August 2025 Lunar Planting Calendar for Cornwall

Sowing, harvesting, and tending with the moon’s rhythm

August in Cornwall brings the sweet shift between high summer and the first signs of the turning year. Days are still warm, but the evenings draw in sooner, and the moon hangs a little brighter over the sea. For gardeners following the lunar calendar, this month’s phases offer clear opportunities to sow, transplant, harvest, and prepare — all in tune with the pull of the tides and the quiet turning of the seasons.

These guidelines are rooted in traditional lunar planting wisdom. Many Cornish gardeners and allotment groups report good results when working this way, but your own success will still depend on weather, soil, and the quirks of your local microclimate.

August 2025 Moon Phases (Cornwall, BST)

• First Quarter: August 1
• Full Moon (Sturgeon Moon): August 9
• Third Quarter: August 16
• New Moon (Black Moon): August 23
• Next First Quarter: August 31

Waxing Moon (August 1–8 and August 24–31)

The waxing moon favours above-ground crops, leafy growth, and flowers.

Sow & Transplant

• Tomatoes, peppers, aubergines, climbing beans
• Salad leaves, spinach, rocket, chard
• Hardy annuals and biennials such as calendula, cornflower, and forget-me-not

Cornish Heritage Tip
In sheltered gardens, try late sowings of Cornish cabbage — a hardy, traditional variety well-suited to the region’s mild winters.

Other Tasks

• Pinch out side shoots on tomatoes
• Water in the cool of the evening to reduce stress

Full Moon (August 9)

A moment to pause, admire, and harvest.

• Pick ripe vegetables and herbs before heavy dew or rain.
• Host a “moon harvest” evening — a tradition in some Cornish allotments where produce is shared with neighbours.

Waning Moon (August 10–22)

The waning moon draws energy down into the roots, perfect for sowing and tending crops below the soil.

Sow & Transplant

• Carrots, beetroot, radishes, turnips, spring onions
• Autumn brassicas such as cabbage and kale
• Fruit bushes and young trees — raspberries, currants, gooseberries

Cornish Heritage Tip
If you’re digging potatoes, now’s the time for Pink Fir Apple, a waxy heritage variety known for its nutty flavour and long storage.

Other Tasks

• Prune spent growth
• Collect and store seeds from annuals
• Weed and mulch beds to prepare for autumn planting

New Moon (August 23 – Black Moon)

A rare third new moon in a season, traditionally a time for stillness.

• Avoid sowing or transplanting
• Feed the soil with compost or seaweed mulch
• Plan and prepare beds for September’s work

Adapting for Cornwall’s Climate

Cornwall’s mild, ocean-influenced weather extends the season for many crops:

• You can sow salad greens and herbs late in the month for an autumn harvest.
• Use windbreaks in exposed gardens and monitor for blight in humid spells.
• Seaweed mulch is both a nutrient boost and a traditional Cornish soil tonic.

Printable August 2025 Moon Calendar for Cornwall

Cornwall Tip
Keep a moon-phase garden log this month. Record sowing dates, weather, and crop progress — by next year, you’ll have a personalised lunar guide fine-tuned to your own patch of Cornish soil.