When to plant Basil in Perth

Ocimum basilicum

Basil
Basil · Ocimum basilicum

Basil is a fragrant, tender herb whose leaves are a staple of summer cooking. Native to tropical regions, basil is treated as an annual in temperate climates like the UK because it cannot tolerate frost. It thrives in warm, sunny conditions and can be grown in garden beds or pots for a steady supply of fresh, flavourful leaves throughout the summer.

60 cm · Full Sun · Moderate Water

Calibrated to Perth · average last frost around 9 May

Sow indoors March to April, plant out May to June, harvest July to October. Typical frost risk October to May.
ActivityJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember
Sow indoorsNoNoYesYesNoNoNoNoNoNoNoNo
Plant outNoNoNoNoYesYesNoNoNoNoNoNo
HarvestNoNoNoNoNoNoYesYesYesYesNoNo

Growing guide

What to do through the growing season

Change the guide to see different planting timelines and tips.

Step-by-step guide to growing basil by starting seeds indoors and transplanting outside after the last frost.

  1. 01

    Sow Seeds Indoors

    28 Mar to 11 Apr

    Sow basil seeds thinly on the surface of moist seed compost in trays or pots. Cover lightly with vermiculite or a fine layer of compost, as they need some light to germinate. Keep at in a bright spot. Germination takes 7-14 days. Do this 28th March - 11th April.

  2. 02

    Prick Out Seedlings

    18 Apr to 9 May Dates as each sowing reaches this stage

    Once seedlings have their first true leaves, prick them out into individual pots filled with multi-purpose compost. Handle gently by the leaves to avoid stem damage. Keep in a warm, bright location. This step occurs around 18th April - 9th May.

  3. 03

    Pot On Seedlings

    2 May to 23 May Dates as each sowing reaches this stage

    When roots fill the small pots, pot on into larger containers (e.g., pots) to encourage strong growth before transplanting outdoors. Use a well-draining compost mix. This is done 2nd May - 23rd May.

  4. 04

    Harden Off Plants

    25 Apr to 9 May

    Gradually acclimatise plants to outdoor conditions over 7–10 days before transplanting. Start with a few hours in a sheltered spot, then increase the time outside each day. Protect from strong winds and cold nights. Harden off around 25th April - 9th May.

  5. 05

    Transplant Outdoors

    23 May to 6 Jun

    Plant basil outdoors in a sunny, sheltered spot with well-drained soil after all risk of frost has passed. Space plants apart. Water in well and consider using cloches or fleece if nights are cool. Transplant 23rd May - 6th June.

  6. 06

    Water and Feed Plants

    6 Jun to 9 Oct Dates as each sowing reaches this stage Optional · repeat every 2 weeks

    Water basil regularly to keep the soil consistently moist but not waterlogged. Feed every 2-3 weeks with a balanced liquid fertiliser to support leafy growth. Start feeding from 6th June and continue until 9th October.

  7. 07

    Pinch Out and Prune

    13 Jun to 9 Oct Dates as each sowing reaches this stage

    Regularly pinch out the growing tips and any flower buds to encourage bushy growth and prevent bolting. Harvest leaves from the top down, taking no more than one-third of the plant at a time. Do this from 13th June onwards.

  8. 08

    Harvest Leaves

    7 Jul to 4 Oct Dates as each sowing reaches this stage

    Harvest basil leaves regularly once plants are well-established. Pick in the morning for the best flavour, using scissors or pinching off stems above a leaf pair. Harvest from 7th July until 4th October for continuous supply.

Suggested varieties

Popular varieties of Basil to consider

Sweet Basil

The classic variety with large, aromatic green leaves, ideal for pesto and Italian dishes.

Greek Basil

A compact, bushy variety with small leaves, perfect for container growing and slower to bolt.

Purple Basil

Adds colour to the garden with deep purple leaves and a slightly stronger flavour, great for garnishes.

Basil guides by town

See how Basil timing shifts in other towns with different frost dates.