picea abies) in forest stands—a review. Forest ecology and management, 175(1-3), 253-273.
Schulze, E. D. (1989). Air pollution and forest decline in a spruce (Picea abies) forest. Science, 244(4906), 776-783.
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