Written By Lara Wadsworth

Whether you're a seasoned gardener or just getting started, one thing's for sure: the secret to a thriving garden lies beneath your feet. Garden soil fertility is a major contributor to plant health and the overall productivity of your garden each year. Taking control of your soil’s fertility can be simple, but makes a huge difference in your garden. Low soil fertility is when your garden soil lacks key nutrients that are required for your plants to flourish. This can also come in the form of nutrients being present, but the plants being unable to absorb them due to other factors.

Signs of Low Soil Fertility

There are many ways that plants can express distress, but they usually come in the form of slowed or stunted growth, few or no flowers, yellowing leaves, decreased yields (if a vegetable or fruit crop), drooping foliage, or even decreased pest resistance. The nutrients that plants take up influence all aspects of their growth and performance. For example, insufficient nitrogen in the soil will result in yellowing leaves and stunted plant growth. However, other nutrients impact other aspects of plant growth and development.

Common Soil Problems that Affect Soil Fertility

There are many things that influence soil fertility beyond the nutrients in the soil. Compacted soil, poor water retention, poor drainage, low organic matter, and pH imbalances all impact a plant’s ability to absorb nutrients from the soil, if they are there at all. This article will mostly focus on increasing and maintaining the presence of nutrients in the soil. For other soil problems and how to fix them, check out our other blogs! Reading through these blogs and interpreting your soil test results should provide you with the necessary information to proceed with improving your garden's conditions.

Soil Testing to Understand Your Soils Fertility

The first step in determining how to go about improving your garden soil is to understand where it is starting. There are at-home soil test kits that can be purchased online and at local garden centers, but the most reliable test can be done through your local extension office. Simply request a soil test kit or mail your sample with the required forms as determined by your extension office. This is fairly inexpensive and provides you with a wealth of dependable information. For me, this cost about $30 (Michigan State University Extension Services). It is well worth the price for the tailored information it provides.

5 Ways to Improve Soil Fertility

Add Organic Matter to Your Soil

The number one best thing you can do for your soil, pretty much no matter what the issue is, is to add organic matter. If I could write it in gold lettering and attach some confetti or something, I would! Organic matter improves basically everything about soil texture, fertility, and functionality. This can come in many forms, such as compost, worm castings, leaf mold, manure, dead cover crops, and more! Regularly incorporating organic matter into your soil will do wonders for your plants and overall soil health. In addition to adding nutrients directly into the soil, it also adds and supports microorganism activity, which makes nutrients more readily available to plants.

Improving Soil Fertility with Amendments and Fertilizers

Organic matter is definitely the best amendment for soil fertility, but you have some other options to give your soil a boost, too. Other organic fertilizers that can provide nutrients in the short term include bone meal, blood meal, fish emulsion, and kelp meal. Always follow package directions for dilution rates and recommended usages. You can also purchase various fertilizers at garden centers, but it is important to keep in mind that these solutions do not last long compared to adjusting the long-term composition of your soil.

Mulching Your Growing Space

Once you have added organic matter to your soil, mulching is a great way to help retain those nutrients. Mulching cools the soil down, reduces water evaporation, and protects plant roots so that they have the optimal environment for soaking up all those minerals. Using materials like straw, leaves, or grass clippings also helps to suppress weeds and add organic matter back into the soil as it decomposes. Just be sure to allow 2-3 weeks for fresh green plant material to start decomposing before planting into the area, as the decomposition process can temporarily tie up soil nutrients.

Plants for Improving Soil Fertility

It's not always about what you can add to the soil but about what plants you grow. A huge way to improve overall soil fertility is to use cover crops. Cover crops prevent erosion and enrich the soil. The crops grow in the off-season or in soil that is not being used by other plants. Then, when they either complete their life cycle or produce enough biomass to benefit the soil, they can be tilled back into the ground to add organic matter, nutrients, and many other benefits. Cover crops typically include plants like legumes, brassicas, and grains. These cover crops will add vital nitrogen back into the soil for an added boost to soil fertility.

In addition to cover crops, soil fertility can be improved by planting perennials whenever possible. Perennials establish themselves in the soil and are much less demanding on soil nutrients. They typically have deeper roots that break up compacted soil and free up nutrients tied up below the topsoil. Even in decorative beds, consider planting a mix of annuals and perennials to get the look you want, as well as the benefits of perennial roots.

Crop Rotation to Balance Soil Nutrients

Another practice you can implement to improve soil fertility is simply practicing crop rotation. Crop rotation is when you wait a number of years between planting a certain crop in a particular patch of earth or field not to deplete the nutrients too heavily. This also reduces soil-borne disease risk and disrupts pest and disease cycles. All plants take up nutrients from the soil, but different plants are more intensely depleting of particular nutrients than others. For example, it is best practice to wait 2-3 years between planting anything in the nightshade family in the same place they have been grown before. This includes tomatoes, peppers, and eggplants, among others. Mixing up what plants you grow and when and where you grow them is critical for maintaining overall soil health and soil fertility.

There you have it, gardening friends—a comprehensive guide to boosting your garden’s soil fertility. Remember, healthy soil is the cornerstone of a thriving garden. By understanding your soil’s needs, adding the right amendments, and choosing the right plants to grow, you’re well on your way to creating a lush, productive garden that’s the envy of the neighborhood.

Lara Wadsworth, True Leaf Market Writer

I am a native of Southwestern Michigan, where I currently reside. I love all things plants! After completing a Bachelor's Degree in Horticulture, I found a dream work-from-home job that allows me to share my passion. Now, I spend my days writing for TLM, playing with my dog, eating delicious food with my husband, and plotting my next landscape or gardening move. I believe everyone should get down and dirty in the soil now and then. Happy Gardening!