If you’re growing blueberries, you’ll agree that they not only taste great but look fantastic in the garden. Getting a good harvest from your blueberry garden starts with suitable soil. There are different techniques for getting any soil in better condition.
Here are 6 tips you can use to improve the soil for your next batch of blueberries:
- Start with a soil test.
- Prepare the planting area.
- Add compost to the soil.
- Set the right nutrient levels.
- Have the correct pH.
- Cover the soil.
Blueberries offer so many health benefits and are relatively easy to grow. One of the critical factors in a bumper blueberry yield is to ensure that your soil enhances growth and fruit formation. If you want to provide the best soil for your blueberries, here are 6 easy methods to try.
1. Start With a Soil Test
Improving your soil starts with understanding what kind of soil you have in your growing area. A simple soil test can give you general knowledge about what’s inside your soil. The goal is to find out whether the soil is fit for growing blueberries and what you can do to improve it if it is not.
There are two ways of testing your soil:
- Using a home soil test kit.
- Sending a sample of your soil to a soil test lab.
Home soil test kits give you instant results about the general picture of the condition of your soil. They are available at most garden shops and convenience stores. There are also plenty of soil test kits online, such as this Kensizer Soil Tester from Amazon.com.
The most basic soil test will uncover things like the pH and nutrient levels of the soil.
pH Levels
pH, or potential of hydrogen, measures how acidic the soil is. The measurements run from 0 to 14, with 0 being the most acidic and 14 the least acidic. The neutral spot is 7, which is typically the pH of pure water.
The natural amount of acid in the soil is usually determined by the type of rock that makes up the soil. The climate, vegetation, and organic matter of the soil can also affect the pH of the soil. Most plants grow in almost neutral soil, not blueberries.
Blueberries thrive in acidic soil, preferably at a pH between 4.5 and 5.5.
Nutrient Levels
The second thing that a soil test will reveal is the minerals in the soil. Blueberries, like all plants, require a mix of macro and micronutrients to survive. Macronutrients are needed in plenty, whereas micronutrients are required in small amounts.
Soil macronutrients include:
- Sulfur
- Magnesium
- Phosphorus
- Calcium
- Potassium
- Nitrogen.
Soil micronutrients include:
- Boron
- Iron
- Copper
- Molybdenum
- Manganese
- Zinc.
The essential nutrients that a soil test will tell you about are nitrogen, phosphorus, and potassium.
You can find out your soil’s pH and nutrient levels by following these steps:
- Get a clean plastic basket that you will use to collect your soil samples. Ensure that it is dry before loading any samples.
- Clean up the site where you’ll be collecting samples. Remove any debris, organic matter, and foreign objects from the area. Before collecting samples, make sure that the soil is not overly wet.
- Pick a spot on your sampling area and dig a V-shaped hole up to 6 inches (15.24 cm) deep. Scoop a 2-inch (5.08-cm) soil sample and place it in the bucket. As you dig, avoid using instruments made of steel, copper, and other metals. These may have mineral residue that could distort the quality of the soil sample results.
- Pick another spot and obtain a sample the same way as the first. Collect 5 to 10 samples, following a zig-zag pattern on the sampling space. Place all samples in the same bucket.
- Mix all the samples in the bucket using your hands. Ensure your bucket is large enough for you to mix the contents easily.
- Conduct the soil test by following the instructions on your soil test kit. This procedure is relatively simple if you follow the instructions.
If you are using a soil test laboratory, send your sample to the lab on the same day. The testing centers will typically send you a prepaid mailer to place your sample.
It takes about 4 to 8 weeks to get the test results with test labs. The upside is that you will get a comprehensive lab report that shows a detailed list of nutrients, water content, pH, and other parameters about your soil.
Soil Texture
Soil texture refers to whether the soil is loam, sandy, or clay. Soil has plenty of minerals that come from different particles in it. Soil texture is determined by the amount of sand, silt, and clay particles that make up the minerals in the soil.
Heavy soils typically have a high amount of clay, while light soils usually have a more significant percentage of sand particles. The texture of soil has many implications, and it can affect:
- The water content in the soil.
- The rate at which water moves through the soil.
- The fertility of the soil.
- The aeration of the soil.
Blueberries love sandy, loamy soil that is well aerated. Clay soils can also support blueberries if they have a relatively high organic matter content.
2. Prepare the Planting Area
Your test results might have indicated that you need to do some work on your soil. However, before you get to that stage, you need to get your soil ready for those adjustments. If you sent your sample to the lab, this is the time to make these preparations as you wait for the test results.
Eliminate Volunteer Crops
If you’ve been using your land for growing blueberries or other plants in the past, you might see a few volunteer crops. These are plants that you did not intentionally plant but, for some reason, happen to be there in the garden.
Volunteer crops come from blueberry seeds that dropped from the previous group of plants growing in the garden. In normal cases, these are fine to leave in the garden.
However, volunteer crops might crowd your next batch of plants if they’re left in the garden. Even more importantly, they could be infected with a disease that could spread to the new, healthy plants. Ensure that you inspect the volunteer plants for signs of disease or parasites.
Remove Debris From the Soil
If you have rocks, debris, or broken plant roots and shoots in the soil, get rid of them. If it is a large piece of land, this might take some time and effort, but it is worth your while in the end. Use a garden rake for the small stones and objects. You can handpick the larger ones to get them out of the soil.
Break Up Clods of Soil
Split up large masses of soil in the garden plot. You may use your hands or another garden tool such as a pickaxe or garden fork. If the ground has hardened up, you can ease this process by watering it before breaking up the chunks if the ground has hardened up. Blueberries thrive in aerated and loamy soil, and these conditions will promote growth.
Create a Raised Bed
If you are growing your blueberries in the open, you should look into setting up raised beds. A raised bed is a temporary heap of soil set up above the rest of the plot. It can also be a mound of earth within a barricade of treated wood, plastic, stones, or concrete blocks.
Temporary beds are easy to build, but they are not very long-lasting. They are prone to crumbling due to erosion or the planting process. Contained beds are more effective because the barricade walls hold the soil in place, protecting it from disintegrating.
Create an Edge on the Garden Bed
If you’ve removed weeds from your planting bed, the last thing you want is for them to come back. You can stop grass from creeping back into the garden by creating some edging around the garden.
You can use large stones to create boundaries where you can plant the blueberries neatly. Be sure to sink them reasonably deep into the soil to prevent weeds from growing underneath them.
3. Add Compost to the Soil
Compost is good for the soil. It helps it to retain moisture and build up valuable fungi and bacteria that break down organic nutrients for your blueberries to use.
Compost should be dry, have an earthy smell, and crumble the same way soil does. If the compost has an unpleasant odor, it is not yet fit for use.
Compost is usually easy to make, but you need to pay extra attention if you’re making it for blueberries. The reason is that blueberries require an acidic medium to grow, so you have to make your compost acidic. Acidic compost is commonly known as ericaceous compost.
Making ericaceous compost starts with creating regular compost first and then making it more acidic over a while. You, therefore, have to keep testing the pH of your compost along the way to ensure it is at the optimum level.
As you make your regular compost, remember to keep a balance of green and brown material. Aim for a ratio of 3:1, respectively.
Green materials provide nitrogen and protein to the compost. They support the growth of microorganisms in the compost pile, and by doing so, they raise the temperature of the compost.
Browns are rich in carbon and carbohydrates. These materials bulk up the heap, provide aeration and act as a food source to the microorganisms.
Your compost should also remain moist at all times. It should be large enough initially, and remember to mix it now and then.
When the compost starts to break down after a couple of weeks, you need to take action to prevent it from losing its acidity. This stage is when you need to reduce the amount of manure, lime, and ash in the mix.
On the other hand, add these items to make the heap more acidic:
- Sawdust
- Wood shavings
- Fall leaves
- Citrus peelings
- Sulfur granules
- Tree twigs and bark chippings.
Whenever you add compost to the soil surface, it will eventually mix up with the soil and ultimately lose some of its acidity. You, therefore, need to constantly check the pH of your soil to make sure it is in the required range of 4.5 to 5.5. If becoming less acidic, simply add more acidifying material.
If your soil predominantly has a clay texture, peat moss may balance the texture and reduce acidity.
4. Set the Right Nutrient Levels
Blueberries do not need to be overly fertilized. Because they adapted to growing in acidic soil that is naturally low in nutrients, too much fertilizer can be detrimental to their growth. It can cause salt burn in their roots, leading to your plant’s failure to absorb nutrients.
The major macronutrients for blueberries are nitrogen, phosphorus, and potassium. Blueberries will also utilize iron, calcium, manganese, and other elements but in trace amounts.
Nitrogen
Unlike most plants, blueberries obtain their nitrogen from ammonium compounds. In alkaline soil, nitrogen is more abundant in nitrate form. But in acidic soil, it is more readily available in ammonium compounds.
Therefore, blueberries are sensitive to nitrate fertilizers, and too many nitrate ions can damage the plant. If you are looking to supplement the soil with nitrogen, go for ammonium sulfate, diammonium phosphate, and urea. If you must use a nitrate fertilizer, go for slow-release nitrogen fertilizers.
Phosphorus
Phosphorus plays a part in root growth and the transfer of energy in the plant. It helps blueberries form proteins necessary for the development of new fruit.
Despite its importance, there is a low amount of phosphorus in acidic soils, especially in land where blueberries have never been grown. If your soil test results showed a low phosphorus content, these are some of the things you can add to give it a boost:
- Seaweed
- Bone meal
- Coffee husks
- Sphagnum peat.
However, high quantities of phosphorus can prevent iron from being absorbed by the plant. You might also want to steer away from rock phosphate because its high calcium content will make the soil more alkaline.
Potassium
Potassium is essential in water movement and photosynthesis in the plant.
Blueberries need potassium, albeit in small quantities. The plants are sensitive to some fertilizers, so tread carefully when adding a potassium fertilizer. For example, blueberries are sensitive to potassium chloride, which can burn the plant.
A great alternative is banana peels. Use the peels in your compost or shred them and include them in your mulch. Banana peels dropped into the garden while still fresh will most likely attract small rodents and insects, so allow them to degrade before adding to your garden.
Magnesium, Calcium, Iron, And Zinc
Magnesium and calcium tend to compete to be absorbed by the plant roots. When one is more than the other, the other struggles to get into the plant through the roots. If you notice a magnesium deficiency, it is because calcium uptake is more prioritized. Epsom salts balance the deficit if applied in large quantities.
Also, if your soil has a high pH, it likely lacks iron and zinc. These two nutrients are abundant in nearly neutral soils but deficient in acidic soils or when there’s an excess of phosphorus.
5. Have the Correct Ph
As you might remember, Blueberries grow well in acidic soils with a pH of 4.5 to 5.5. In most cases, you will need to lower the pH of the soil to get it to the proper acidity levels. Most plants comfortably grow in slightly acidic to slightly alkaline soil, which most soil is.
How to Lower pH
You can quickly lower soil pH by using sawdust, fall leaves, or wood shavings. However, these will only keep the soil acidic for short periods. To get a more long-lasting effect, use sulfur.
There are two forms of sulfur that will lower the soil pH:
- Elemental sulfur
- Ammonium sulfate.
Ammonium sulfate is a synthetic fertilizer that readily mixes with the soil. Although it quickly gets diluted after a heavy downpour, its effects last longer overall.
On the other hand, elemental sulfur needs to react with natural soil bacteria to release the sulphuric acid that lowers soil pH. This reaction time is why it takes much longer to make a change on your soil.
So, how much sulfur to add to your soil? It depends on the type of soil and how much acidity it needs, for starters. For example, sandy soil needs less sulfur than clay and loam soil.
Another chemical you can use to lower pH is Ferrous sulfate. The only disadvantage is that you will have to use nearly ten times the amount you use with elemental sulfur. Nonetheless, it reacts much more quickly.
Aluminum sulfate can also make the soil more acidic, but use it with caution. If used in high quantities, it can be toxic to your blueberries. You may use very dilute sulphuric acid to acidify the soil if you are short on time. The only risk it creates is corroding your irrigation pipes.
The table below shows the amount of sulfur per acre required to lower pH to 6.5.
| Original pH | Sandy soil | Clay soil |
| 8.5 | 0.7 – 1.0 | 1.0 – 1.3 |
| 8.0 | 0.5 – 0.7 | 0.7 – 1.1 |
| 7.5 | 0.2 – 0.3 | 0.4 – 0.5 |
It is recommended that you apply the elemental sulfur a few months before planting. This time span will give it ample time to mix with the soil and make the changes you want. The sulfur reacts with bacteria in the ground to convert it to sulphuric acid.
The optimum conditions for bacteria to make this happen is when the soil is warm and moist.
How to Raise pH
Although it is rare, the soil you’re dealing with may be too acidic – even for blueberries. In this case, you can raise the pH using agricultural lime. It comes as a powder, granules, pellets, and sometimes liquid form.
Powdered lime is more effective because it easily mixes with the soil and sets up the reaction quickly. Apply the lime a couple of months before you plant to give it time to shift the pH entirely.
Wood ashes can also make your soil less acidic, although they take much longer than lime.
6. Cover the Soil
Covering your soil has many benefits. It stops weeds from growing, giving your blueberries exclusive access to the soil’s nutrients. Mulching also helps keep moisture in the ground while protecting the roots of your plants.
If you’re using organic mulch, it provides nutrients to the blueberries when it decomposes.
However, animal manure in compost, such as from chickens, has the disadvantage of creating high pH levels and excessive potassium in the soil.
If the blueberries absorb this much potassium, it can reduce yields in the future. The safest thing to do is regularly monitor the pH and potassium levels. Also, stick to material that does not raise the pH level when you’re mulching.
Saw Dust
Sawdust is a good option for covering the soil for blueberries. However, it would be best never to use fresh sawdust because it attracts nitrogen from the ground. This leaching action will eventually make a nitrogen deficiency for the plants.
Add half or twice the fertilizer you would typically use to solve this. Do this for the first two years to make up for the nitrogen loss.
Composted Sawdust
Composted sawdust is a better option than fresh sawdust. It won’t increase pH, and it will add nutrients to the soil as it decomposes more easily. Softwood varieties that are slightly decayed will make the most effective mulch for your blueberry patch. Composted sawdust also helps retain moisture and keep your plant roots cool in summer.
Weed Mat
A weed mat is a sheet of woven polypropylene that protects the soil from direct sunlight. As it does this, it also prevents weeds from growing in the ground, hence the name weed mat. Planting blueberries in a rainy climate can be a huge plus because it saves you time and money on weeding your garden.
On the downside, it might attract certain critters such as voles as they try to hide away from predators. These might cause problems with the movement of water and fertilizer in the soil.
Hybrid Mulch
Hybrid mulching involves placing a layer of organic mulch underneath the weed mat. Although it is more costly to set up, it saves you a lot in maintenance and material costs. The weed mat preserves organic material underneath, making it unnecessary to keep making replacements. The mat also prevents the mulch from drying too quickly and aids nutrient uptake.
Final Thoughts
Blueberries are fun to grow but require you to work on the soil first. The best way to improve your soil is by carrying out a soil test first. It gives you an idea of how to boost the soil’s performance when it is time to grow your blueberries. Healthy and nutrient-rich soil is the key to a bountiful harvest of delicious blueberries
