Soil, dirt, Earth, or whatever you happen to call it, is one of the most critical components of the garden no matter what kind of gardening you do (except for hydroponic growing in soil-less media, but that’s another story). We may not often think about it, but that stuff we walk on every day is alive! Soil is a complex substrate of organic matter, minerals, water, fungi, bacteria, and other microscopic creatures, and is the backbone on which everything on Earth grows.
When it comes to gardening, you don’t need a scientific level of understanding to appreciate the value of good dirt. The logic is actually quite simple: Healthy soil grows lush, green plants that are bountiful in their food and flower production. Poor soil can give you a supply of headaches and frustrations as your plants fail to thrive and produce to their true potential. You’ll need all the luck you can get. Rich, healthy soil provides plants with many of the nutrients they need, and help plants to defend themselves against pests and diseases. This leads to more time for you to enjoy your garden and less time expended on hard work toiling in it.
The Ideal Garden Soil
When it comes to growing fruit and veggies, traditional gardeners aim for a soil that is rich in organic matter and nutrients, with a crumbly, loamy texture. The ideal soil retains moisture yet drains easily, and has a pH somewhere around neutral. This is important since most vegetables won’t grow in anything that is extremely acidic or alkaline, with a few exceptions. For example, blueberries like acidic soil with a pH somewhere between 4-5 (for reference, neutral pH is 7 on a scale from 0-14, with acidic falling on the low end and basic/alkaline falling at the high end of the scale).
You can measure the pH of your soil with a pH Soil Meter, which you can find online or at most garden centers.
On the other hand, poor soil can take on many forms, from compacted, wet, and hard to thin, dry, and dusty. Drainage in poor soil is often an issue, with water either draining too freely (such as with very sandy soil) or poorly (such as with clay-based soil).
The Ideal Container Soil
However, there are some extra criteria for container soils, and what works in an in-ground garden can be a very poor choice in a pot. When choosing a soil mix for container gardening, stick to potting mixes and stay away from bags labelled purely as garden soil, topsoil, or compost. These are normally quite heavy, and will become compacted in pots, slowly suffocating your plant and causing root rot from all of the retained moisture. Potting or container mix is a combination of several things that form a soil-like substitute designed to do three important things: hold moisture, drain freely, and let air into the soil to allow your plants’ roots to breathe.
The bad news is that bags of commercial mixes can vary widely in quality and price. A good potting mix will be made up of at least three major components:
- Organic Matter: such as compost or worm castings to provide nutrients.
- Perlite, Vermiculite or Sand: to aid in drainage, prevent compaction, and increase air flow.
- Peat Moss or Coir: to retain moisture.
In addition, some potting mixes may contain some form of fertilizer as well. This could be inorganic fertilizers, or something such as seaweed, manure or mushroom compost in its place.
Making Your Own Potting Soil
An alternative to buying bagged mix is to make your own potting soil. It may seem like a daunting task, but preparing your own mixes is quite simple as long as you have the space to store all of the ingredients. An added plus: it can actually save you money in the long run! However, this may not be ideal for many urban or small space gardeners who don’t have ample storage space. We live in a small one-bedroom apartment with nowhere to keep piles of “dirt”, so sometimes you’re forced to bite the bullet and buy pre-made potting soil when you need it. But if you’re insistent on mixing your own, we suggest buying smaller bags of the individual ingredients, mix your soil, and keep it stored in a sealable bin wherever you have space.
For container gardening, all you really need are two basic mixes:
Basic Seed-Starting Mix
That’s it! Seedlings don’t need an outside source of nutrients in the beginning, because everything they need is stored in the seed. You can add a bit of sterilized compost once the seedlings have produced their first set of true leaves, or start feeding with a half-strength liquid fertilizer at that time.
Basic Potting Soil Mix
You can amend this mix quite easily for plants with more specific needs. For example, you can add more sand for succulents or cacti that require better drainage and less soil nutrients, or add sulfur or an acidic fertilizer for growing blueberries.