The benefits to creating your own organic potting mix are numerous, but perhaps most notable of all is the fact that making your own mixtures allows you to control the ingredients and proportions that make up the soil. As a result, you will be able to customize the potting mix to your specific plant needs, enabling your garden to flourish.
When creating your potting mixes, ensure all of the ingredients are mixed together thoroughly to create the best possible outcome. Every type of plant requires a different potting mixture and this mixture varies at different growth stages. Before you begin creating your own organic potting mixture, ensure you know exactly what your plants need by way of air flow, nutrition, drainage and support. A good potting mix should do a variety of things, which varies from plant to plant, but generally, all potting mixes should:
- Hold nutrients well
- Be free of pesticides, pathogens and anything else that may be harmful to plants
- Be dense enough to support the plant
- Allow for air flow and drainage
- Retain enough moisture to feed the plant
The majority of preferred organic potting mixtures share common ingredients, but the amounts of each ingredient varies depending on the growing conditions your plants prefer. The following is a rundown on some of the main potting mix ingredients and the roles they play in caring for your plants.
Adding soil to your potting mixture is a great way to add density, but you must be careful what soil you choose as soil can contain pesticides or other diseases that may be harmful to your plants. If you’re using garden soil, sterilize it before adding it to your mixture. To do this, spread it over a cookie tray and bake for 200ºF for 20 minutes, stirring periodically throughout.
Compost is full of beneficial microbes and has a great water-holding capacity and nutritional content, making it a great addition to any potting mix. You can buy compost from your local garden center or nursery, or you can use home-made compost. If you use the latter option, be sure to check your compost is fully broken down into uniform, small-particle-sized pieces, which can take several months.
Sand is one of the best ingredients for adding ample physical support to potting mixes and it also helps provide air and drainage space. Not all varieties of sand work the same. Coarse blends of sand work best, especially builder’s sand, while fine and plaster sands are best avoided as they create an overly dense mixture.
Bone meal, a mixture of finely and coarsely ground animal bones, is a great addition to potting mixes where the intended plants will require a lot of phosphorous. The substance breaks down in soil over a long period of time, bringing plants long-lasting benefits. It’s especially kind to seedlings and is a popular addition among rose gardeners.
Due to its coarseness, the addition of gravel to potting mixes serves to improve water drainage. Pea gravel is most commonly used, but harder, larger gravels can also be used, yet they tend to lack water-absorbing pores, meaning water can drain away too quickly.
Agricultural lime, also known as garden lime, is a form of pulverised limestone or chalk. It acts as a fantastic neutralizing agent for acidic soils and soilless potting mixtures such as peat moss.
Bark helps lighten up potting mixtures by increasing pore sizes, allowing air and water to flow more freely. It degrades slowly, creating a firmer mixture. As it breaks down it may rob the potting mix of nitrogen so the addition of a nitrogen-based fertilizer may be necessary from time to time.
Perlite is a type of lightweight volcanic rock that is completely sterile and pH-neutral. Its addition to potting mixtures helps improve water drainage and increase airflow, making it a lightweight alternative to sand. Be careful not to add too much, or it will float during waterings.
As it is widely available and somewhat inexpensive, peat moss tends to be a main ingredient in soilless mixtures. It is a great addition to potting mixtures as it decomposes slowly and has a good water retention rate. On the downside, it tends to be highly acidic. The addition of lime can easily balance pH levels, however.
Vermiculite is a mined mineral that helps increase the porosity of potting mixtures. It also increases the water-holding capacity of the mix and adds calcium and magnesium. It must be handled gently, as a rough touch will cause it to compact and lose its porosity. When choosing a type of vermiculite for your potting mixture, coarse grade is best for older plants and medium grade is best for seedlings.
Coco coir is a by-product of the coconut fiber industry. It looks and acts similar to sphagnum peat, but is granular. Typically, coco coir is packaged in a compressed, brick-like form that will expand with the addition of water.
Along with your ingredients, you’ll need a few basic materials and tools to help you create your organic potting mix. First, you’ll need a container to help you measure your ingredients. This can be any size you desire, depending on how much mix you’re making.
Second, you’ll need a large bucket to mix your ingredients in. You’ll also need a small fork or trowel for mixing, access to water (a hose and watering can is ideal) and a container for wetting the coir peat and any other ingredients that may require pre-soaking.
Organic Benefits of Creating Your Own Potting Mix
Not only will creating your own potting mix allow you to ensure your plants get the exact nourishment they need, it will also allow you to reap the benefits of organic gardening.
By choosing organic ingredients you ensure your plants aren’t treated with potentially harmful synthetic materials and chemicals and that they grow in balance with nature.
In the case of fruits and vegetables, the organically grown varieties will be bursting with far more nourishment and taste than the store-bought equivalent.
As you can see, there are lots of reasons to go organic and DIY, so why not roll up your sleeves and get mixing?