Most gardeners soon learn that you can’t simply fill containers with standard dirt or garden soil and expect plants to thrive in them. You need a potting mix, which is often coarser in texture than typical garden soil and best used in container gardening. Read on to learn why you should make your own potting mix, as well as which nutrients to add for various species.
6 Reasons to Make Your Own Potting Mix
Ask any do-it-yourselfer and you’ll discover that there are many reasons why people like to take care of things themselves. Sure, you can buy a large bag of mix at your local superstore, but learning to make your own has numerous benefits for any garden. This is especially true for heavy-feeding container plants that will require fertilizers throughout the growing season.
Here are the top 6 why making your own potting mix is always a good idea:
1. You Can Create the Soil You Need
Standard garden soil is dense and heavy. Too heavy, in fact, for plants in containers to thrive in. The dirt will become compacted into the container over time, which can prevent plants from growing properly, or the roots from spreading out easily.
The lighter the mix, the better. Loose mixtures allow water, fertilizer, and air to reach the plant’s roots easily while providing proper drainage.
2. You Know Exactly What’s Inside Your Soil
The fact that you’re making this yourself means that you know exactly which ingredients are going into it. This allows you to ensure that your mix is entirely organic. Some store-bought mixes contain soil wetters, hazardous chemical fertilizers, or water crystals that use chemical polymers. These can be dangerous, and are really important to avoid for your overall health.
If you think I’m paranoid, think again! Gardening Australia ran potting mix tests to see if the fancy labels actually showed what was in bags of mix they sold, and the results even surprised garden experts. The truth is that with bagged mixes, you really don’t know what you’re getting until you try it out on your plant. Is convenience really worth the risk?
3. Save Your Hard-Earned Money
Buying huge bags of mix from your local gardening center is costly. In addition, if you have quite a large container garden, this may quickly become too expensive. Making your own mix, no matter which nutrients you decide to add, is always cheaper than purchasing a pre-made mix from the store.
Bagged mixes range in prices and quality, with the premium options boasting the highest price tags. You can whip up a large batch of your own premium mix at home and save the leftovers for future use.
4. Homemade Mixes Last Longer
With the right ingredients, each recipe you whip up will last longer than a bagged mix. Not only will it last longer, but containers won’t need fertilizing or repotting as frequently because they have more of the nutrients they need in the mix.
This also works because many bagged mixes contain higher levels of bark, which help retain moisture but also decompose very quickly. You’re aiming for good water retention, but not too much.
5. Self-Reliance Feels Great
Making your own gardening supplies and watching your container garden thrive as as a result is an insanely rewarding experience. Plus, you can share the skills you learn with other people.
6. You Can Modify the Mix to Suit Different Plants
The best part about making your own mix is that you can set your plants up for success easily and quickly by modifying the nutrients you use. Different plants have different needs in terms of pH levels, nutrients, and water retention, especially when grown in containers. As such, you can easily add ingredients to the recipe for each potted plant, and save the rest to use later.
The Best Additives For Various Plants
Some crops are greedy and require a high amount of nutrients in the soil, especially in container gardening. The potting mix you choose must be rich enough to provide the nutrients the plants need to live for a decent period of time.
Alter the nutrients in your potting mix for specific plants as needed for each species. This allows you to learn what works best for the various plants you’re cultivating. Customize the nutrients to fit each plant and you’ll see your container veggies and plants begin prosper in no time.
Nightshade vegetables like peppers and tomatoes are two varieties that need specific nutrients added to their soil for the best results. A mix with three parts compost to one part leaf mold, loam, or coir is idea. Add a bit of liquid fertilizer when needed to help these plants thrive while their fruits mature.
A Few Specific Soil Types:
If you need a fast-draining mix, for example, use coarse sand or perlite in your mix to allow the water to flow freely. Add worm castings or well-rotted manure for a richer soil, and vermiculite or peat to help add moisture retention.
Cacti, lavender, and succulents require rapid drainage, while woodland flowers such as primrose or ferns need moisture retention.
You can also adjust the pH balance to suit a variety of plants by using either soil sulfur to lower the balance or lime to raise it. Both of these additives are available at your local garden center. Check the soil’s acidity level, altering the mix as needed.
Lettuce, marigolds, and Russian sage, for example, do well with sweeter soil, with a pH of 7.5. Acid-loving plants such as asters, ferns, and strawberries will enjoy a pH of around 5.5-6.
A guide on soil pH level preferences for various types of plants will help you determine what the pH balance of your soil should be, depending on the plants inside each of your containers.
How to Make the Best Homemade Potting Mix
Contrary to what you may think, the best potting mix doesn’t contain any soil or dirt. It’s actually a blend composed of:
- Peat moss or coconut coir – Use these as the base ingredients, as both work well for aeration, water retention, and nutrient suspension. Peat moss, however, is less sustainable and more acidic than coir.
- Vermiculite – A natural ingredient, vermiculite aid water retention and keeps the soil fluffy.
- Perlite – Prevents soil from compacting and helps produce a well-draining mix.
- Sand – Allows better water drainage and traction in the mix.
- Shredded bark or Compost – Container plants need lots of nutrients, and compost is an easy and natural way to boost your soil. Bark aids water retention.
It’s important to protect your health when working with potting mixes and soils. Legionnaire’s Disease is a serious danger that can be contracted from bacteria living in potting mixes and compost, and this severe form of pneumonia requires a few safety precautions.
First, always wear a face mask, protective clothing, and gloves. Avoid inhaling organic particles or getting dust from the mix in your eyes, and never work with the mix when the wind is heavy. Use a spray bottle to lightly mist dusty ingredients to keep them from flying through the air.
After working with your mix or around your garden, wash your hands immediately. If you ever feel ill and think it could be Legionnaire’s disease, seek immediate treatment from a medical professional.
Collect the following:
- Large bucket for mixing
- Measuring container
- Hose/watering can
- Protective wear (face mask, gloves)
Begin with your basic container plant mix and add in the nutrients your specific plant needs for ideal results. You should end up with enough mix for two 14-inch pots, or five 12-inch hanging baskets. Double the recipe for larger containers or to store the mix for future use.
To start, mix together the following ingredients for your basic recipe base:
- 10 quarts peat moss
- 5 quarts vermiculite
- 4-5 quarts perlite
- 5 quarts compost
- 2 cups time-release fertilizer
- 2 cups fine sand
- 1/2 cup lime
You can then add in specific nutrients based on the plants in your containers, or taking your local climate into consideration. Tweak the recipe to suit your plants, and always check the acidity. Levels between 6-7 work for most potted plants. Store the rest in a container with a secure lid to lock in moisture.
How Much Potting Mix Do You Need?
Soil and potting mix are often sold in large volumes at your local garden center, but when making your own mix, you need to know how much to expect each time you whip up a batch. Mixes are typically measured in quarts while containers are measured based on their diameter. Use the following as a key to help you know how much soil each sized pot will need, based on the type of container.
- 8-inch diameter pot = 3 quarts soil
- 10-inch diameter pot = 6 quarts soil
- 12-inch diameter pot = 8 quarts soil
- 14-inch diameter pot = 12 quarts soil
- 16-inch diameter pot = 20 quarts soil
- 20-inch diameter pot = 24 quarts soil
- 24-inch diameter pot = 28 quarts soil
- 30-inch diameter pot = 72 quarts soil
- 12-inch diameter basket = 6 quarts soil
- 16-inch diameter basket = 10 quarts soil
- 24 x 6-inch box = 12 quarts soil
- 36 x 6-inch box = 20 quarts soil