What Plant Containers Are Best For Container Gardens?
Not sure what type of containers to use in your container garden this season? There are many choices to choose from, so it can be difficult to pick if you don't know where to start. In this article, Certified Master Gardener Laura Elsner shares everything you need to know about picking the right containers for your container garden this season.
If you want to grow an incredible container garden, you need to start with a solid foundation. Choosing plants is easy, but you may get flustered trying to find the perfect plant containers. From fabric grow bags to metal troughs to hanging baskets to terra cotta pots, the possibilities seem endless! Plus, there are many urban legends about certain planters:
- Are grow bags worth the hype?
- Do terra cotta pots mold?
- Does galvanized metal leach heavy metals?
- Are large pots bad for indoor plants?
We’ve got all these answers and more. The three most important things to consider when choosing a pot include:
- Material: What is the planter made of?
- Size: How large your container is in relation to the plant
- Aesthetic: How a pot will look in your house or garden
Let’s break down each factor to help you choose your perfect container for any plant.
Planters can be made of nearly anything from plastic to terracotta to metal. You shouldn’t choose a container based on aesthetics alone. Certain pots are ideal for specific plants, for example:
- Best for Longevity: Metal or fiberglass
- Best for Raised Beds: Metal or wood
- Best for Cacti, Succulents, and Mediterranean Plants: Terracotta
- Most Portable for Moving Plants: Fabric grow bags
- Best for Cold Climates (Freeze/Thaw Cycles): Wood or fiberglass
- Best for Hot Climates: Wood, fabric, terracotta, or plastic
- Best for Tropical Plants: Ceramic
- Best for Hanging Baskets: Plastic
- Least Breakable: Metal, fabric, fiberglass, or plastic
The composition of a container affects soil moisture, drainage, and aeration. It is also very important to consider how a pot will react to certain weather conditions. Let’s dig into the pros and cons of the most popular plant containers:
Repurposed cattle troughs and steel planters grace the patios of every trendy restaurant for a good reason! Metal planters have a range of benefits:
- Perfect for raised beds: Galvanized steel is the superior material for raised gardens because it lasts for 5-10+ years, doesn’t crack, and naturally withstands all weather conditions. Most metal garden beds (like my favorite, Birdies) have a non-toxic powder-coated finish that protects from rust and adds a beautiful accent to the garden.
- Non-toxic: Unlike plastic or treated wood, there is no risk of metal leaching chemicals into your garden soil.
- Weather-proof: Metal can clearly withstand extreme weather far better than wood. Properly preserved metal planters (like galvanized steel or aluminum) are completely resistant to rust and corrosion.
- Easy to clean: Just like the metal pots in your kitchen, a metal garden pot is easy to clean and sanitize.
- Non-breakable: No risk of shattering a metal pot!
The main concern people have with metal pots is the potential to leach heavy metals into the soil. In reality, quality steel raised beds or pots are safely galvanized and sealed with food-safe paint to prevent leaching risks. Steel pots can protect your soil from compounds leaching from plastic or painted wood.
A common concern is that metal can heat up quickly in the sun. Here, this is both a benefit and a downside! This is a benefit for raised beds; the soil keeps the metal from being too warm by acting as an insulator, and raised beds warm up earlier in the season and can extend your growing time. But for a very small pot, like a decorative 4″ pail-shaped aluminum pot, there’s not enough soil to act as an insulator, and it can quickly get too hot for your plant’s roots.
Wood is probably the oldest type of planter in the world. While it is mostly used for raised beds, a wooden container can also function as a small windowsill planter or a stand-alone perennial pot.
The pros of wooden planters include:
- Natural material: From tree to mill to your garden, wood is the most natural planter material you can find.
- Widely available: You can find wooden pots and raised beds at nearly any garden store. You can also build your own wood containers with lumber or hollowed-out logs.
- Temperature regulation: Wood doesn’t get super cold or super hot. It is great for scorching summer climates where you are worried about the sun baking your plants.
The downside to wood is, of course, weather and water. Wood naturally rots. In addition, many avoid wood treated with chemicals or toxic paints. As a result, preservation becomes a problem. Some wood species, like cedar or redwood, are more rot-resistant than others.
Some people use an oil such as linseed oil (derived from flax) to provide a little exterior protection from the elements. However, this needs to be applied regularly and won’t protect the interior where moist soil is in constant contact with the wood.
Wooden planters also require saws, hardware, and/or glue to assemble. If you aren’t handy, you may want to opt for a metal, fiberglass, or clay pot.
For long-lived perennials or continuously planted garden beds, fiberglass is one of the best materials for both indoor and outdoor use. It is lightweight and comes in several shapes, sizes, and colors. This manmade material is a blend of resins and flexible fibers.
It doesn’t crack in cold weather or fade in the sun. Fiberglass can even mimic other materials like stone or terracotta, but it is more durable.
Other benefits of fiberglass plant containers include:
- Rust-proof: Fiberglass ages like fine wine, except it doesn’t fall victim to mold or rust! These pots will not degrade in the elements like terracotta or clay might.
- Frost resistant: No matter how many times it freezes and thaws, fiberglass pots can withstand the test of extreme winters.
- Shatter-proof: Fiberglass is ideal for high-traffic areas because the pots won’t crack or shatter if you accidentally run into them or drop them.
The main downside to fiberglass is that it heats up quite a bit in the sun. These containers are not great for hot southern climates.
It also costs more. However, these pots are built to last. If you invest in a fiberglass pot, you could have it for decades.
Terracotta is a classic container material. It’s a porous material that water absorbs into. This means you must water your plants more often since they will dry out quicker than other, non-porous materials. This is a bonus if you tend to overwater your plants or are growing Mediterranean herbs like lavender and rosemary.
Other benefits of terracotta include:
- Prevents root rot: The breathable nature of the earthen clay makes it more difficult for root pathogens to take hold.
- Great for wet climates: In areas with extreme humidity or high rainfall, terracotta ensures that outdoor potted plants won’t become waterlogged.
- Great for dry climates: Coincidentally, terracotta also works great in dry climates because it absorbs excess moisture and slowly wicks it into the soil zone, creating a slightly more humid area around the plant roots.
- Won’t topple over: Compared to plastic or fiberglass, terracotta pots are more bottom-heavy and less likely to fall over.
Unfortunately, terracotta pots can be prone to mold and mildew if you don’t clean them regularly. After all, this is a natural earthen material that will succumb to weather over time. A simple mix of hydrogen peroxide and water can be used to remove mold from clay pots.
Terracotta also has problems in frigid climates. It does not freeze and thaw very well. This material is prone to crumbling and cracking. It’s less durable for outdoor use. But terracotta is inexpensive and widely available. Make sure to get the matching saucer to catch excess water.
Fabric (Grow Bags)
Fabric pots are a cheap and lightweight option ideal for small-space container gardens or plants that need to be moved indoors during the winter. Fabric may seem like a strange material for a planter, but these woven pots are perfect for both ornamental and edible plants.
The benefits of fabric grow bags include:
- Portability: Fabric is, by far, the most lightweight pot material. Most grow bags come with handles for easy movement.
- Drainage: Fabric absorbs and wicks water away from the soil to prevent overwatering or root rot.
- Breathability: Most grow bag blends are made of woven synthetic fibers or natural burlap that allows the root zone to breathe. There are thousands of tiny holes between the fibers that allow air to flow through the soil.
- Washable: Fabric pots are easy to hose down or toss in the laundry before or after use. This prevents the spread of plant disease and keeps your container garden looking nice.
- Storage: No need to stack dirty pots in your garage! You can fold or roll up grow bags to store when they’re not in use.
- Durability: Compared to every other pot on this list, fabric grow bags are the least breakable. This makes them suitable for gardening with children or in areas with wild weather.
The only downside to grow bags is their tendency to rip if overburdened. This material does not work as well for extra large or heavy plants. Stitches can only be sewn so strong!
It should also be noted that if you plan on moving your grow bags indoors, you’ll need to provide a shallow tray to catch any runoff moisture from watering.
Ceramic pots are a classic choice. They are glazed and can have beautiful colors and details in them. These sturdy pieces of pottery dual-function as works of art in your home or garden.
Ceramic plant containers are great for tropical houseplants that enjoy moist soil. Other benefits include:
- Even heat transfer: The sealed clay of a ceramic pot holds onto warmth and helps regulate the soil temperature through the night. During the day, this material doesn’t heat up as quickly as metal or terracotta.
- Easy to clean: The smooth surface of a ceramic pot is easy to wipe or hose down.
- Less risk of mold: Unlike earthen terracotta pots, ceramic pots are sealed with a glaze that prevents mold growth.
- No deforming: Ceramic holds its shape and won’t warp like a plastic pot.
- Holds moisture: For tropical plants that enjoy moist soil, ceramic containers hold onto moisture. These pots are not breathable like terracotta or fabric. However, this is not ideal for plants prone to root rot.
The downside? Ceramic pots can crack and split if they freeze and thaw too much. They also can be very heavy and fragile.
Plastic often gets a bad rep, but these pots excel in affordability and durability. I’m not talking about plastic nursery pots, although you can use those too. Plastic containers come in a lot of different sizes, shapes, and colors. They also can mimic many other materials, like stone or terracotta.
The benefits of plastic pots include:
- Cheap and disposable: If you want to start a garden on a shoestring budget, plastic pots are the way to go! You can often find them for free from your local farm or nursery.
- Easy to clean: You can spray, scrub, or hose down plastic containers anytime during the season. Commercial growers use these because they are easily sanitized to prevent plant disease transfer.
- Shatter-proof: Plastic pots are ideal for a kid-friendly garden because they won’t shatter when dropped. however, they can crack.
- Great for hanging baskets: Plastic is ideal for hanging planters if you want to grow vertically, as it’s lightweight and resilient.
The main drawback of plastic is its potential to leach chemicals like BPA into your soil. If you are using plastic pots outside, they are also prone to fading in the sun. They also can crack and chip in areas with cold winters or after years of hot summers.
The ideal size of your plant containers will differ depending on whether it’s for houseplants or outdoor plants.
- In general, larger pots (5 gallons and up) are best for outdoor plants.
- Smaller pots (4 gallons or smaller) are ideal for indoor plants.
It would be best to opt for larger pots for outdoor plants whenever possible.
The main reason is water. Outdoor plants tend to dry out more quickly. A small pot might have to be watered multiple times a day in the heat of the summer. In contrast, the soil in a large pot absorbs more water and stays moist longer.
Another reason is overwintering. If you plan on overwintering plants outdoors in pots, larger pots work better as they are less susceptible to constant freeze/thaw than a small pot. Science shows that a large pot can better regulate soil temperature.
Indoor plants tend to do best in smaller pots, most specifically pots that fit the size of the root ball. You only want to go about 3-4″ larger than the diameter of the plant’s current pot.
This might seem counterintuitive since a plant grown in its native conditions would have unlimited soil space. But in a closed system like a container, too much soil will lead to less water absorption. This will create ideal conditions for harmful bacteria that cause root rot to thrive.
If you plant an indoor plant in an oversized container, be very mindful of watering. Excess water won’t drain out the bottom as easily. Instead, it will get absorbed by the extra soil. This can be especially problematic with succulents.
If you want a large pot for an element of design, I suggest using a liner so you’re not using as much soil. Alternatively, keep the plant in its nursery pot and place it in a decorative container. Never let your container sit in a pool of water if you’re using a decorative container!
Design is a matter of personal preference, so you should always lean toward a container you love. Here is some of my advice in terms of container design.
There are two different angles when it comes to plants and containers:
- Do you want to showcase the pot with a plant accent?
- Or are plants the focal points, and the pot is the accent?
If you choose a really intricate container, you might want a simple plant to highlight the container. A simple majesty palm might look great with a beautiful ceramic container full of swirls and details.
Another example of an intricate container is a head planter. These are very popular; the plant acts as the ‘hair’ growing from the pot.
On the other hand, if you select an intricate plant, you may want to keep the container design simple. This includes flowering plants like hoyas and African violets. It also includes plants with exotic foliage like coleus or begonias. A simple pot in a solid color adds a minimalist, classic accent.
For outdoor containers, consider your surroundings as well as your plants. I love when outdoor planters in front of the house match the door or the accent pillows on the patio furniture. You can also choose neutral pots and let the colorful flowers shine.
An important technical consideration is height. Tall containers can be stunning garden accents but aren’t suited for all plants. If you plant a tall plant in a short pot, it might be top-heavy and topple over. A tall container with short plants will look out of balance. Ideally, choose taller plants for larger, deeper containers.
No matter your container’s size, shape, or material, you need drainage! I can’t stress this enough. Piling rocks on the bottom is not considered drainage. Large drainage holes are ideal for draining excess water. If your pot is for a houseplant, purchase a bottom saucer tray for excess water to drain into.
If your container lacks a drainage hole, you can drill one into it. Use a ceramic drill bit for terracotta and ceramic pots. Some garden centers will do this for you. Optionally, you can also use a liner. Leave your plant in its nursery container, and then you can pour out excess water as needed.
Choosing your container is just as important as selecting the plant itself. It needs to be functional as well as beautiful. Consider all the pros and cons of each container before purchasing one. Take your time to decide.