by Bethany Hayes
Soil is like the foundation of your house. If your soil isn’t good, the whole garden will eventually fall apart and crumble, so whether you practice in-ground gardening, raised bed gardening, or container gardening, you need to find the best soil options.
Yet, when you head to your local nursery, you’ll find tons of options. So how are you supposed to decide the best soil options for container gardening? There seem to be hundreds of different soil types at local stores, but not all work to grow veggies and herbs in containers.
Despite what you may think, dirt is not all equal, and if you want to give your plants the best foundation to thrive and grow, you have to understand the differences and the best soil, depending on what you want to grow.
Topsoil vs. Potting Soil: Is There a Difference?
When you’re at the store, you’ll find bags of topsoil and potting soil, but despite both containing the name “soil,” they aren’t the same.
Potting soil contains no soil at all, even though it has the name soil in it. Instead, it’s a mixture of ingredients designed to drain well while being aerated. Each blend of potting soil you buy is made with a unique blend created by that manufacturer, but most contain the same ingredients, such as vermiculite, sphagnum peat moss, coconut husks, and bark.
These components create an ideal texture for roots to grow while allowing moisture to move without getting too compacted and stuck together. Compacted soil doesn’t let oxygen get to the roots, and it’s an essential component for plant health.
Topsoil doesn’t have any unique ingredients. Instead, it’s the layer of dirt you might scrape away when pulling weeds or your kids dig in the backyard. Most consider it a filler, but you can mix it with sand, compost, manure, and other ingredients to create nutritious garden soil.
Topsoil should never be used by itself; consider it a filler or a soil conditioner rather than a planting medium.
Can I Use Garden Soil in Pots?
One of the most common mistakes new gardeners make is using garden soil in pots.
You might think that you can dig dirt out of your backyard and use it in your containers because it works for other plants, so why not pots? You might luck out and have no problems, but this is a risky thing to do.
First, garden soil has a lot of other contaminants in it; potting soil comes sterile to you. You might introduce diseases or bugs to your otherwise healthy plants, plus you also will introduce weed seeds to your pots.
Another problem with garden soil in containers is that it’s too heavy and dense to use. The dirt will end up compacted, preventing water and air from reaching the roots. It will cause your plants to struggle to grow and thrive.
How to Pick The Best Soil for Container Gardening
When starting a container garden, you want to make sure you use potting soil because it has the right texture and moisture retention for growing plants.
One of the challenges of container gardening is that potting soil cannot gain any more nutrients back from the earth. It’s outside of the ecological cycle, so you lose out on the benefits of the ecosystem. So, you have to make sure you provide your plants with all they need.
Another problem is that the roots can’t spread out as far as they might with in-ground gardening. When plants in the ground lose nutrients, they push their roots deeper in search of what they need. These plants in pots depend on us solely for survival.
You want to pick the best soil for container gardening!
So, let’s go through the steps to find the best container gardening soil.
- Read the Labels
You first have to look at the label and make sure the manufacturer didn’t create the soil for a specific plant. Some potting soils are for particular plants, such as orchids or azaleas, so you’ll only want to use those if you’re growing those plants.
- Check the Ingredients
Next, take a look at the ingredients and see the components of each potting soil blend. For example, you don’t want too much bark or sand in the mixture.
- Check the Consistency – If Possible
If you find a bag open, check the consistency before buying it. You want it to be light and fluffy with good drainage. Then, smell it – the scent should be pleasant, and you don’t want to find large chunks of bark in the mixture.
Here’s what to look for in container garden soil.
- It should be light and fluffy.
- It needs to be porous so that water can reach the roots.
- No bugs should be in the bags of soil. If you see bugs around the bags, don’t pick that one.
- The potting mix shouldn’t feel sandy or too coarse.
- It should be moist but not soggy and saturated.
- Make sure it doesn’t have a stinky or rotten smell.
- Think about Your Container
You also want to consider the container you’ll use for your plants. For example, some soil is heavier than others, and that matters if you have hanging baskets or planter boxes under your windows.
A general all-purpose potting soil mix is a great choice when you have large containers. These typically contain compost, so they work well for containers that sit on the ground.
If you have a hanging basket, the weight of the soil matters, especially when combined with water. A hanging basket or planter box becomes considerably heavier when saturated with water.
You want a soilless mix made of peat moss or coco coir as the base ingredient in these situations. Compost and sand are typically not in these mixes because they weigh more.
How to Fill Containers with Soil
Once you pick the best soil, it’s time to fill your containers with potting soil. The steps are easy, but make sure you follow them to fill containers correctly.
- Clean Your Pots
It’s always best to start with a clean pot. It’s safe to reuse containers from previous growing seasons, but you must remove all dirt. You should also clean the containers with a diluted bleach solution; diseases and other contaminants may stick to the inside of the containers.
Clean your pots even if they’re brand new! You never know what bacteria might be on them.
- Add Soil to the Bottom
Take some of the potting soil you selected and add it to the bottom of your container, gently packing it down. This helps ensure your plant will be at the proper depth when adding it to the container.
Your goal is to only have one inch between the soil and the top of the container once filled, so keep that in mind and use that to determine how much soil to add to the bottom.
- Place Your Plant & Fill
Now, hold the plant in your hand and put it into the pot, gently loosening the roots at the bottom. Then, fill in around the roots with the potting mix, packing the soil as you fill it. Make sure you keep the root ball planted at the same depth as it was in the original pot.
After your plant is in the container, water the soil deeply, letting it drain out the holes.
How to Make Potting Mix for Containers
Buying pre-bagged potting mix for containers gets pricey fast if you want to have several containers full of plants. One of the ways to save money when gardening is to make your own potting soil, and you can do so reasonably inexpensively compared to buying multiple bags of potting mix!
Here’s what you need.
1 Part Peat Moss
The first thing you need is one part of peat moss. Peat moss is light and airy, and it won’t compact like typical soil. So you add it to your mix to help retain moisture and increase drainage. However, since it’s hard to moisten, you need to soak the peat moss before adding the other ingredients to your homemade potting mix.
1 Part Compost
Peat moss doesn’t contain any nutrients, so you must add compost to the soil mixture. You also can use worm casting, but it’s more expensive than compost, which you can buy in bulk to save even more money.
1 Part Vermiculite
Then, you need one part vermiculite or perlite. The purpose of these components is to aerate the soil and create little pockets that expand and hold water. You don’t have to add both; most pick one or the other.
Perlite is different. If you’ve ever noticed small white rocks in your potting soil, that’s perlite. It prevents soil compaction, but it doesn’t hold water like vermiculite.
FAQs about Container Garden Soil
Here are some more questions you might have about filling your containers with soil. Remember, finding the best foundation for your container garden is vital for the survival of your plants.
Can I Reuse Soil for Containers?
It seems like a great idea to reuse soil for containers – it would save money -, but it’s not a great idea for two main reasons.
First, that soil is depleted of any nutrients. Container soil cannot replenish nutrients through its ecosystem like in-ground gardens. So, the soil in containers from last year is void of all the vitamins and minerals needed for plants to grow.
Second, you might contaminate that soil with diseases or pests. Some pests are microscopic or so small that you might not see them until they kill your plants.
Dump your used container potting soil into a compost bin and start with new soil every year. The exceptions to this are very large, deep containers and perennial plants. In these cases, remove the top several inches of soil and replace it with fresh soil.
Typically, it’s best to remove the potting mix around your perennial plants by the third or fourth year and start over with new soil.
Do I Need to Add Fertilizer to Container Potting Soil?
Container potting soil loses all of its nutrients faster than the soil you might have in raised garden beds. So not only do plants use up the nutrients as they grow and produce fruits, but some of the nutrients flush out of the bottom of the container whenever it’s watered.
So, you have to fertilize your container garden regularly. These plants rely on you to give them all the nutrients needed to survive.
Can You Add Manure to Containers?
Manure is safe to add to containers, but it must be well-composted. Fresh manure contains too much nitrogen and will burn your plants if used before composting.
Composted manure is safe to use in containers if mixed with other media to create a potting soil mix; it contains all sorts of nutrients your plants need to grow and thrive.
Why Can’t You Just Use Compost Only?
Compost is great, but you cannot use only compost in your container garden. You should mix it with other media because too much compost will compact your plant’s roots and have poor drainage.
Pick The Best Soil
Remember never to use regular garden soil or only topsoil in your containers. You need to use potting soil for container gardens to allow water to drain out and avoid soil compaction. If you can’t find a potting mix you like at the store, try making your own!