Gardening in September in Ireland | What To Do

What to Sow in September

Sow overwintering salads under cover: winter lettuce, lamb's lettuce, claytonia, mizuna and mibuna. Sow spinach and chard for autumn and early winter harvesting. Green manures including grazing rye, winter tares and field beans can be sown on cleared vegetable beds. Sow hardy annual flowers like cornflowers, nigella, calendula and poppies for earlier flowering next year. Wildflower seed can be sown on prepared ground — autumn sowings often establish better than spring sowings in Ireland's mild, damp climate.

What to Plant in September

September is the ideal month for planting spring-flowering bulbs — daffodils, crocuses, alliums, muscari and hyacinths should go in now. Plant new perennials, shrubs and trees while the soil is still warm. Divide and replant established perennials. Plant garlic cloves outdoors. Plant Japanese onion sets for early summer harvest. Strawberry runners planted now will establish well before winter. Plant winter bedding including pansies, violas, primulas and cyclamen for autumn and winter colour.

What to Harvest in September

September brings the last of the summer bounty alongside autumn crops. Harvest apples, pears, plums, damsons, blackberries and autumn raspberries. Continue picking tomatoes, peppers, courgettes, runner beans and sweetcorn. Lift maincrop potatoes. Harvest pumpkins and squash when the skins are hard and the stems begin to dry. Pull up the last beetroot and carrots. Dig up celeriac and parsnips. Pick the last herbs and preserve by freezing or drying. Make chutneys, jams and pickles with surplus produce.

Lawn Care in September

September is the single best month for lawn care in Ireland. Scarify to remove thatch and moss. Aerate with a hollow-tine aerator or garden fork. Overseed bare and thin patches — the warm soil and autumn rains create perfect germination conditions. Apply an autumn lawn feed high in potassium and phosphorus to strengthen roots for winter. Lay new turf or sow new lawns. Reduce mowing frequency as growth slows. Raise the cutting height slightly towards the end of the month.

General Garden Tasks for September

Begin autumn tidying — clear spent crops, compost healthy material and dispose of diseased plants. Plant spring-flowering bulbs in borders and containers. Take hardwood cuttings of roses, buddleia, cornus and willows. Net ponds to catch falling leaves. Insulate greenhouses with bubble wrap. Move tender plants under cover before the first frost. Clean and store bamboo canes, garden fleece and crop netting. Service and clean garden tools. Start composting fallen leaves separately to make leaf mould — it takes a year but produces superb soil conditioner.

Ireland-Specific Tips for September

September in Ireland brings the first real signs of autumn, with cooler nights, shorter days and the beginning of the leaf-change season. Average temperatures drop to 12-15°C. The risk of early frost returns in inland areas from late September, though coastal gardens of Cork, Kerry and Dublin may remain frost-free well into November. September rainfall increases, particularly in the west, reviving lawns and providing welcome moisture for newly planted trees and shrubs. Irish hedgerows are heavy with blackberries, rosehips, haws and sloes — a forager's paradise.

Frequently Asked Questions

Plant spring-flowering bulbs in Ireland from September through November, with September and October being ideal for most types. Daffodils, crocuses, alliums, muscari, scilla and hyacinths should go in as early as possible to develop strong roots before winter. Tulips are the exception — plant these in November to reduce the risk of tulip fire disease. Plant bulbs at a depth of approximately two to three times their own height in well-drained soil. Add grit to heavy clay soil to improve drainage and prevent bulb rot.

Choose only perfect, unblemished apples for long-term storage — use any damaged ones immediately or for cooking. Late-season varieties store best. Wrap each apple individually in newspaper or place on slatted trays so they don't touch each other. Store in a cool, dark, well-ventilated place at 1-5°C — a garage, shed or unheated room is ideal. Check stored apples regularly and remove any that show signs of rot before they affect neighbouring fruit. Well-stored late varieties like Bramley can keep until March or even April in good conditions.

September is actually the best time to sow grass seed in Ireland. The combination of warm soil from summer, shorter but still adequate daylight hours, increasing rainfall and reduced weed competition creates ideal conditions for grass seed germination. Seed sown in September germinates quickly and establishes a strong root system before winter. The young grass will then grow away vigorously the following spring. Prepare the seedbed thoroughly, sow at the recommended rate, and keep the area moist until germination occurs in 7-14 days.

MCDS.ie is your trusted online store for plants, garden tools, and outdoor essentials. We help you create beautiful, low-maintenance gardens with quality products delivered across Ireland.

What To Do In Your Irish Garden In September