Balcony and Container Gardening That Survives August
2 min read · Last reviewed February 2026
Containers fail in heat, not in cold. Almost all of that comes down to volume.
A container is a closed system with a finite water reservoir and no groundwater to draw on. Every recurring container problem — wilting, blossom end rot, stunted growth, salt crusting — traces back to that.
Volume is the single most important choice
| Crop | Minimum pot volume | Notes |
|---|---|---|
| Salad leaves, radish | 10 L | Shallow rooted; a window box works |
| Herbs (most) | 10-15 L | Mint alone, it colonises anything shared |
| Bush tomato, pepper, chilli | 20-30 L | Below 20 L, daily watering becomes mandatory |
| Courgette, aubergine | 30-40 L | Heavy feeders and heavy drinkers |
| Dwarf fruit tree | 45 L+ | Repot or root-prune every three years |
Use potting compost, never garden soil
Garden soil compacts in a container, losing the air-filled porosity roots need, and it brings weed seed and pathogens. Peat-free potting compost with added loam holds structure far longer than a pure peat-free bark blend.
Group pots and mulch them
Clustered containers shade each other's sides and raise local humidity, measurably slowing water loss. A one-centimetre gravel or bark mulch on the surface cuts evaporation further, and pale pots stay several degrees cooler than dark ones in direct sun.
Feed weekly from midsummer
Potting compost carries about six weeks of nutrients. After that, every watering leaches more out of the drainage holes. A dilute liquid feed weekly is the standard, switching to a high-potash feed once fruit sets.
Run the numbers for your own project
- Plant Watering CalculatorHow often and how much should I water this plant?
- Houseplant Light MatcherWhich houseplants suit this window?
Keep reading
- Starting Your First Vegetable Garden Without Wasting a SeasonMost first gardens fail for reasons that have nothing to do with a green thumb. Here are the five that matter.
- Building Soil That Actually Grows ThingsFeeding plants is a short-term fix. Feeding the soil is what makes a garden easy.
- Storage for Small Rooms That Does Not Make Them SmallerSmall rooms do not need more storage. They need storage that stops interrupting the eye.