I remember my very first “garden”, in a small asphalt courtyard surrounded by brick walls. I placed a shallow plastic planter with a few cucumber plants. Without realizing it, I had made a series of mistakes: not enough sun, too small a container and irregular watering. With the heat, the soil dried out quickly and my poor cucumbers didn’t survive long enough to produce a single fruit.
Things have changed since then. After several moves, I now live in the city, in an apartment with a large terrace. My garden is entirely in pots. Although it’s ideal to grow in the ground, I’m able to grow herbs, vegetables and flowers with good yields and relatively little effort.
A container garden requires more attention, it’s true… but it’s entirely possible to get great harvests and a lot of pleasure out of it. Here are a few things you should know about creating a container garden – whether on a balcony, terrace or any other paved surface – that I wish I’d known when I was preparing my very first garden.
Location
Before you start planning your container garden, take the time to observe the characteristics of the space you want to use. The choice of plants depends directly on the conditions of this location, and you may need to adapt it to suit your plants.
Light
One of the most important factors influencing plant growth – and therefore the success of your crops – is the amount of light received. It’s essential to observe your chosen location at different times of the day and note the number of hours of direct sunlight. You can then classify the areas into three categories: full sun, semi-shade or shade.
Full-sun plants need at least 6 hours of direct sun a day to thrive and flower fully. Mid-shade plants, on the other hand, prefer a more moderate exposure, receiving between 3 and 6 hours of direct sunlight or filtered light, such as that passing through light foliage or fabric. Finally, shade plants tolerate or appreciate lower light levels, with less than 3 hours of direct sun a day, often at the beginning or end of the day.
This will enable you to adapt your choice of plants to actual light conditions. Don’t forget that sunlight varies with the seasons, depending on the angle of the sun, the presence of obstacles such as nearby buildings, and even the presence of leaves in nearby trees.
Wind
High up, as on many balconies, the wind can be particularly intense. Even on the first floor, surrounding buildings can create wind corridors or whirlpools. Wind can not only damage your plants, but also dry out the potting soil in containers more quickly.
To deal with this, you can choose plants adapted to windy conditions, install wind mitigation devices such as windbreak fabric, trellis or openwork panels, or opt for heavier or well-stabilized pots to prevent them from tipping over.
Water
All plants need water. Containers, on the other hand, do not offer this natural reserve. So you need to keep a close eye on the moisture content of your potting soil. In some cases, the potted garden is located under another balcony or a structure that blocks the rain: in this case, it’s doubly important to ensure good access to water.
If you’re lucky, there will be a water outlet directly on site. If not, you need to think about a practical watering method. Can you easily fill and carry a watering can to your plants? Do you have to go up or down stairs? Cross a narrow corridor?
Flexible garden hoses are available with adapters for indoor faucets (kitchen or bathroom), which can greatly simplify the job. You can also consider a water collector, provided the source is clean and free of toxic elements.
In any case, since potted plants need to be watered frequently, it’s important to think carefully about the method you use. This may even influence the location of your garden… or simply limit the number of pots you can realistically maintain without getting discouraged.
A Heavyweight Garden
The total weight of pots, once filled with soil and well watered, can be surprising. That’s why it’s essential to check the load-bearing capacity of your balcony or terrace, especially if the structure is made of wood or the building is old. Avoid grouping several heavy bins in the same place without assessing the risks, and start small: it’s better to add gradually than to have to move everything later.
Containers
After choosing a garden location, let’s take a closer look at the choice of containers in which to plant our garden. Whether you opt for pots, tubs, planters, window boxes, crates, barrels, grow bags, hanging containers, vegetable tables or wall-mounted structures, the most important factor when choosing containers is the presence of drainage. A container without drainage can easily lead to root rot. Drainage holes are essential to prevent water accumulation and root rot.
Dimension
When it comes to size, it’s best to think big. I rarely use pots less than 30 cm/12 inches in diameter, which is equivalent to about 20 liters of potting soil (a 5-gallon pail). For many demanding crops like tomatoes, I prefer containers of 40 liters (10 gallons) or more. It’s generally better to group several plants together in a large pot than to scatter a multitude in small containers.
The larger the pot, the better it retains water and the greater the thermal stability of the roots. Small pots, on the other hand, tend to overheat, drying out quickly and limiting plant growth, even if the total volume of small pots is equivalent to that of larger ones. Some perennials, shrubs and even small trees adapt very well to pot culture, provided they are given enough space to grow. Ideally, the diameter of the container should be about half the plant’s mature spread.
Material
Next, you need to choose the materials your containers will be made of, as well as their color. Plastic containers are lightweight, inexpensive, and retain moisture well, but their light weight makes them less stable in windy conditions. There are also environmental considerations. Terracotta pots are very attractive, but they are porous, which causes the soil to dry out more quickly. They are also heavy and fragile in freezing temperatures, so they must be brought indoors during the winter.
Geotextile growing bags offer good aeration and excellent drainage, while being very lightweight, but they dry out quickly and require frequent watering. Wooden containers, appreciated for their natural appearance and insulating power, need to be treated to resist rotting and can suffer damage over winter. Finally, metal pots are very durable, but tend to overheat in the sun, which can harm plant roots.
Color
The color of pots plays a more important role than you might think, especially outdoors. Dark-colored pots, such as black or brown, absorb more of the sun’s heat, which can help warm the soil more quickly in spring or in cooler regions. However, in midsummer, this accumulated heat can become excessive and stress roots, especially for heat-sensitive plants. Conversely, light-colored pots, such as white, light gray or beige, reflect light and keep the soil cooler, which is preferable for very sunny balconies or during heatwaves. The choice of color can therefore be a simple but effective tool for better adapting your containers to the climatic conditions of your environment.
Other Considerations
Several other considerations are important when choosing a container for outdoor plants. The shape of the container also influences its stability: a pot that is flared or narrow at the base is more likely to topple over in the wind. The weight of the container must be adapted to its location: on a balcony or high terrace, containers that are too heavy can cause problems, while in windy areas, a pot that is too light is likely to topple over. Mobility should also be considered: integrated handles or the addition of castors make it easier to move large plants. Last but not least, don’t overlook the aesthetic aspect!
Potting Mix
Since it is the roots that live in the potting soil and supply the plants with water and nutrients, the choice of potting soil is essential to their health.
Let’s start by clarifying the difference between soil and potting compost: garden soil, while suitable for planting in the ground, is too heavy and compact for containers. It drains poorly and can suffocate roots. For pots, use a light, airy potting soil that retains moisture and drains well.
Look for potting soils containing materials such as peat moss, coconut fibre, perlite or vermiculite. These components improve potting soil structure, promote aeration and ensure good water retention.
Make sure you choose a potting soil specially designed for containers. It may be sold under different names: “potting soil”, “potting soil for containers” or “potting soil”.
Some potting soils are enriched with slow-release fertilizers or organic amendments such as compost. Having said that, I find that the quantity is generally insufficient. So I systematically add 5-10% compost (by volume) and top it up with a suitable fertilizer, according to the plants’ needs and the instructions on the packaging.
Always choose quality potting soil: it’s the foundation of a healthy potted garden!
Climbing Plants
In general, if you grow in containers, it’s because you don’t have much space. Why not opt for a climbing plant? This allows you to grow more in a smaller space, while adding vertical visual interest that contrasts nicely with the rest of the planting. Some plants can cling to slightly rough surfaces, but most will need a support suited to their growth habit.
Voluble plants with a twining stem, such as morning glory or runner beans, wrap themselves around a support. They need a support with a maximum diameter of 4 cm/1-1/2 inches, such as a small post or thin trellis.
Plants with tendrils, such as peas or cucumbers, develop fine, specialized organs that seek to cling to thin elements. They climb best on a tight-mesh trellis or wire mesh, with uprights of up to 4 mm in diameter, around which they can easily wrap themselves.
Others, such as Virginia creeper, cling to a vertical surface on their own, using spikes or adhesive roots: they don’t need a trellis, but do require a rough wall such as wood, brick or concrete.
Finally, sarmenting plants, such as tomatoes, don’t climb on their own: they produce long, flexible stems that need to be hand-tied to a solid support, such as a sturdy trellis or tomato cage.
Ready for Action?
With all these basics in hand, you’re now well prepared to install a container garden suited to your space and conditions. But preparation isn’t everything.
In Part 2, we’ll take a look at how to put your container garden into action: from plant selection to watering, fertilizing, repotting and crop rotation, right through to overwintering.
Great information thank you