Soil Testing and Management of Nutrients In Your Garden

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

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

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:

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

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

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

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

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

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

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

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.

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01/16/2022 07:16 am GMT