Gardeners urged to avoid key mistake in September - 'breeding ground for pests'

Gardeners have been urged to avoid two key mistakes in September that can wreak havoc for your plants. As summer comes to an end and autumn sets in, many gardeners are making the best of the remaining warm soil to prepare their gardens to flourish after the chill of winter has receded.

But Emma O'Neill, head gardener at sustainable gardening charity Garden Organic has flagged a couple of common pitfalls plant lovers fall victim to in September, and what to do instead. Asked what mistake gardeners often make this month that can hamper future growth, Ms O'Neill told Express.co.uk: "As September rolls in, temperatures generally drop, and light levels are lower.

"Overwatering at this time of year can cause plants to rot and create root deficiency problems. So, reduce watering and save more of this precious resource."

She also warned that leaving plants in the ground that have already died "can be a breeding ground for 'pests' and diseases".

"While it's important to leave some plants in situ, with valuable seed heads for wildlife, soil hygiene is key," the gardenening guru added.

She recommends clearning "any plant debris and leaves that you can and mulch your soil with well-rotted organic matter".

Ms O'Neill also flagged a range of important jobs to get done in September, including collecting seeds from plants like calendula, eryngium, sweet pea and marigold to use in future.

"Ensure they're adequately dry (don't do this on a wet day), put them in an envelope with the date of collection and the plant name and store them in a dry, cool place ready to sow next year."

"You can also divide summer flowering perennials now, such as Achilleas, Hostas, Agapanthus and Rudbeckias," she added.

"Plants benefit from division every three to five years to prevent overcrowding, allow good air circulation and encourage new growth."

She added that it's a good idea to water the plant first to make the soil easier to get through.

"Use two forks back-to-back to carefully split the plant. If the clumps are large, you can repeat this process. Make sure each part has a nice root and plants as soon as possible."

The plant aficionado says you can also extend your food-growing season with winter lettuce, rocket and spring cabbage.

"Late September-planted garlic and onion sets will put on good root growth, and they'll be larger plants. I also find this takes some of the pressure off the following year!

She also recommended planting "spring flowering bulbs such as daffodils, crocus and hyacinth (and alliums in late September) to ensure you have a beautiful spring display - and plenty of early pollen for pollinators - right through to the end of May".

"Check the bulbs are not soft, as these won't be viable, and ensure they've been stored in a cool, dark, well-ventilated place before planting," she added.