Top soil amendments to boost plant growth

In order to have a healthy garden, you need to have healthy soil. Healthy soil can better provide plants with nutrients, resulting in plants and gardens alike that are healthier. The soil that contains introduced nutrients that feed the plant is crucial to plant growth, but bad soil can limit what nutrients a plant can access. In these cases, there is a need for soil amendments.

Soil amendments are substances you add to soil in order to change or improve it and to help plants grow better. They are trying to build a better root structure. Soil amendments can be organic, such as compost, or inorganic, which supply certain nutrients depending on what the plants require.

Growcycle offers a variety of soil amendments to help gardens thrive. This article will explain everything about soil amendments and highlight popular options for healthier, more productive plants.

What Are Soil Amendments?

Soil amendment is anything that serves to improve the physical condition of the soil, such as water retention, permeability, water infiltration, drainage, aeration, and structure. Certain amendments provide nutrients, help retain moisture, and ensure the proper pH. These are the transformations that make a healthy and energetic garden or lawn.

Soil amendments are an ideal way to turn a garden or lawn around. The following are primary categories of soil amendments.

• Organic Soil Amendments

Organic soil additives are derived from nature. They are good for soil organic matter and have many benefits. There are all kinds of organic amendments that one might use, but the most popular one is compost. With continuously growing systems, the incorporation of organic matter in the form of humus aerates the soil, promoting the entry of water and aeration, and in the long run, the capacity of water and nutrient retention.

Most organics also contain nutrients and serve as both a nutrient product and an organic slow-release fertilizer. Soil-dwelling bacteria, fungi, and invertebrates also feed on organic matter.

• Inorganic Soil Amendments

Inorganic soil additives are formulated for specific plants. These, however, are used frequently by, and are ideally suited for, homeowners or gardeners, especially if specialty growing plants are intended for the type of garden being landscaped and developed.

Inorganic amendments are typically best for rock and crevice gardens, tree and cactus gardens, and those areas that will be subject to foot traffic or automotive traffic.

Types of Organic Soil Amendments

Organic soil amendments are natural ways to meet plants' nutritional and other requirements. Here are the common types of organic soil amendments.

1. Compost

Compost is a versatile soil amendment for organic vegetable gardens, lawns, and ornamental beds. It is packed with many vitamins and minerals that plants require, helping plants grow more quickly, produce more in the harvest, and become naturally resistant to pests and diseases.

Compost can help to reduce compacted or poorly draining soil, increase beneficial microbial and earthworm activity, and improve soil health and structure. For natural weed control, compost can be applied as mulch and a top dressing to garden beds. Moreover, compost is among the least expensive soil additives available.

2. Manure

Manure is among the best soil amendments for all purposes. It is abundant in the nutrients plants require, can improve the soil's porosity and structure, and increases the activity of helpful microbes.

Gardeners can apply fresh manure directly on the soil or apply compost beforehand, but be aware that certain fresh manures can burn plant tissue. So, gardeners should only use fresh manure in their gardens in the fall following plant harvest.

3. Blood Meal

Blood Meal is one of the best sources of nitrogen for plants. Nitrogen plays an essential role in photosynthesis and keeping the plants green. After mixing it into the soil, blood meal encourages lush, vegetative growth and beautiful leafy greens. It is particularly suitable for producing maize, with an NPK ratio of 12-0-0 to 13-0-0.

In addition to its fertilizer use, blood meal is commonly used as a pest deterrent to keep rabbits and deer away from the area because they are afraid of the stench. Homeowners can till 3 to 5 pounds of blood meal per 100 square feet of garden soil. It can also be sprinkled on plants or used as a side dressing to keep pests away from plants.

4. Feather Meal

Feather meal is another animal-based soil amendment that functions similarly to blood meal. It is a high-nitrogen fertilizer with an NPK ratio of 13-0-0 and is absorbed by garden soil quickly, so it is the best alternative to feather meal.

Since feather meal is not water-soluble like blood, gardeners must mix it into their soil before planting. Because of its high nitrogen content, feather meal is perfect for heavy feeders like:

• Corn
• Melons
• Brassicas

5. Bone Meal

Bone Meal has an NPK ratio of 4-12-0 and is a rich source of phosphorous and nitrogen. It is among the most outstanding options for large flowers and robust root growth. Therefore, it's no surprise that gardeners frequently add bone meal to the planting holes while planting carrot seeds and other root crops.

In addition to being high in calcium, bone meal can help to prevent problems like blossom end rot. Gardeners may need to reapply it on the soil because it is a slow-release fertilizer that may take up to four months to absorb fully. Additionally, bone meal is occasionally sprinkled in the holes when planting bulbs.

6. Alfalfa Meal

Alfalfa Meal is another excellent soil amendment. It is high in potassium and nitrogen, with an NPK ratio of 2.8-0.5-3.6. It is a popular choice for vegan farmers and can frequently be purchased in large quantities to minimize costs. Although animal fertilizers can smell unpleasant, the Alfalfa meal is a top choice for being one of the best-smelling amendments available.

Additionally, its smell is far less likely to draw predators who will plow through the garden for blood or bone meal. The best way to apply alfalfa meal is to use two to three pounds per 100 square feet of growing space.

7. Kelp Meal

Kelp Meal is another nutrient-rich organic soil amendment with an NPK ratio of 1.0-0.1-2.0. Its main advantage is that it is a rich source of:

• Enzymes
• Amino acids
• Trace minerals

All these compounds can assist plants in growing more robustly and improving the nutrient content of food crops to ensure healthier vegetables and fruits.

Kelp meal, made from dried and pulverized seaweed, is especially beneficial for soil low in sulfur or boron. Brassicas, such as cauliflower and Brussels sprouts, enjoy kelp food. The best way to apply kelp meal is to pour 1 pound per 100 square feet of garden space.

Types of Inorganic Soil Amendments

Inorganic soil amendments are mineral-based or manufactured materials to improve soil quality or provide specific nutrients for plants. Here are the main types:

1. Lime

Lime is a soil amendment made from ground limestone rock, which naturally consists of calcium and magnesium carbonate. When lime is added to soil, these compounds increase the soil's pH, making it less acidic and more alkaline. Even though lime contains calcium and magnesium necessary for good plant growth, it is not a substitute for fertilizer. Its principal function is to change soil pH and offset soil acidity, improving plant nutrient availability.

Lime is necessary for lawns when low soil pH limits nutrient availability. Warm-season grasses may tolerate a slightly lower pH, but cool-season grasses prefer a slightly higher pH. Even abundant nutrients are limited when the pH strays too far in either direction. Lime restores equilibrium in too-acidic soil, returning pH to appropriate growing levels.

2. Gypsum

Gypsum is another inorganic sulfate mineral used by gardeners as fertilizer or produced as powder and added to concrete and plaster. Different impurities and other inclusions can give gypsum minerals different colors, such as:

• White
• Gray
• Pink
• Brown
• Green

Gypsum helps boost plant nutritional requirements, improve soil structure, balance pH, and lower aluminum toxicity. Shops typically sell gypsum for gardening as pellets or granules, either white, gray, or brown.

3. Perlite

Perlite is made from amorphous volcanic glass and is often used in gardening to amend soil. Its soil is mixed into potting and plant beds to increase aeration and drainage, avoid soil compaction, and encourage healthy root development. Its lightweight design and water-retention capabilities are excellent for container gardening and potted plants. 

Using equal parts perlite, peat moss, or coco coir, gardeners can improve moisture retention and avoid root rot and other fungal diseases. This promotes overall healthy plant growth.

4. Claying

Claying is the process of adding clay rich subsoil into water-resistant topsoil to overcome the water-repellent soil restriction. Clay can decrease soil water repellency, including long-term impact, improve soil water retention, reduce wind erosion, decrease the risk of frost, improve soil organic carbon, and improve soil structure and plant establishment.

Moreover, claying can help sandy textured topsoils with less than 5% clay concentration, where water repellence is a barrier to crop and pasture growth.

5. Vermiculite

Vermiculite is a mica-like material used as a soil amendment. It is extracted from the earth, exfoliated, and processed with tremendous heat and pressure. The resulting worm-like, curled, and sterile product can grow. Its capacity to expand allows it to retain moisture in the soil, while its porous surface and distinctive shape capture nutrients for plants to use as needed.

Vermiculite lightens thick soils, creating a better environment for plant roots. Additionally, vermiculite is sterile, so gardeners don't have to worry about hazardous plant infections.

Things to Consider While Choosing a Soil Amendment

It is vital when working to enhance the health of the soil and to promote the growth of plants to select the most appropriate soil amendment. Here’s what to know:

Check the Soil’s pH

Soil pH indicates if the soil is acidic, neutral, or alkaline. Plants develop best when the pH is at the level they require. Lime can be used to raise the pH of the soil if it’s too acidic. If it is too alkaline, sulfur can decrease it. Testing the pH can aid in making the correct decision.

Think About the Purpose

Various amendments address various problems. Compost, for instance, enhances the soil structure overall, and perlite enhances the drainage. Understanding whether the objective is drainage, increased water-holding capacity, or a leaching of nutrients will guide the selection of amendment.

Match the Plants’ Needs

All plants have their requirements. Certain plants do better in acidic soil, some prefer alkaline soil. Selecting the correct amendment for the grown plants gives them the best environment for blooming.

Choose Between Organic and Inorganic

Organic amendments such as compost or manure improve soil over the long term, adding organic matter. Inorganic choices such as gypsum or synthetic fertilizers tend to act faster, though they may require more frequent application. Choosing between these options is based on how quickly you want results and your long-term goals.

Think About Long-Term Effects

Soil takes a long time to improve with organic amendments, but it’s long-lasting. On the other hand, inorganic amendments react instantaneously, but may require repeated application. The selection of the proper type is based on whether one wants an immediate remedy or a long-term fix.

Consider Environmental Impact

It is also critical to choose amendments that are environmentally safe. Additionally, synthetic options can be damaging to soil and water, while organic ones are typically environmentally friendly. To choose wisely is to help protect the environment.

Budget and Availability

Cost and practicality also emerge as considerations in choosing an amendment. Many of these organic alternatives can also be produced for free at home, such as compost. For others, look for something cheap and easily available.

Best Practices to Apply Soil Amendment to Garden

The following is the process that a gardener will have to take in applying soil amendment to a garden:

1. Test the Soil First

Before amending, test the soil. A soil test indicates pH, nutrient levels, and the type of soil. That piece of information helps to select the correct correction and apply the appropriate number of it.

2. Choose the Right Amendment

Choose an equivalent amendment for the terrain your garden needs. Compost is good for soil structure; lime is for pH. Which one you choose will depend on the types of plants you are growing and the quality of the soil.

3. Prepare the Soil

Loosen the soil by digging or tilling before applying amendments. This allows the material to mix well and reach plant roots more effectively. Remove any weeds, rocks, or debris to ensure the soil is ready for improvement.

4. Follow Recommended Application Rates

Apply soil amendment at the recommended rate for product use or as determined by a soil-test report. The overuse can be damaging to plants and soil, but too little might not work.

5. Apply Evenly

Spread the amendment evenly across the garden. For smaller areas, work with a shovel or hand tools. If you have a bigger garden, think about using a spreader. Don’t forget to mix the amendment really well into the soil, as that’s what makes the amendment effective.

6. Water After Application

After application and incorporation of the amendment, water the area lightly. This settles the material into the soil and encourages nutrients to become available to plants.

7. Apply at the Right Time

Amendments are best added prior to planting - either early in the spring or late in the fall. This delivers excellent tillage action to let the soil breathe and prepare for the following planting season. For plants already in the ground, use amendments sparingly at the base of the plant.

8. Monitor and Adjust

Take a look at the plants and soil after amending. If plants are stressed or growing poorly, change the type or quantity of amendment on subsequent applications. A farmer might get better results through regular soil testing and fine-tuning.

Common Mistakes to Avoid while Applying Soil Amendments

Here are some common mistakes gardeners should avoid when applying soil amendments to the soil:

• Applying amendments without knowing the soil requirements can lead to harmful consequences. Therefore, a gardener should conduct a test to see the soil pH and other requirements.

• An excess of organic or inorganic substances can disturb the activity of soil microbes and pollute runoff. As a result, homeowners are cautioned against over-applying soil amendments.

• Gardeners may misapply soil amendments, leading to nutrient washout. So, it is better to use soil amendments during the early spring or fall.

• However, if you are misapplying soil amendments (or if you leave some room when applying soil amendments), you aren’t going to get the results you want. So gardeners need to mix the amendment well with the soil.

• Excessive amending of soil with synthetic or inorganic materials, like peat moss, may have negative environmental impacts. Hence, gardeners should resort to organic matter rather than chemicals to amend the soil.

The Bottom Line

Soil amendments are the best way to get the most out of your plants by increasing nutrient availability, water retention, and microbial activity. Gardeners have the choice to apply either organic or inorganic soil amendments based on soil needs, and for the possibility of achieving a more robust and healthier garden or lawn. But timing those applications right and striking the right balance of amendments will mean a healthier garden for you all year long.

Growcycle offers the best soil amendment options, including inorganic and organic plant nutrients to meet the nutritional requirements of soil and plants. Growers can buy soil amendments from their marketplace to have a lively garden.

About the Author

Victor Miller

Environmental Journalist Focused on Sustainable Agriculture

Victor Miller is an environmental journalist at Growcycle, where he covers the latest news, trends, and innovations in sustainable agriculture. He has a deep passion for storytelling that emphasizes ecological balance and responsible farming practices.