Rosemary (Salvia rosmarinus) is a herb well suited to the balcony: it grows in a pot of at least 20 L and needs 4–9 hours of direct sun a day. Below, the verified data and the practical notes for container growing.
Cycle and habit
container perennial; herbaceous clump or small aromatic shrub
In a pot it develops to roughly 40 cm tall and 36 cm wide. The exact final size depends on cultivar, climate and container — these figures are a reference, not a guarantee.
Light
Rosemary needs 4–9 hours of direct sun; acclimatise gradually.
If your balcony does not reach the minimum hours, choose the sunniest micro-climate: a south-facing, unshaded spot. For the full picture on sun by plant family, read Light on the balcony: how many sun hours per family.
Temperature and season
Grow in mild conditions and time sowing or repotting for the local climate.
It tolerates down to about 7 °C; below that, move it in or protect it from the coldest nights.
Substrate and drainage
Use a structural peat-free mix with mature compost and 20–30% drainage material; keep holes clear.
On a balcony the container is small and drains fast: keep the holes clear and empty the saucer after each watering. For what to put in the pot, read Substrate and drainage: what to put in the pot
Watering
Let the surface layer dry slightly between waterings.
Pot soil dries much faster than ground soil: check it every day, especially in the hot season, rather than on a fixed calendar. For the complete watering method, read Watering in containers: how much and when
Technical sheet
- Botanical name
- Salvia rosmarinus
- Sun
- 4–9 h
- Min. pot
- 20 L
- Min. depth
- 18 cm
Nutrition
Feed lightly: excess nitrogen can cause weak growth or reduce flavour, flowers and nodulation.
In a pot the available nutrients run out sooner than in open ground, so a light, regular feed is what matters — not large, infrequent doses.
Sowing and transplanting
Sow or transplant in the stated season; avoid root stress, keep the crown at the same level and harden off for 5–7 days.
When moving to the final container, go straight into a pot of at least 20 L and 18 cm deep, so you do not need to repot again soon.
Spacing
Keep about 20 cm between plants: the right distance improves airflow and slows the spread of diseases.
Harvest
Harvest or deadhead with clean tools when the useful part is well formed; do not remove more than one third of the canopy at once.
Harvest in stages, taking only what is fully developed, so the plant keeps producing for longer.
Common problems
- water stress
- wind or reflected heat
- aphids/mites or diseases encouraged by poor airflow
Prevention is the strongest lever: correct watering, good airflow and checking the plant from the start cut most problems before they start.
Pot and space
Minimum volume 20 L, at least 18 cm deep. One plant per pot is recommended.
A pot that is too small limits the root system of rosemary and makes the plant far more sensitive to heat and drought. If in doubt, go up a size.
