Soil Testing and Management of Nutrients In Your Garden

Proper management of nutrients in your garden will help your plants, blossoms, and fruits attain better health and greater beauty. Here is what you need to know about keeping your plants and garden looking their absolute best.

To begin with, only apply the nutrition that the plants in your garden actually need.

There are 20 different nutrients that are commonly needed by plants in the average garden. Phosphorus, nitrogen, and potassium are the most important of these and are needed in large amounts.

  • Nitrogen is important for plants that will produce lush vegetation.
  • Potassium builds robust plants and helps to protect plants from diseases.
  • Phosphorus creates impressive blossoms and fruit.

Then there are other nutrients like calcium, magnesium, and sulfur which should also be applied, in comparatively smaller amounts. These are called the 6 macronutrients.

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Then, there are the micronutrients which are also required but in much smaller amounts. For example, copper, zinc, boron, and iron.

Macro- and micronutrients are both needed for healthy plants, but applying too much of any specific nutrient can have the exact opposite effect and could impair the growth of plants.

Furthermore, the over-application of nutrients could contaminate groundwater supplies and pollute the subterranean water table.

Soil Testing

We've used Luster Leaf's at-home soil test multiple times. It gives you a general idea of the pH of your soil, as well as nitrogen, phosphorous, and potassium levels.
We’ve used Luster Leaf’s at-home soil test multiple times. It gives you a general idea of the pH of your soil, as well as nitrogen, phosphorous, and potassium levels.

A good way to begin your plan for healthy plant nutrition is with soil testing.

Soil testing will allow you to know the pH level of your soil as well as the nutrients present. If you will be planting a garden, having the soil tested would be the best way to begin.

You will find that the cost of a soil test is small in comparison to the pain and frustration of blindly applying nutrients that could be doing considerable damage.

Once you know exactly what your soil contains, you can build off a plan of properly measuring nutrients and ongoing testing to ensure that you are not disrupting the chemical composition of your garden.

Many people are in the habit of liming their garden, but if this is done excessively, it can alter the pH level of the ground to an unsafe degree.

You can find a variety of soil testing kits available on Amazon, at your local supplies store, or gardening centers, but the most reliable results will be found from the Cooperative Extension Service in various land grant universities.

University and other commercial testing services will provide detailed information and allow you to choose even more specialized tests needed when you begin to suspect a problem.

In addition to a simple readout of all the nutrients and chemicals present in your garden, these superior tests can provide you with recommendations for adjusting these levels of nutrients and balancing pH levels perfectly.

PH testing your soil is a very simple thing — pH levels will tell the acidic or alkaline levels of your soil.

If your soil’s pH level is above 7 it is alkaline, below 7 is acidic soil and a pH level of 7 is neutral.

Because the pH level of the soil will greatly influence the nutrient intake of your garden, learning how to adjust this level is essential to providing proper nutrition to your garden.

Iron deficiency is one of the problems that can occur even in soil of a neutral pH level and can be especially detrimental to rhododendrons and blueberries.

If pH levels are lower than this, other problems may ensue including excessive micronutrients that result in plant toxicity. Regular testing can inform you of the correct nitrogen, potassium, and phosphorus levels.

Our Pick
Luster Leaf Rapitest Soil Test Kit for pH, Nitrogen, Phosphorous and Potash
$16.28

This innovative and inexpensive at-home soil test kit features easy-to-use capsules and contains everything you need for 40 tests (10 each for pH, N, P, and K). Great for beginners and experienced gardeners. Includes a soil pH preference list for over 450 plants, which we found very helpful.

Get More Info
We may earn a commission if you make a purchase, at no additional cost to you.
05/20/2022 02:05 am GMT

Nitrogen Testing

There are various ways to test nitrogen in the soil, but not all are the same.

Nitrogen is present in the soil and can take on a wide variety of different forms. For this reason, obtaining a precise analysis of this important nutrient can be more difficult to obtain.

For the most part, most universities don’t routinely test for nitrogen in the soil. On the other hand, it is possible to get an idea of the nitrogen content in the soil by using a home testing kit.

But once again, because of the nature of nitrogen in the soil, it can be difficult to get a precise reading.

Organic Matter Testing

Organic matter is another important part of proper testing.

Organic matter has an important role to play in the quality and structure of the soil and provides a wealth of advantages including aeration as well as the movement of and retention of soil moisture levels.

When the soil is high in organic matter, microbial activity is increased and root growth is encouraged, this allows for a healthier plant.

The organic content of the soil will also allow for better availability of the soil nutrients and improves the way soil reacts to pesticides.

Organic content of the soil also means that the nutrient levels of the soil are far greater than those with lower levels of organic matter.

Micronutrient Testing

There are also tests that will provide you with a readout of the valuable micronutrients in the soil. But these tests are only necessary if there is reason to believe that the soil is deficient in some way or if other problems exist in the soils.

There are also certain plants that have a higher demand for specific micronutrients and when they begin to show signs of malnutrition, a test may reveal the source of the problem.

Blueberries, for example, will suffer from low levels of iron, unless they are planted in soil with lower pH levels. This will be evident in their newly sprouted leaves, which will appear yellow between their veins while the veins themselves will remain green.

If all the other plants growing from the same soil appear healthy, then simply adjusting the pH levels of the soil will often correct the issue.

Taking Soil Samples for a Laboratory Testing

You can use a shovel or soil probe to take samples for soil tests, as long as your sample reaches a depth of around 6 inches.
You can use a shovel or soil probe to take samples for soil tests, as long as your sample reaches a depth of around 6 inches.

If you want to get a soil test done by a local land grant university, begin by contacting the Cooperation Extension Service for more information and the sample bags they use to perform these tests.

If you will be looking for a private laboratory that will do these tests, then contact them and ask about the details they require for submitting a sample.

You will be provided with very specific directions for collecting a proper soil sample.

Here is the process that is typically described for this task:

  • Soil samples should be taken when the soil is damp, but not thoroughly wet.
  • For each acre of land being tested, you will need to collect between 10 and 15 samples.
  • These different samples should be collected from areas that appear different. For example, one sample should be taken from a garden, another from an area that used to be a lawn and another from the current lawn, for example.
  • Use a pail or some other form of clean container.
  • Clear away a section of land from grass and any other litter where you will collect the sample.
  • Use a spade or a soil auger to collect a small amount of soil from a depth of about 6-inches.
  • Place the collected soil in the pail
  • Repeat these steps until all the required samples have been collected.
  • Mix the samples together thoroughly. (Unless you want to know specific results for each area, in which case you should discuss this with the testing facility – you may need to label your samples and keep them separated.)
  • From the pail of well-mixed samples, take the sample that will be sent for an analysis.
  • The sample must be sent for testing immediately, do not allow it time to dry.

Testing With a Home Soil Testing Kit

Home soil testing kits are actually a lot of fun! Our pH was pretty good, but some of the macronutrients were way off.
Home soil testing kits are actually a lot of fun! Our pH was pretty good, but some of the macronutrients were way off.

If you will be using a home testing kit, the aforementioned steps should also be followed for collecting the soil samples. Then, carefully read the instructions provided on the testing kit itself.

These are Luster Leaf’s instructions for our soil test kit:

Luster Leaf's instructions page 1 for the Rapitest Home Soil Test Kit.
Luster Leaf’s instructions page 1 for the Rapitest Home Soil Test Kit.
Luster Leaf's instructions page 2 for the Rapitest Home Soil Test Kit.
Luster Leaf’s instructions page 2 for the Rapitest Home Soil Test Kit.
Luster Leaf's instructions page 3 for the Rapitest Home Soil Test Kit.
Luster Leaf’s instructions page 3 for the Rapitest Home Soil Test Kit.

Applying Fertilizers and Soil Amendments

Let’s take a quick look at how to go about applying fertilizers, and how to amend your soil if it needs it.

Adjusting pH Levels

Once you have received the information from your soil testing, it will be time to begin your plan for adding nutrients, fertilizers, or amendments as needed.

If you need to raise the pH levels of your soil, begin with lime. This is most effective when mixed well into the soil, so it is a good idea to do this before you begin planting.

For very large expanses of land, rototilling is the best way to properly combine the lime into the soil.

In smaller gardens, this can be done with a spade or cultivator. If you already have plants growing in the garden you will need to be careful not to disturb the soil around the plant’s roots.

Depending on the type of lime you use and the conditions of the soil, the adjustment of pH levels could be gradual or very slow. It could take as long as a few months for the pH levels of your soil to be adjusted.

Soils that have a high content of clay will often require larger doses of lime to make a difference than sandy soils.

Our Pick
Jobe's Organics Garden Lime Soil Amendment, 6 lb
$16.19

Organic granular for increasing soils alkalinity, pH; Low pH can cause poor fertilizer response and soil structure.


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05/20/2022 01:26 am GMT

Then there will be the need to reduce pH levels in some cases. This can be done with aluminum sulfate.

Be sure to follow the instructions provided by the manufacturer when applying this to the soil. Once again it is important to thoroughly and carefully mix the aluminum sulfate into the soil.

Our Pick
Fertilome 32175 Aluminum Sulfate Soil Conditioner, 4-Pound
$12.49

Helps create an acid soil condition for plants. Intensifies blue color in hydrangeas. Use on azaleas, gardenias, camellias, rhododendrons, blueberries and others listed on label.

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05/20/2022 08:40 am GMT

Improving the Nutritional Profile

There are numerous ways to improve the nutrient levels of the soil with potassium, phosphorus, and nitrogen. If your soil already contains a balanced nutritional profile, compost is often the best thing for improving the nutritional level of your soil.

Compost

<a class=Compost is one of the best things you can add to your garden. Not only does it keep your soil aerated, it also increases organism activity.” class=”wp-image-17340″/>
Compost is one of the best things you can add to your garden. Not only does it keep your soil aerated, it also increases organism activity.

Compost doesn’t have the same nutritional profile as commercial fertilizers used for improving the quality of the soil, it has a wide variety of other benefits.

For example, compost keeps the soil loose and aerated allowing improved root growth that also improves the nutritional intake of your plants.

Compost also supports other forms of life in the soil and eliminates the presence of pathogens.

Best of all, you can apply as much compost as you want to the soil with only more benefits, unlike other synthetic fertilizers that can “burn” your plants.

Manure

Horses are walking manure machines! The kids and I go out most afternoons to collect wheelbarrows full. I dump the manure on all the gardens and around the fruit trees. I don't compost it before adding it to the garden - I've never had an issue with plants getting burned yet, and I'm all for saving time and effort!
Horses are walking manure machines! The kids and I go out most afternoons to collect wheelbarrows full. I dump the manure on all the gardens and around the fruit trees. I don’t compost it before adding it to the garden – I’ve never had an issue with plants getting burned yet, and I’m all for saving time and effort!

Manure is another great way to improve the quality of the soil with organic matter.

For the best result, manure should be composted before it is applied to the soils. This is because fresh manure can be too strong for the soil and harm the plants.

But manure should also be composted with care especially in large amounts as, if it is exposed to rain, the runoff can be harmful and leach into waterways.

Therefore, you will want to make sure that your composted manure is located away from waterways and hopefully somewhere that the runoff will not be leached into groundwater.

For example, if runoff is sent into a highly vegetated area, it can be safely collected through phytoremediation.

For best results, your composted manure should be carefully worked into the ground. If you will be applying manure before planting, it should be mixed thoroughly to a depth of 8 – 12 inches.

If plants already exist the same should be done, but care must be taken to not disturb the roots of the plants.

Green Manure

digging green manure into the soil
Digging green manure into the soil

Then there are green manures that can provide an organic form of plant nutrients. Green manures are worked into the soil as well and as they decompose, they release nutrients for the plants and tie the ground together preventing soil erosion.

Some examples of green manures include oats and rye which are planted in late fall and then tilled into the ground in the spring before planting.

Commercial Fertilizers

/NOMINATED/ Fertilizer for grass, lawn, meadow in a bag of white granules on green grass.
Commercial nitrogen, phosphorus, and potassium fertilizer

Finally, there are commercial fertilizers that provide nitrogen, phosphorus, and potassium at different levels according to the needs of the location.

You will typically see these labeled with a set of numbers like “10-20-10″. The first number indicates the amount of nitrogen (N) in the fertilizer, the second shows the amount of phosphorus (P) and the last is the amount of potassium (K).

The fertilizer you select should be chosen based on the needs of the soil as indicated by soil testing results.

These exist in granular or liquid form and should be added to the soil according to the manufacturer’s instructions.

Final Thoughts

I highly recommend you have a proper soil test done, at least once. You’ll get an amazing amount of super-specific information about your soil, which means you’re no longer “flying blind” – you have a roadmap to economically improving your soil.

You can’t really go wrong with the organic amendments like manure, compost, green manure, cover crops, etc. – the rule here is pretty much “as much as possible”.

However, once you start working on micronutrients, in particular, it’s easy to “stuff” things up and waste money in the process.

A soil test tells you exactly what’s lacking, and how to fix it.

If a commercial soil test is too expensive or not available, at least give Luster Leaf’s test kit a go – we got some great, eye-opening results!

Our Pick
Luster Leaf Rapitest Soil Test Kit for pH, Nitrogen, Phosphorous and Potash
$16.28

This innovative and inexpensive at-home soil test kit features easy-to-use capsules and contains everything you need for 40 tests (10 each for pH, N, P, and K). Great for beginners and experienced gardeners. Includes a soil pH preference list for over 450 plants, which we found very helpful.

Get More Info
We may earn a commission if you make a purchase, at no additional cost to you.
05/20/2022 02:05 am GMT
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