Selecting your container

There are many different shapes, sizes and types of containers which can be used to grow plants. These vary from shop-bought terracotta pots, plastic urns, and halved oak barrels to recycled Belfast sinks, wellie boots and even baked bean cans! If you put your imagination to it, you can turn just about anything into a plant pot.

The main consideration when purchasing containers for plants is that you should aim to make them as big as your space and finances will allow. Larger pots provide a much more natural growing environment where the plants have access to more water, space and nutrients. They also need less watering than smaller pots – which can need to be watered twice a day in the height summer. If you’re not sure what size of pot will suit your garden, find a container around the house that’s about the right size (eg a bin, a cardboard box or a laundry basket) and put it in the spot. Stand back and consider whether it’s overpowering the space, too small to be noticed, or just right.

Grouping pots is a good way of making a bigger display, without having to fork out for huge containers. Putting a selection close to each other can also provide some shelter for each container, conserving water and warmth.

You should also consider the style of the container. If you’re looking for a formal, urban design then a smart metal pot or glazed ceramic would be a good choice. For informal, cottage style planting, traditional materials like terracotta or stone would be more appropriate. Plastic pots can serve both purposes, as they are now available in a wide range of designs to suit every style of garden. Depending on the type of container you choose, you may also have a choice of colour. Consider what you want to plant in it and choose accordingly, for example a bright blue, ceramic pot, with strikingly pink flowers cascading down it can look marvellous. However, if you planted the same blue pot with petite, pale blue flowers, you would hardly see the plant against the bold container.

There are pros and cons to each of the materials you can use for container plants. Some of the main problems are overheating, cracking in winter cold, not insulating enough, poor drainage, lack of water retention and weight. Below is a summary of the main materials used for containers and what the benefits and drawbacks of each one are:

Terracotta

Can crack in frost – always purchase frost proof, rather than frost resistant, pots if you’re intending to leave them out over winter.
Water retention isn’t great as the water can be absorbed by, and evaporated out from, the pores in the clay. However, for this reason drainage is relatively good.
They aren’t particularly lightweight, although there is a great variety in size and the smaller ones are relatively light.
So long as they are frost proof they should outlast the average gardener…unless you drop them!

Glazed ceramic

Should be frost proof, but be wary of bringing glazed pots home from holidays in warmer climates as they may not be resistant to colder temperatures.
The glazing helps to retain water.
Like terracotta, the weight of the pot varies significantly by its size.
Should last a long time, so long as you don’t drop them, although chips may be more obvious than with a terracotta pot.

Metal

The main disadvantage to metal pots is that they will heat up quickly in warm temperatures and can ‘bake’ the roots. Lining them with bubble wrap or polystyrene can help reduce this, and also increase their insulation against cold.
Metal pots can be very lightweight, it depends on the weight of the metal they are made from.
They should last a good few years, more so if they are rust-proof or checked regularly to deal with any rust.

Wood

Good resistance to cracking in cold conditions
Good insulation against cold or overheating.
Can be affordably home-made to fit accurately into the required space. Painting them can help them suit any design.
Can become heavy as the wood absorbs water.
Will rot over time, although lining them with plastic sheeting and treating them with a plant-friendly preservative will help them live longer.

Plastic/resin/fibreglass

These materials are very lightweight, so the containers are much easier to handle. However, the down side to this is that taller pots may be so lightweight that they blow over in the wind!
So long as the material is UV stabilised, the containers should last a long time and be resistant to cracking both in frost and sunlight.
Plastic retains water well as it is non-porous.

Stone

Stone containers are very heavy, so they are difficult to handle and dangerous if they can be pulled over by children, but they will not blow over in the wind and are unlikely to be stolen.
Stone will last a lifetime, but is a very expensive investment.

Lead

Lead containers are very heavy, making them difficult to handle, but very stable once in place.
Most good quality lead pots will outlive their owners.

Hanging baskets

Solid sided baskets are usually plastic and, therefore, have the same pros and cons as the plastic pots described above.
Open sided baskets (eg wire ones) are very poor retainers of water, which is why so many hanging baskets fail. Partially lining with plastic and other water retention aids can improve their water retention.
Open sided baskets also provide less insulation and protection from the weather, although lining them with bubble wrap can help improve this for winter displays.
Open sided baskets are often chosen because they give you the opportunity to plant in the sides, creating a more exuberant display.

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