September gardening jobs: Preparing your garden for Autumn with The Garden Ninja

We're starting to see the transition from Summer to Autumn, so Lee is sharing his top September tasks to help keep it green and healthy...

As the lazy days of summer gradually give way to the cooler and crisper mornings of September, gardeners across the country start gearing up for a new set of gardening tasks.

September is a transitional month in the gardening calendar, signalling the end of summer and the beginning of preparations for the Autumn season, where plants move to dormancy, and there are a host of changes in our garden spaces.

Let’s delve into a variety of September gardening jobs that will help you maintain a vibrant and healthy garden throughout the autumn and beyond Ninjas.

1. Harvesting and Preserving

September is a prime time for harvesting a wide range of fruits and vegetables. Tomatoes, peppers, cucumbers, and beans are typically at their peak, so be sure to pick them regularly to encourage further production. Apples, pears, and late-season berries like raspberries and blackberries should also be harvested as they ripen.

Preserving your harvest is a great way to enjoy homegrown produce during the winter months. Consider canning, freezing, or dehydrating surplus fruits and vegetables to stock up on wholesome ingredients for your meals. Apples sliced will easily dehydrate in a low-heat oven, creating slices that can be used all year round. Alternatively, store them in crates with straw in between. Keep somewhere cool, and apples will last for months!

2. Collect Seeds from Perennials

If you have perennial plants that have gone to seed, September is the perfect time to collect them for future use, and it can be as simple as snipping off the seed heads into paper bags. Collecting and sowing seeds from your garden can save you money and allow you to grow your favourite varieties year after year. 

Ensure that the seeds are fully mature before harvesting them, which you can usually tell by giving them a shake, if they rattle, they are ready. Store them in a cool, dry place in labelled paper bags to keep them viable. Try and sow them the following year to ensure germination.

3. Lawn Care in September

Don't neglect your lawn during the month of September. September is an ideal month to give your lawn an autumn health check. Start by giving your lawn a good mow and then aerate it to improve soil aeration and root growth. If your lawn shows signs of wear and tear, consider over-seeding to thicken it up and fill in bare patches or scarifying the lawn to help open it up and remove moss or dead thatch.

Furthermore, September is an excellent time to fertilise your lawn. Choose a balanced, slow-release fertiliser that’s low in nitrogen to provide essential nutrients without promoting excessive growth. Be sure to water the lawn after applying fertiliser to help it absorb the nutrients.

4. Planting in September

While some may think of spring as the primary planting season, September is a fantastic time to introduce new plants to your garden as the soil is still warm from summer, which encourages strong root growth. The cooler temperatures reduce stress on young plants, and they need less watering.

Consider planting late-season perennials like asters and sedums to add a burst of colour to your garden if you want to extend the season. Planting in autumn means your garden gets a head start next spring, and quite often, plants are discounted at this time of year, so you can grab a bargain!

5. Bulb Planting

If you dream of vibrant spring blooms, now is the time to start planting spring-flowering bulbs like tulips, daffodils, and crocuses. The cooler soil in September encourages bulb development, setting the stage for a beautiful spring garden. The key to planting bulbs is always to plant them 3x their size in depth and water them thoroughly.

By planting spring flowering bulbs, you’re also helping out early-foraging honey bees and insects when nectar and pollen levels are at a low!

6. Dividing Perennials

Over time, perennial plants can reach their maximum spread and then become overcrowded, leading to reduced vigour and flowering potential. September is an excellent time to divide these plants, such as hostas, daylilies, and irises. Carefully dig up the clumps, separate them into smaller sections, and replant them in well-prepared soil. This not only rejuvenates the plants but also gives you the opportunity to expand your garden or share divisions with fellow gardeners.

It also helps boost your borders without spending a penny!

7. Garden Cleanup

As the month progresses, most gardeners tend to jump in early doors and cut everything back to the ground. However, I adopt a much more environmental approach, which is to leave the tidying up until February. This leaves structure in the garden when the frosts crisp up your herbaceous perennials. It also provides a habitat and late-season food source for birds and insects. Cutting everything down leaves you with bare soil, which can be a bit depressing to look at!

Consider adding a layer of compost mulch to insulate the soil, protect plant roots from freezing temperatures, and improve your soil!

September is a month of transition in the gardening world as the garden heads into a slower, sleepier period. But that doesn’t mean we can’t enjoy the garden, encourage wildlife and plan for spring.

So, roll up your sleeves, put on your gardening gloves, and enjoy the changing seasons in your outdoor oasis. Your efforts now will yield rewards for months to come!

Happy Gardening Ninjas!

About Lee

Lee Burkhill aka The Garden Ninja

Lee Burkhill aka the Garden Ninja is a multi-award-winning garden designer, horticulturist, garden blogger, vlogger, TV Presenter and YouTuber. Hailing from the North West of England, Lee has an infectious enthusiasm for helping gardeners all over the world. The Garden Ninja is his garden design business and online gardening blog, and he was recently voted one of the Top 10 Gardening Bloggers and Garden Vloggers in the UK. Lee is also part of the BBC Garden Rescue Team, which you can watch on weekdays at 3.45 pm on BBC One or on BBC iPlayer. Here at Lazy Susan, we’re looking forward to sharing his exclusive horticultural tips, tricks and advice on our blog.

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