If you’re thinking about making your own potting mix, one of the first things you’ll need to know is what ratio to mix the ingredients in. But how do you find out what that exact ratio is? And how do you know it’s going to be the best ratio for your plants?
While there is no perfect potting mix that will work for all plants, a good starting potting mix ratio has a 1:1:1 ratio of ingredients that provide moisture retention, drainage, and nutrients. Depending on your specific plant’s needs, you can adjust the proportions to meet those needs accordingly.
Let’s get into how you can start from your baseline potting mix ratio and find out how to adjust it to get closer to a perfect ratio for your plants.
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How Do You Make the Perfect Potting Mix?
Let me set one thing straight: there is no perfect potting mix that works for all plants in all scenarios. Although, there are certainly really good ones that will work for most plants.
There are thousands of different potting mix recipes you can find online, most of which are probably at the very least good enough as a starting point. There’s a wide variety of acceptable potting mixes.
You can even start with a simple, but effective 1:1:1 ratio of peat moss, perlite, and compost.
Most potting mix ratios hover around a roughly equal balance of ingredients providing moisture retention, drainage/aeration, and nutrients. As long as your potting mix has those three qualities, you should be good to go.
But that being said, there is a way to make a potting mix that is perfect for your specific plant. And there’s a way to make it with the right ingredients and at the perfect ratio.
To make the perfect potting mix for your plant, you will have to go through several iterations to find out what your plants best respond to starting with a solid baseline.
As your plant grows over time and goes through multiple seasons of growing and repotting, you’ll start to get a better idea of what type of soil your plant responds well to (or doesn’t respond so well to). You’ll also start to find out what type of soil you personally prefer to work with based on your watering habits.
It’s through these observations that you’ll be able to find out the next iteration you should try the next time you repot your plant or get a new one. If you like, you can keep a journal to have a record of what you’ve tried before and how your plants responded.
How Do You Increase the Quality of Your Potting Mix?
There are three main variables that you can control in your potting mix that will affect the quality:
- Moisture retention
Let’s get into when, how, and why you would want to increase or decrease each one of those variables in your potting mix.
This is a measure of how well your soil holds on to moisture and how slowly it dries out.
Generally speaking, more moisture retention is better, unless you have plants that come from an arid environment like succulents or cacti.
Most of the moisture retention comes from your base materials. Most recipes use either coco coir or peat moss.
If you’re finding that your soil dries out very quickly, you can try switching to coco coir, which can hold up to 20 times its weight in water.
You can also increase the ratio of your base material to improve the water retention if you’re using a recipe that’s already high in ingredients that increase the drainage.
This is a measure of how well water drains out of your soil and how many air pockets (oxygen) are in the soil. Your plant needs oxygen to perform respiration.
It might sound like the opposite of moisture retention, but it mainly takes effect when the soil is oversaturated with water.
The most common ingredients that increase the drainage include:
- Orchid Bark
If you find that you like to water your plants often or your plant prefers well-draining soil, it can be good to add more ingredients that improve the drainage. This will help protect your plant from overwatering.
It’s worth considering improving the drainage if you’ve found that some of your plants have been overwatered.
You can also add these drainage components if you find that your soil tends to compact after it dries up. If your soil compacts, it can become hydrophobic and prevent water from actually reaching your plant roots.
Drainage ingredients can make it more difficult for the soil to compact and keep your soil light and airy.
Plants need nutrition to support growth and development. The main soil nutrients are nitrogen (N), phosphorus (P), and potassium (K).
It is especially important when your plant is in the growing season because your plant will need a lot of nutrients to support new growth.
Nutritious ingredients include:
- Worm castings
- Fertilizer (added only during the growing season)
If you find that your plants aren’t growing as fast as you were expecting, the nutrition content might be a good place to start looking. Adding fertlizer is one way to help your plant grow, but it’s not a requirement if your potting mix has nutrients included.
The nutrient content in your soil can also decrease over time as the nutrients are washed out over repeated waterings. It’s important to either replenish the nutrients with fertilizers or, better yet, replace the soil with a fresh batch the next time you repot your plant.
Having too many nutrients or too many of one nutrient can be detrimental for your plant’s health. If an excessive amount is coming from just one or two ingredients, it can cause an imbalance of certain nutrients over others, inhibiting your plant’s uptake of other nutrients.
How do you make pest-free potting mix?
On a related note, it’s worthwhile to quickly cover how to make your potting mix pest-free.
There are a number of ways to prevent pests from inhabiting your soil, but there are ways to kickstart the prevention as soon as you start making your potting mix.
To improve the pest-resistance of your mix, you can mix in some diatomaceous earth and neem oil. These are natural pesticides that will make your soil more hostile for any unwanted guests while being perfectly safe for humans and pets.
It’s also a good idea to sterilize your soil before using it to ensure you’re not starting out with an infested potting mix. To do this, you can either bake your soil for about 30 minutes at 180-200 F or spray it down with a hydrogen peroxide solution.
If you want to read more about that, you can read my other article, How To Make A Pest-Free Potting Mix At Home
Hope this helps!