Soil Amendment Vs Compost

Those who already have or want to convert their backyard into a garden are faced with the age-old choice of using soil amendment vs. compost.

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Those who already have or want to convert their backyard into a garden are faced with the age-old choice of using soil amendment vs. compost.

You can buy the best seeds and plants for your garden, but if you use the wrong soil, you're likely not going to get the best results. This is why you need to know whether soil amendment or compost to get the most out of your plants.

It is important to note that compost tends to release its nutrients slowly over time, providing the necessary nutrients for your plants. On the other hand, a soil amendment or soil conditioner is a product that you add to the soil later on to improve the soil's physical qualities.

It goes without saying that while you need both to get the best results out of your vegetable garden in the form of healthy plants, flowers, fruits, and vegetables, a soil conditioner is used as an add-on, while compost is a necessary component of any garden.

With years of experience in gardening and horticulture, we can help guide you through the process of using the best compost and soil amendment for your garden, as well as the advantages and disadvantages of both.

Table of Contents

Soil Amendment vs. Compost

Poor soil conditions can harm plant development and health. Plants can dry out, impede their development, and die due to a combination of conditions such as sandy soil, nutrient depletion, low or high pH, and other factors. On the other hand, compost and soil conditioners can increase soil quality and plant development in diverse ways.

Simply put, compost is decomposed organic materials. It's used to boost the nutritional value of new or existing soils. Compost can also be used as a nutrient-rich soil conditioner. Soil conditioners are additives to the soil that improve the structure or physical qualities of the existing soil. It improves soil aeration, water retention capacity, oxygen penetration, and nutrient absorption.

It also has the ability to maintain the pH level. The particle size is one of the main distinctions between compost and soil amendment. Compost is made up of finer materials and is often dug into the soil, whereas soil conditioner is made up of smaller particles.

Soil Amendment

Poor soil can refer to a variety of issues. It can refer to compacted and hardpan dirt, soil with a lot of clay, highly sandy soil, lifeless and nutrient-depleted soil, soil with a lot of salt or chalk, soil or rocky soil with a very high or very low pH. You may be affected by simply one or a mix of these soil conditions.

Most of the time, these soil conditions aren't discovered until you're digging holes for new plants or even after they've been planted and aren't doing well. Bad soil can limit plant water and nutrient intake, as well as root development, leading plants to wilt, dry up, become stunted, and even die. Poor soil, fortunately, may be improved using soil conditioners.

Soil conditioners are substances that minimize water erosion while also improving the soil's quality. Some of the conditioners used to reduce water erosion include flue gas desulfurization (FGD) gypsum, phosphogypsum, and PAMs. Although these conditioners haven't been frequently used in agricultural areas, they're gaining popularity as erosion control choices.

Soil conditioners are soil additions that enhance the structure of the soil by improving aeration, nutrient availability, and capacity for water storage. They soften compacted, clay, or hardpan soils, allowing nutrients to be released. Depending on what they're constructed of, soil conditioners can also boost or drop pH levels.

Plants require 50 percent organic or inorganic material, 25 percent air space, and 25 percent water space in their soil. Clay, hardpan, and compacted soils lack the required air and water space. A part of the organic matter in healthy soil is made up of beneficial microbes. Many microbes cannot thrive without adequate air and water.

Types of Soil Amendments

In case you were wondering, there are various types of soil amendments that you can use for your garden. The following are some of the options:


Dolomite helps increase the pH and release Calcium and Magnesium trapped in the acidic soil. It may be used in lawns and garden beds. In garden beds, spread 250 grams of dolomite per square meter and work it into the top 7 cm of soil. Every other year, apply 125 grams per square meter to lawns and water thoroughly. Dolomite should not be used on acid-loving plants, including Azaleas, Camellias, Magnolias, and several Australian native species.

Blood and Bone

Blood and Bone is a fertilizer that also acts as a soil conditioner, improving drainage, aeration, and water retention. Nitrogen, Phosphorous, and Potassium are all present in their purest form. Before planting flowers and vegetables, spread 50 grams per meter. Fruit and citrus plants, flowers, and lawns all benefit from Blood & Bone. In August and March, apply 100 grams per square meter to lawns. After you've applied it, rake it in and water it in.


Natural gypsum is used to break up caked or crusted heavy clay soils, allowing for better drainage and aeration. It may be applied twice a year, and regular application will help to enhance the soil structure. Because gypsum is neither acid nor alkaline, it has no effect on the soil's natural PH.

In the summer and spring, gypsum can be applied on lawns. Apply 125 grams per square meter, rake in, and thoroughly water. The lawn may become yellow at first, but this will fade with proper watering and feeding. Use 1kg, which should be spread around a square meter to new garden beds and work into the soil before planting. The top 20 cm of your established plant beds can be covered with gypsum for proper plant growth.


Lime is a mineral found in nature and is used to sweeten acidic soils. It aids in the provision of calcium to plant roots, which is an important nutrient, as well as raising the pH and assisting in the release of nutrients held in acid soil.

When growing tomatoes, cauliflower or beans, or sweet peas, lime is an excellent choice. Before planting, work 125 grams per square meter into the soil. Spread 125 grams per square meter evenly on lawns and water thoroughly. If you're planting acid-loving plants like azaleas, rhododendrons, camellias, or magnolias, don't use lime. Some indigenous are also unsuitable for lime treatment.

Using a Soil Conditioner

It's recommended to start by testing the soil while establishing a bed for new plants. You may next prepare the beds by removing any debris once you've determined out what your soil could be lacking. Weeds, pebbles, or other undesired vegetation in the vicinity might be the source of this problem. Lightly till up the soil roughly 4 to 5 inches deep to make it easier to put the soil conditioner. Apply the soil conditioner to the tilled land and mix it in with the topsoil with a rake. Your soil is now ready to grow whatever plants you choose.


Compost is a medium-density mixture of decomposing nutrient-rich soil formed organically using oxygen, microorganisms, water, and organic components. To create compost, green stuff, such as food and grass clippings, is combined with brown matter, such as twigs and dried leaves. In the composting process, this mixture begins to degrade. The ingredients decompose, forming a rich soil that is mostly used to replenish depleted soils in the spring before planting again.

Types of Compost

If you're using pure compost to top-dress your lawn, strain it first so that it works best, incorporates into the soil more rapidly, and blends better with the topsoil of your house rather than resting on top of your beds.

Composted Manure - This is composted raw manure that generally contains some straw particles.

Green Waste - Garden trash and kitchen garbage are used to make composted green waste, which is generally created in a compost bin.

Sterilized Loam Compost - This is a mixture of sand, silt, and clay that has been treated to ensure that it contains no harmful chemicals or organisms. Loam usually includes a larger proportion of sand and silt than clay.

Wood Chippings – This pure organic compost is prepared from wood chippings and cuttings from trees that have been composted.

Before adding heavier media, thoroughly sieve your garden soil so that the compost can be a top-dress that makes its way deep into the veins, never to be heard from again. As you may know, compost is generated by decaying organic waste in a controlled setting. Animal manure, vegetable scraps, kitchen leftovers, and other waste created from organic sources are among the items used. Ready composts have a dark color, are lightweight, and are slightly humid due to the moisture content.

When compost is combined with soil, it behaves like a sponge, retaining water. It releases water when the plant's roots require it. Compost can also help to prevent disease transmission. It also supports the growth of beneficial bacteria by gradually releasing nutrients into the soil.

How to Use Compost?

For growing vegetables in the fall, add lots of compost to your food garden. In spring, use several inches of compost and work it into the soil.

When planting, add a handful of compost to each hole.

You may add a half-inch layer of compost around the base of the plants if they start to develop fast. Provide 1/2 inch of compost to "heavy feeder" plants like tomatoes, maize, and squash once a month for fantastic results.

When it comes to flowers, loosen the top few inches of annual and perennial beds and add a 1-inch layer of compost in the spring. Apply a 1-inch layer of compost as mulch to protect plant roots from freezing in the fall.

At the end of the day, it’s all about what your garden reacts to naturally. This is why it is advised to make a choice between these two options based on the results you get.

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