Is Soil Testing Worth It? Basics A Michigan Gardener Should Know

Soil testing isn’t something every gardener has to do, but it can be a helpful tool, especially when you’re getting ready to amend garden beds for spring. Instead of guessing what your soil might need, a soil test determines nutrient levels and soil characteristics that directly affect plant health and productivity.

A basic soil test can tell you:

• Your soil’s pH level

• Whether key nutrients like nitrogen (N), phosphorus (P), and potassium (K) are low, balanced, or high

• If adding lime or other specific amendments would be beneficial

  
  

Where to test

There are various DIY soil test kits you can find at larger home improvement retailers or online that measure nitrogen (N), phosphorus (P), potassium (K), and soil pH, whereas a lab test can measure a host of other nutrients and tends to be more accurate.

Our DairyDoo organic compost supplier, Morgan Composting, provides soil testing for both homeowners and commercial growers. Using your results, they’ll suggest the right amendments for your soil. For large gardens or farms, they can even design a custom soil blend to match your growing goals. View their online form for a list of tests and prices.

https://dairydoo.com/soil-testing-services/

Michigan State University (MSU) Extension provides research-based recommendations for both home gardeners and commercial agricultural producers. For commercial growers, MSU soil test recommendations are also required to remain compliant with the Michigan Right to Farm Act and Generally Accepted Agricultural Management Practices (GAAMPs).

Tests can be purchased online HERE, and your local MSU extension office can assist with any related questions. After receiving your soil test report number, you can then use MSU’s interactive website to customize fertilizer recommendations for the specific plants that you want to grow.

Once you know what your soil needs, you can amend with confidence. With that said, if you decide testing is not for you, simply top-dressing, working in a good quality compost, or using a pre-made soil blend formulated for your bed type (ex. flower, vegetable, rose, trees and shrubs) can greatly improve overall soil quality. 

Understanding Basic Amendments & Fertilizers

Soil amendments are materials (often organic matter) added to improve the overall health and structure of your soil over time, while fertilizers offer a short-term boost of nutrients and help address immediate deficiencies. Amendments work more gradually to create lasting improvements, such as better soil structure, increased water-holding capacity, improved aeration and drainage, and a more-balanced pH. For long-term garden success, priority should be put on building and maintaining a healthy soil ecosystem. 

Following is a quick overview of key soil amendments and fertilizers and how each supports plant health.

AMENDMENTS (improve soil structure)

• Compost: Improves soil texture, drainage, water retention, nutrient levels, and beneficial microbial activity.

• Compost Tea: An all-natural organic amendment brewed from compost that boosts soil microbes. Great for reducing transplant stress.

• Well-composted manure: Increases nitrogen levels and improves soil texture and structure.

• Worm castings: Improve soil aeration and water retention, and help anchor nutrients.

• Agricultural lime: Raises soil pH by neutralizing acidity. Soils with a pH below 6.5 can limit a plant's ability to absorb essential nutrients such as nitrogen, phosphorus, and potassium.

• Sulfur: Lowers soil pH; generally used for acid-loving plants.

  
  

FERTILIZERS (add a boost of nutrients)

Granulated fertilizers release nutrients gradually over time, whereas liquid fertilizers provide a rapid supply of nutrients that plants can absorb more quickly. There are various mixes that are specifically formulated for particular needs. 

The NPK number system on fertilizer labels shows the percentage of three primary nutrients essential for plant growth: Nitrogen (N), Phosphorus (P), and Potassium (K). The percentage number order is standardized; Nitrogen is always the first number, followed by phosphorus, then potassium.

• Nitrogen (N) promotes leafy, green growth, helping plants grow tall and vigorous, and it’s essential for photosynthesis. Too much can cause excessive leafy growth with fewer flowers or fruits.

• Phosphorus (P) supports strong root development and aids in energy transfer within the plant. It is important for flower and fruit production and is especially important for young plants and root crops.

• Potassium (K) improves overall plant health by increasing disease resistance, enhancing drought tolerance, and helping to regulate water and nutrient movement.

A fertilizer labeled 10-5-10 means:

10% Nitrogen (N)

5% Phosphorus (P)

10% Potassium (K)

The remaining 75% is made up of other nutrients or filler material.

Different plants and growth stages require different nutrient balances. Lawns often need higher nitrogen (e.g., 20-5-10), flowering plants benefit from higher phosphorus, and vegetables require more balanced formulas depending on their stage of growth.

Some granulated fertilizer blends we recommend and carry are:

• ALL-PURPOSE 8-4-4 from Morgan Composting: Organic and made with processed poultry manure and Dairy Doo, offering calcium, nitrogen, phosphorus, and potassium.

• Healthy Garden 7-6-5 from Morgan Composting: An organic chemical-free granulated fertilizer safe to use on edible plants, flowers, and in containers and can be spread by hand, spreader, or applicator as needed.

• SAFE GREEN LAWN 10-0-4 from Morgan Composting: An organic granulated fertilizer,can easily be added 3 times a year to help achieve a lush, green lawn. It is phosphorus and chemical free, and is safe to use around kids, pets, lakes, rivers, and streams.

  
  

These can be spread by hand, by broadcast applicator, or by using a spreader.

If you need more immediate nutrition application, you could also use a liquid fertilizer that can simply hook up to your garden hose and spray on. Here are some liquid fertilizer options that we recommend, also from DairyDoo, that you might want to try:

• VeggieBlaster 8-1-8: Promotes nutrient-dense veggies and lush, green foliage.

• FruitBlaster 1-5-13: More potassium improves fruits’ flavor.

• BloomBlaster 4-18-4: Higher phosphorus increases vibrancy and bloom size.

• TurfBlaster 11-0-5: Feeds a boost of nitrogen for a rich, green color.

  
  

Healthy soil is the most important step towards a robust, thriving garden. Start with that, and the rest becomes easy. Happy Gardening!

IMAGE CREDITS:

• COVER: AI-generated image created with DALL·E by OpenAI

• Soil testing: Smartleaf compost soil test results Phosphorus Potash Nitrogen” by Wayan Vota, CC BY-NC-SA 2.0

• Nutrient-poor soil: CC0 https://pxhere.com/en/photo/877751

• Nutrient-rich soil: CC0 https://pxhere.com/en/photo/1407272

• DairyDoo Product images: Morgan Composting, Inc

• Flower garden: Westside Garden Center