What is Potting Soil and How to Make a Good Potting Mix
Wondering which is the best soil to use for your terrace garden plants? We explain what potting soil is and how to make a good potting mix that will have you growing healthy plants.
Potting soil is that soil that you add to the pots for seeding or transplanting your plants. There are a number of potting mixes available in the market today, but they can be expensive and therefore not ideal for purchase. Plus, you never know what goes into those mixes and if they are indeed 100% organic as the label says.
Luckily you can make your own potting mix with ingredients most of which you can source yourself. After all, isn’t the whole point of home gardening aiming to be self sufficient?
In this post, we take a look at the key ingredients of a potting mix and how to make a good potting mix at home and enrich it.
Characteristics of a Good Potting Soil
Unlike garden soil, you have more control over the composition, structure and nutrients of potting soil. The best potting soil is one that is light and airy, allowing free space for the roots to grow while providing proper drainage.You’ll be surprised to know that the #1 killer of potted plants is water logging. A well-drained soil will ensure that the roots get the water they need while preventing water stagnation.
Another characteristic of a good potting soil is the ability to provide a continuous supply of different nutrients that plants need for growth. Since pots only hold a limited amount of soil, the nutrients that you supply initially get depleted quickly so you need to keep topping it up on a timely basis to maintain its quality.
Ingredients of a Good Potting Mix
Soil dug up from your garden can form part of your potting mix because it is something that is readily available. If you don’t have access to garden soil, you can buy them from a local nursery at very affordable rates. The best garden soil is loamy as it retains the right amount of water while allowing air circulation and easy root penetration.
Perlite is a whitish lightweight inorganic material that is formed from a type of volcanic glass heated at high temperatures. It is often used in agriculture for its ability to hold air and water and allow good drainage. You can use Perlite for seed starting as it is light enough to facilitate the sprouting of seeds and spread of the young roots. Perlite is available in many online stores. I picked up mine from Amazon.
This is another inorganic material that comprises mainly silica. Just like perlite it has a high water retention capacity while still offering good drainage to the soil. Bulbs and tubers are usually stored in dry vermiculite to prevent it from rotting.
Vermiculite is much superior to perlite and is used in seed starting as it retains water for longer periods. It also has much to offer to the plants by way of nutrition. If you find that your garden soil is too clayey, you can add vermiculite to increase drainage and air circulation.
This is the perfect replacement for perlite and vermiculite as it contains a some of the properties of both. River sand is wholly made of silica and allows good drainage but it cannot hold water or nutrients. It is still a good addition to any potting mix.
Compost is the plant and animal waste that is left to rot until it breaks down into dark matter with no stink. It is often referred to as black gold and is filled with full of beneficial microbes that keep the soil well balanced. Compost can be shop bought but it can also easily be made from your kitchen waste at home.
I’ll cover how to make your own compost at home later next week. When you use compost in your potting mix, make sure that it is aired well and any hard particles like bones or stones are removed.
Animal waste generated from farms that rear cattle, sheep, horses, chicken and goats make up this ingredient of potting soil. Fresh manure is usually harmful to plants so care must be taken to rot and age the manure before it is is used in potting mixes. You’ll know well rotten manure by the fact that is has a texture similar to compost with no stink or offensive smell.
Leaves from trees or plants that are crushed and partially composed are referred to as leaf mold. Although it decomposes very slowly, it can still be added to potting soil to add organic matter to it.
Peat moss is basically partially decomposed material found in swampy areas. It is capable of retaining water for extended periods but increases the acidity in the soil. It is best used with alkaline soils to amend the soil and make it neutral. If added to neutral garden soil, it must be used in combination with limestone to reduce the acidity.
Although coco peat adds no nutritional value to the soil, it is light, capable of water retention and completely organic and is a great medium to be used in pots. It is especially ideal as a seed starter soil. I pick up my stock of coco peat from Coco Garden on Amazon.
Limestone is a naturally occurring organic mineral that consists of calcium and magnesium. However, the main reason limestone is used in potting mixes is to reduce the acidity in the soil.
How to Make a Good Potting Mix – Potting Mix Recipes
Now that you know all the ingredients that can be used in a potting mix, the question is should you use all of them and if so in what proportion?
The answer is that you don’t have to use all the above mentioned ingredients in your potting soil. What you need is a good balance of organic and inorganic materials. You will also need to include 1 ingredient that offers good drainage to the soil.
Here is a look at some handy potting mixes you can make yourself:
Simple Potting Mix
- Garden Soil – 2 parts
- Compost – 1 part
- River sand or Perlite – 1 part
If your garden sand is too sandy you can add 1 part coco peat instead of river sand to help improve water retention. I use coco-peat instead of river sand when I make my potting mix.
Soil-less Potting Mix
If you don’t have garden soil or don’t want to use garden soil, you can still create an ideal potting mix with other ingredients. Here’s one recipe:
- Vermiculite – 1 part
- Coco peat – 1 part
- Compost – 1 part
- Bone meal – 2 Tbsp
Potting Mix for Succulents
Succulents needs a quick draining medium, otherwise it will rot. Here’s how to create a potting mix for succulents:
- Garden Soil and Compost – 1 part (equal parts soil and compost)
- Perlite – 1 part
- River sand – 1 part
How to Enrich Your Potting Mix
Now that you have a basic potting mix with compost, you should feel pleased that you have a soil that will take care of your plants’ nutritional needs. However, it never hurts to enrich your potting mix with some special fertilizers that release nutrients slowly on a long term basis. These organic fertilizers include items like fish meal and bone meal. Well aged manure is also a good addition to the soil.
Now that you have a basic idea about how to make a good potting mix, prepare a good one for your garden plants.