I had some soil conditioner I purchased at a discount. And wondered if I could use it as potting soil for my plants.

You cannot use soil conditioner as potting soil because it can create an over-rich base that can damage your plants. Soil that is too rich in nutrients can harm roots so they can’t uptake nutrients and water. Soil conditioners may have fine particles that don’t give stable support to plant’s roots.

In this post, I’ll help you understand why you can’t use soil conditioner as potting soil. I’ll also discuss the differences between potting soil, fertilizer, and soil conditioner. You can also make your own soil conditioner and use it on your plants.

Let’s take a look.

What is a soil conditioner?

Soil conditioner is a product used to improve the quality, physical properties and nutrient balance of the soil. Soil conditioners come in many forms, including liquids, granules and powders; the most common form is fine granule designed to be mixed into potting soil to optimize plant growth and health.

Soil conditioner improves aeration, hydration and oxygen penetration of the soil. The term ‘soil conditioner’ is used to refer to a subset of soil improving materials like fertilizers and compost.

The soil conditioner can help improve compacted soil that contains a lot of clay which has poor drainage and air circulation.

Soil conditioners can be organic or inorganic, and often contain ingredients like coffee grounds, blood and bone meal and garden gypsum.

Soil conditioner is much more beneficial to outdoor soil and ground, so it’s not going to have that much of a helpful impact on potted plants. The soil used for potted plants is different because it contains a unique combination of nutrients that regular soil doesn’t, and soil conditioner is not designed to help this type of soil. The whole purpose of soil conditioner is to improve the fertility of soil, and potting soil is designed to be much more fertile than any other type of outdoor soil. – Jeremy Yamaguchi, CEO of Lawn Love

Can I use soil conditioner as potting soil?

Soil conditioner should not be used as potting soil as it is too fine to allow the plant to establish firm roots and structure.

Potting soil is specifically designed for plants grown in pots, as it retains appropriate moisture, locks in nutrients and has been pasteurized to stop bad bacteria growth that can damage plants.

Potting soil is also made to stop soil from becoming compacted overtime, which can hinder growth and nutrient uptake for your plant.

When choosing a potting soil, choose something that is designed specifically for pots, as poor drainage can rot the roots of your plant and cause lasting damage.

What is the difference between a potting soil and a planting mix/soil conditioner?

Potting soil is a soil mix used for the bulk of a plant’s environment. This soil is used to retain moisture, for your plant to establish roots, and provide a base for growth. A potting soil/soil conditioner mix is soil with a soil amendment mixed through to increase water-holding capacity, aeration and nutrients.

Potting soil/soil conditioner mixes are better for encouraging plant health for young plants when first potted, particularly when used in addition to compost or fertilizer for nutrient release.

Can you grow plants in just soil conditioner?

You cannot grow plants in just soil conditioner because it does not provide a good foundation for the plants’ roots. The soil conditioner will contain lots of nutrients that may cause over-fertilization problems to the roots.

Soil conditioner is formulated to encourage a fertile ground for plants to thrive. They are not designed as potting soils, and so have a much finer texture that is made to be mixed through spoil to encourage water retention and nutrient uptake.

How to use soil conditioner?

Soil conditioner is used by mixing through the top few inches of the soil surrounding your plant. This changes the physical properties of the plant and allows it to hold more water, oxygen and nutrients.

Soil conditioner left on top of the soil can dry out and have the opposite effect by causing reducing hydration to shallow roots and the external structures of your plant.

Can I use soil conditioner as compost?

You cannot use soil conditioner as compost if it made of materials like bone meal, blood meal, coffee grounds, or manure. These are fertilizers and need to be added in limited quantity to the potting soil. You could use compost itself as a soil conditioner.

Compost typically has larger particles designed to retain moisture and encourage the growth of healthy bacteria in the soil. Soil conditioner has smaller particles that allow it to penetrate the soil and increase water-holding capacity, nutrient uptake and balance the soil’s pH for optimal plant growth.

For best results, use soil conditioner in additional to compost by mixing them with the potting soil.

What is the difference between soil conditioner vs. fertilizer vs. compost?

A broad range of materials have been described as “soil conditioner” because they help improve soil quality. Examples include biochar, bone meal, bloody meal, coffee grounds, compost, compost tea, coco coir, manure, straw, sphagnum moss, vermiculite, sulfur, lime, Hydro absorbent Polymer (HAP), biosolids.

How to make soil conditioner?

Soil conditioner is any product used to improve soil properties and optimize long-term plant growth. We can make soil conditioner of a combination of different materials depending on the soil type and requirements of your plants.

To make soil conditioner, mix one part composted manure, one part inorganic matter like gypsum, and three parts organic boosters like seaweed powder or blood and bone meal.

Test an area of your soil with your mixture and amend the ratios as required. We can buy soil conditioner ready-made from gardening centres and will usually contain a combination of organic and inorganic materials for the best results.

How much soil conditioner do I need?

The amount of soil conditioner needed depends on the type of plant you are growing and the type of soil you are using.

A general rule of thumb is to use between ½ cup to ¾ cup of soil conditioner per square foot of soil and mix it through thoroughly to see the best results on your soil’s pH levels and properties.

So, are soil conditioners worth it?

Soil conditioners can be a great way to improve the properties of poor-quality soils and create a beneficial environment for your plant to thrive in.

Ready-made soil conditioners can be purchased from garden centres, or you can make your own at home using easily purchased materials and scraps from your kitchen.

Not all soil conditioners are created equal–do your research to make sure that your soil conditioner is right for you and your plant.