If you hunt around on the Internet you will see an endless selection of plant pots, and also many things used as plant pots that were originally intended for other purposes. I have seen boots and pairs of jeans with plants growing out of them. Kitchen crockery, dolls, toys, wheelbarrows, kokodama (which is essentially string binding the root ball), and even entire vehicles used as planters.
As wonderful as the endless resourcefulness and creativity is, if you want your plant to thrive in its home, you should be mindful of its needs, and not just of the inventiveness of its location.
The crucial factors are:
Drainage: unless it is a water plant or other plant that specifically requires that sort of environment, all plants should have adequate drainage. There are a couple of reasons this is important. Firstly, most roots require air. If the little cavities in your potting medium are full of water, they won’t have the air the plant roots need to function. They will effectively drown and start to decay. Secondly, excess water will provide a different environment in your medium, which will encourage the growth of organisms suited to that environment. This may mean that fungus and bacteria that love overly wet conditions can thrive, and this can mean your plants are in trouble. Even if these organisms don’t directly threaten to harm your plants roots, they can use up nutrients your plant might need, and change the chemistry of the soil so that the roots may suffer.
How much drainage is enough?
That depends on your plant and medium. A loose coarse and friable medium may drain easily so that a single drainage hole is enough. This sort of potting mix may not be able to hold too much water in the first place. But some potting mixes can hold a lot of water. If your plant is large and leafy it may be ok with a little excess water as it might use it up fairly quickly anyway. However, if it is a cactus or succulent, or other plant that is prone to root rot, and the medium can hold a lot of water, then more drainage holes may be better for your plant. But I would certainly always choose the best potting mix for the plant from the beginning regardless of which pot I chose.
Another important factor to consider here is the permeability of the pot.
Pot permeability: If the container is made of unglazed ceramic, for example, the container walls may have some ability to allow water to pass through them. Terracotta is a good example. This can be a problem for some plants if they have a high water requirement because they may dry out too quickly. However, for a cactus or succulent, this can be very beneficial because they might be protected from their roots being exposed to overly long periods of dampness that can encourage fungal diseases and root rot. Glazed ceramic pots can be lovely but their glazed surfaces are not permeable, so this needs to be considered when selecting a pot. Plastic pots are also impermeable as are most containers. There are also pots made of fabric or biodegradable materials and some of the can be more permeable to water.
Pot size: The size of pot can be a very important factor in pot selection. You need to consider the size of the plant destined to live in that pot, the shape of the root ball, the rate of growth and even the life span of the plant and ease of repotting.
As always, the importance of these things can vary with plant type. Often, the current size is the main factor considered. The root ball shape can make a difference in some cases. Some plants have a shallow root system and simply don’t need a deep pot, so giving them one may lead to wasted potting mix and unnecessary weight to the pot. Some may have a tap root that wants to grow deeply and doesn’t need a lot of width. A single main root can also eventually grow so that it blocks a drainage hole. If there is only one drainage hole to begin with, this can cause water to remain in the pot and lead to decay. Desert roses (adenium) are an example of plants that are especially in danger of this.
If a plant is a fast grower then it is often best to give it a larger pot so it has growing room. But keeping it in a smaller pot may help stop it from getting too large and unwieldy if you want to control its growth. Bonsai is one practice in which pot choices intend for controlled growth.
Slow growing cactus and succulents are often best under-potted. This means the pot will always be the right size or too small but never too big. This is because they don't use up water quickly, and having a large pot will mean it will take longer for the potting mix to dry out. Too long a drying time will encourage fungal diseases and rot.
Plants that are annuals should be planted into their final location as soon as possible. This is because they will bolt to seed if their roots experience stress. Repotting unnecessarily may trigger this.
Whereas plants that live a long life may need to be repotted many times. If they are a plant that is sensitive to root damage, you may try to consider ease of repotting when choosing a container. Pots that are ceramic but have a narrower top that lower down will be challenging to repot without significant damage to the plant roots.
Using a Root saver at the bottom of your pot can reduce the damage your roots can experience when repotting. Root savers act like a moveable floor that you can push the root ball up with, out of the pot.
Pot shape: This can be very important for several reasons. If a pot is very short and has a large opening, it can dry out much quicker than a tall slim pot even if they have the same amount of potting mix. A much larger area of mix is exposed to the air so dries faster. A squat pot also can be problematic because the perched water table can occupy a much larger percentage of the mix, leaving much less aerated mix for the plant roots to enjoy. These are two opposite problems in the same type of pot, so the choice of medium and watering schedule will be important to find a good balance for your plants.
Rounded pots with a narrow opening can effectively create a damp ball that dries our slowly because the air doesn’t move as freely over the potting mix surface. These pots are also challenging to remove plants from, without damaging the roots or the pot.
The bottoms of pots should never contain an area that will allow water to pool inside. This can lead to decay.
Insulation: Most plant roots have preferred temperature ranges. Many plant pots and their locations can subject plants to temperature ranges outside of their preferred ones. If you live in a warm climate and your plants are exposed to direct sun, it is a good idea to have a suitable thermometer to measure the temperatures your plants roots are subjected to on a hot day. I have once taken a measurement of over 50C for the roots of a rose in a black plastic pot. Such a high temperature is very stressful for the plant.
Plants in warm conditions exposed to direct sunshine should have some protection from these temperature extremes. Insulated pots or pots made of materials not prone to heat up too much are a good start. Ceramic pots are generally a better choice than plastic for this reason. They also can help protect the roots from temperature fluctuations in general by slowing the flow of heat into and out of the pot. It is also possible to reduce the impact of these temperature fluctuations in many ways, such as shading the pot, using mulch or grouping pots together so they help shade each other. But it is important to always be mindful of air circulation around your potting mix.
Plastic pots are very carefully designed to be close to ideal and they have many good qualities. They tend to be wider at the top than the bottom which helps make repotting easier. They are flexible too , and not breakable, so can be tapped and pressed to help ease the plant out. You can even cut them away without damaging the root ball too much, and plastic is not expensive. They are usually designed with a bottom that is shaped with a raised central area and many drainage holes. This reduces the risk of problems caused by a perched water table after watering, by reducing the amount of water retained as well as increasing the rate at which the excess water evaporates away. They are also light and readily affordable. Their use makes wholesale nurseries economically viable.
However they don’t offer much protection against temperature fluctuations, and are not good for the environment. They are also impermeable to water so can, in some situations, encourage root rot despite their design.
Ultimately, there is no single factor that guarantees the success of your plant. It is about a combination of things and how they work together. Even if you choose the ideal pot, you may fail if the mix is too acidic for that plant, or it gets the wrong amount of sun, or you water incorrectly. However, you can improve your odds by considering as many factors as possible and learning from your failures. When you succeed in producing a lovely specimen of a favourite plant, it’s very rewarding.
The pots made by 9apes studio are stoneware and mostly glazed. The materials used are high quality and durable and designed to last a very long time. They have drainage holes and air channels to allow excess water to drain away readily, and for air to have some access to the root ball. Like all glazed ceramic plant pots, they would serve your plant better with a Root saver, to further improve the conditions for your roots, and to allow easy repotting with less chance of damage to your plant or pot.
Come and check out our range here:
https://9apes.com.au/collections/plant-pots