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The ideal soil for blueberry bushes is in some ways the opposite of what most fruit plants want. Instead of rich and loamy, blueberries like soil that’s light and lean. Instead of neutral to slightly acidic, blueberries need extreme acidity that would be inhospitable for many plants.
Luckily, it’s possible to adjust a planting site to be blueberry-friendly. Once you understand what a blueberry bush needs from its soil, you can amend your soil (within reason) to provide those things.
I recently ripped out some old, frost damaged, drought-ravaged boxwoods in my backyard to start my own blueberry patch. Blueberry bushes are the perfect edible plant to use in any landscape, since they are as ornamental as the berries are delicious.
Check out the video below to see how I planted my blueberry patch:
What kind of soil do blueberry plants need?
Blueberry bushes need very acidic soil with a pH between 3.8 and 5.5 (ideally between 4.0 and 5.0). They prefer soil that is light and well-draining but consistently moist. Blueberries grow well in lean soil as long as is in the correct pH range there is enough organic matter present.
Planting blueberries actually begins far in advance of even buying the plants – with a soil test. Unless you are sure that your soil is ideal for growing blueberries, a soil test from a reputable testing service (such as your County Extension Office) is essential.
It’s not just about pH, either; you also need to know the amount of organic matter present and a breakdown of the nutrient composition before deciding what amendments to use.
Blueberry pH range
The easiest way to fail at growing blueberries is by having soil that is too alkaline (a higher pH). Blueberries need very acidic soil (pH of 3.8-5.5) because certain essential nutrients only become available to the plant at a low pH level.
For example, in higher pH soils blueberry bushes are often deficient in nitrogen – not because it isn’t there, but because it’s available in the wrong form for a blueberry bush to absorb. Blueberries prefer nitrogen in the ammonia form rather than the nitrate form that is found in more neutral soil (and which most other plants prefer) (source).
Most garden soils fall in the slightly acidic to neutral range (pH of 6.5-7.0). Even where I live, which is pretty “ideal” for blueberries because of the sandy soil and pine forests, my soil only has a pH of about 6.0. In other words, it’s a good bet that you’ll have to amend your soil somehow before planting (see Step 2 below).
Soil Drainage
A key to understanding what blueberries need from the soil is knowing how they grow. The roots of a blueberry bush are very fine and weblike, creating a net close to the surface of the soil. If the soil dries out too much then the roots will also dry out.
On the other hand, the thin roots are very susceptible to root rot in soggy soil. Blueberries must be planted in very well-draining soil. In other words, water should drain through quickly after a rain rather than standing in puddles for a long time.
If you aren’t sure how to check your soil drainage, I wrote an article that covers it: Soil Drainage for Fruit Trees: Everything You Need to Know.
This may seem a little surprising, especially when you take into account the fact that blueberries grow wild in peaty bogs. However, in those spots the blueberries are usually growing on little hillocks between the soggy areas, where the abundance of wetland life keeps the ground nicely aerated. So the wild blueberries have the perfect balance of soil that stays moist, but never soggy.
If you are concerned about the drainage in your planting site, consider mounding up the soil and planting the blueberry bushes a little elevated. Growing blueberries in berms like this is a great solution for clay soils that drain slowly.
Soil Texture and Organic Material
The hairlike roots of a blueberry bush also need soil that is light and porous (space between soil particles). Dense, compacted, or clay soils will be difficult for the tiny roots to penetrate. Think light and fluffy, rather than close and heavy.
An abundance of organic material will help the soil texture (details in Step 2). The amount of organic matter present should be 3% or more – something a good soil test will tell you. In Texas the soils are notoriously lacking in organic matter, so adding some to my blueberry planting site was a top priority for me.
If you are good at planning ahead, consider planting a cover crop such as red clover or annual rye the year before. Tilling a cover crop into the soil is a great way to add organic material.
Step 1: Clear the Planting Area
Before you can amend or plant any blueberry bushes, thoroughly clear away any weeds in the planting area. The fine, surface-level roots can easily be in competition with more aggressive weeds for whatever water or nutrients are present in the soil.
Blueberry bushes need heavy mulching for several reasons, one of which is weed suppression. To protect the web of roots from competition (as well from drying out), keep the planting area mulched year-round.
Step 2: Amend the Soil
The main goals when amending the soil for blueberries are to reach the ideal pH range (between 4.0 and 5.0), improve drainage, and lighten the soil texture by adding organic material. Chances are, by adding what you need to adjust the pH, you’ll also be improving the texture and drainage.
Thankfully, you only need to amend the soil down to a depth of 12 inches. Blueberry roots stay fairly shallow, even when the plant grows to its mature size.
Adjusting the pH of soil takes time, and is only possible to a degree. Your soil will always want to return to its “natural” pH level, so it will be necessary to repeat applications of products and amendments every couple of years. Test the soil around your blueberries every year to maintain the proper pH level.
Sulfur
The best way to make soil more acidic is by applying a product containing sulfur to the soil. I used the Epsoma Soil Acidifier, an organic product which contains elemental sulfur and gypsum. Sulfur needs time to be broken down by microbes in the soil, so apply it at least 6 months before planting blueberry bushes.
Follow the package instructions to determine how much sulfur to apply. For example, Espoma recommends applying the acidifier at the rate of 12-15 pounds per 100 square feet, depending on how alkaline or clay-heavy your soil is.
I have an article that goes into great detail about how to acidify soil for fruit trees and plants. Check it out for more details: Soil pH for Fruit Trees: Why It Matters and How to Adjust.
Peat Moss and Pine Bark
Work a combination of peat moss and partially composted pine bark (also called pine fines) into the planting hole. Sphagnum peat moss has a pH between 3.4 and 4.8. As it breaks down over time, it can help acidify soil, and can even improve soil texture and drainage (especially for sandy soils).
Peat moss works best as an acidifier if you are only trying to make a small shift on the pH scale. Sulfur is a better choice if you need to lower the pH by more than 0.5.
You can replace up to half the volume of the native soil with peat moss – just be sure to pre-moisten the peat moss before planting. Damp peat moss will help with water retention in the soil, but dry peat moss actually wicks water away from the blueberry bush roots.
Blueberries love peat moss and can even grow well in peat moss alone. However, there is some concern about the sustainability of peat moss and the environmental impact of harvesting from peat bogs (read more about that here).
Coconut coir is often used as a substitute for peat moss in other settings (such as for seed starting or making a planting medium). However, coconut coir has a more neutral pH (5.7-6.5), so it won’t help acidify soil for blueberries.
Pine bark is another great addition to a blueberry planting site. It has a pH of 3.7-4.0, so it helps lower the pH of soil as it breaks down. Blueberries often grow near pine trees since both plants need similar soil conditions to thrive.
When I planted my blueberry bushes, I mixed in both dampened peat moss and pine bark with my native soil at a ratio of about 1/4 peat moss, 1/4 pine bark, and 1/2 native soil. I also spread some of the Epsoma Soil Acidifier in and around the planting hole (make sure to keep it away from direct contact with the roots).
Adding peat most, pine bark, or other composted organic material help improve the soil’s drainage and texture. The goal is to increase the porosity of the soil – or the amount of air space, while still retaining moisture. The soil should be light and allow water and air to flow freely.
Step 3: Planting Blueberry Bushes
Dig a hole about twice as wide as the blueberry bush’s pot (aim for 2-3 feet wide) and about 1 foot deep. Place the native soil (that you dug out of the hole) in a wheelbarrow or on a tarp. Mix in any soil amendments, then use the mixture to backfill the hole after planting.
Do not plant blueberry bushes too deep. The tiny roots need to be close to the surface in order to get the moisture they need. Situate the plant so the top of the root ball is at or just below ground level.
Once you’ve planted the blueberry bush, backfilled with the soil mixture, and tamped down to remove any air pockets, water thoroughly. Top the plants with 3-4 inches of organic mulch such as pine bark, shredded leaves, pine straw, or a combination of material.
Does pine straw mulch lower soil pH? It’s a gardening myth that mulching with pine needles will lower the pH of the soil as the needles break down. However, this myth has been debunked – the decomposition process actually neutralizes the pH of pine needles, making little to no difference to soil pH. Read more here.
In the fall, I raked up leaves and pine needles from my lawn, then ran them over with the lawn mower. The resulting mulch was perfect for top-dressing fruit trees – especially my newly planted blueberry patch. Bonus – I didn’t have to bag any leaves!
Step 4: Maintaining the Soil After Planting
Keep mulch around your blueberry bushes year round to suppress weeds, regulate soil temperature, and keep moisture more consistent.
Blueberries can be sensitive to too much fertilizer. If you do need to feed them, a fertilizer made for acid-loving plants can help maintain a lower soil acidity. I like the Fox Farm Happy Frog Acid-Loving Plants Fertilizer.
Do a soil test every year to check the pH level. If it begins to creep up, apply a soil acidifier (sulfur) at the rate recommended on the package as needed.
Links to Additional Resources
WVU University Extension: Growing Blueberries for Beginners
Texas Gardener: Bountiful Blueberries
Penn State Extension: Keys to Establishing a Successful Blueberry Planting
