How to grow geraniums on a sunny balcony in flats

A balcony brimming with life is the ambition of many people living in major urban centres. The geranium is an ideal choice for bringing colour to sunny spaces, pairing abundant beauty with remarkably straightforward day-to-day cultivation in comfortable flats.

How do you choose the right geranium for your space?

Two main forms of this species are sold for ornamental growing. The upright type develops in a bushier, vertical habit, while the trailing variety is widely recommended for creating attractive hanging planters or charming vertical gardens on a sunny balcony.

Both choices have very similar needs for ongoing care and maintenance. Understanding their growth habits makes it easier to arrange pots at home, ensuring every young plant has the right position to show its full ornamental potential and distinctive colour.

Here are the key characteristics of the two most common varieties of this plant:

• Upright Geranium: Has a clearly vertical, bushy growth habit in a pot.
• Trailing Geranium: Produces flexible stems that are ideal for hanging planters.
• Light Requirements: Both varieties need consistent direct sunshine.
• Efficient Drainage: They need a light growing medium to prevent root rot.
• European Charm: They create a flowering look reminiscent of Portuguese balconies.

How much sunshine does a geranium need to flower?

The key to plentiful blooms is directly linked to daily sunlight exposure. This plant needs at least six hours of direct sunshine to develop its flower buds with full vigour in the outdoor areas of your flat.

If it is kept in a shaded position, the plant will continue growing, but it will become leggy and weak. Insufficient light prevents the intense flowering that can turn any outdoor setting into a true garden filled with vibrant colours.

Below is a video from the Spagnhol Plantas YouTube channel that explores the points discussed in this topic in greater depth:

How should you prepare the ideal pot and growing medium?

Preparing the container correctly is essential, as this species dislikes waterlogged soil. Native to South Africa, it needs a generous drainage layer made from expanded clay or gravel to prevent premature rotting of the roots and support healthy growth.

The key tip for the growing medium

Perfect aeration

Mixing topsoil and coarse builder’s sand in equal parts greatly improves soil aeration.

This ideal combination prevents excessive moisture from building up, allowing water to drain freely after watering.

In addition, placing a drainage membrane over the stony material stops soil from washing through. This simple step keeps essential nutrients inside the pot, prevents the drainage holes at the bottom from becoming blocked and creates a perfect environment for the roots.

You will need the following materials to make an effective drainage system:

• Expanded clay or gravel to create the bottom layer;
• A drainage membrane or a protective piece of non-woven fabric;
• A light growing medium made from topsoil and builder’s sand.

What is the ideal fertilising and watering schedule?

To ensure spectacular flowering, fertilising plays an essential role in care. It is advisable to apply specialist fertiliser every fortnight, using water-soluble formulas in the watering water or foliar products sprayed on the leaves to provide the plant with suitable nutrition.

Watering should be done sparingly, only when the surface of the growing medium begins to dry out. Watering the soil alone and avoiding the flowers protects the plant from diseases caused by fungal infections that are harmful to proper botanical development.

The main guidance for feeding and watering your plant correctly is below:

• Fertilise every fortnight with products formulated for flowering;
• Use water-soluble or foliar fertilisers in line with the manufacturer’s instructions;
• Water moderately, directing water only onto the soil in the pot.

How can you prune for cleanliness and prevent disease?

Regular clean-up pruning is essential for keeping pathogens away from the plant. Use suitable scissors to remove yellowing leaves and faded buds, preventing dead material from using the vital energy required for new, healthy shoots.

Although these varieties are resistant to insects because of their aromatic oils, they are often affected by leaf rust. Applying fungicides monthly provides thorough protection, keeping the foliage clean and the stems ready to deliver a true visual display of striking flowers.

Read also: The hardiest plant to grow on the balcony: how to care for it and encourage flowering