What to Plant in September: 15 Things to Grow in Your Garden Now

Published on: 02/09/2026 by Sophie Grant

Why September Is Such a Good Month for Planting

September is finally here, and you might be breathing a sigh of relief now that mother nature has decided to turn the dial down on the temperature gauge. (I know we are!) After having the hottest summer on record here in the UK, we are all feeling the anticipation of starting fresh this September. But what can we actually plant? And what makes September such an exciting month in our Gardening Calendars?

September is a very unique month because the soil is still warm, and the air isn't too hot. Warm soil speeds up plant metabolism so you get quicker, healthier growth, and strong, established roots before the weather turns too cold. The air temperature is mild enough so that plants no longer suffer from the intense heat we have had this summer, but is not so cold that they go dormant.

Planting in autumn is so amazing because it allows the plants to become established over winter so that they have a head start when spring comes. In this blog, we will give you helpful tips and tricks to make sure that your garden is beautiful and thriving by next spring!

Flowers to Plant in September

Perennials - The end of September is a great time to plant new perennials, because the warm soil and cool air means that the roots grow nice and strong, while the top is not stressed. This makes the foundations for beautiful, healthy plants in Spring.
Hardy annuals - Hardy annuals can resist the cool weather, so they also focus on building the foundations for beautiful blooms come next year. We are starting to find a common theme here! Some great examples include: Calendula, Poppies, Larkspur, Sweet Peas, Cornflowers and Nigella.
Spring bulbs - It is important to plant these before the ground freezes. Avoid planting Tulips until October or November to prevent "Tulip Fire". Some good options to plant now are Daffodils, Hyacinths, Crocus, Snowdrops, and Iris Reticulata and Muscari which establish particularly well in the arm early autumn soil.

Vegetables to Sow and Plant in September

Spinach - Opt for hardy varieties such as 'Matador' to ensure a harvest throughout autumn and early spring.
Winter Lettuce - Select cold-hardy types and place them in a sheltered area or beneath a cloche.
Salad Leaves & Rocket - These fast-growing greens flourish in the cooler autumn temperatures, offering fresh harvests.
Lamb's Lettuce - This variety is exceptionally resilient and can withstand harsh winter conditions, providing continuous salads.
Radishes - These quick-maturing vegetables make September your final opportunity to plant a late batch before winter.
Spring Onions - Sow winter-resistant varieties to guarantee an early crop for the following year.
Garlic - Plant individual cloves, pointy side up, in well-draining soil to develop roots before the frost arrives.

Spring Bulbs to Plant Now

Bulbs have a particular window of time when you should plant. They need to be planted before the ground freezes, but not while it is so warm that they become susceptible to diseases. Tulips are one that you must wait until late October to November, as they are sensitive to warm soils. If you plant them too early, they are likely to get a disease called "Tulip Fire".

However, September is still a great month to get started on some of your Spring Bulbs. Some great options for planting now include Daffodils, Hyacinths, Crocus, and Snowdrops. Iris Reticulata and Muscari thrive exceptionally well in the warm early autumn soil.

Other September Gardening Jobs

Divide Perennials - Spring or Autumn is the best times to divide your summer flowering perennials while the ground is dry enough to work. This autumn, the soil should be dry enough still to divide your perennials to avoid overcrowding, and get more plants for free!
Collect seeds - Many of the plants in your garden may have now gone to seed if you let them. Now is a great time to collect them, if you want more plants. Collect them on a dry, sunny afternoon to ensure that the morning dew has dried, and that the seeds are not wet. You will know if the seeds are ready to be collected if the seed heads are completely brown and dry. Alternatively, you can leave some of the seeds for the birds to have over autumn. Store them in paper bags or envelopes to ensure moisture isn't trapped, and don't forget to label them!
Refresh containers - Remember how we mentioned about the soil temperature and air temperature being perfect for establishment? The same happens to your plants that are potted in compost! Now is the best time to refresh those containers with some high quality peat free compost. After the constant watering needed over this summer, lots of nutrients would have leached out, and the compost may have compacted, leaving feed low and structure less than ideal. For the best plants, choose to repot in a compost that is full of nutrients and has great structure. Our Premium Compost is the best choice for peat free compost.

Should You Add Fresh Compost When Planting in September?

When refreshing your containers or sowing seeds, the best thing that you can do for your plants is choose a peat free compost that will give your plants the best start that you can. Now that we are moving to peat free compost, the quality and performance can vary a lot more that peat compost, which is mostly consistent. Peat free compost can be made of lots of different things, making different composts perform very differently. Our compost is made with the highest quality ingredients and is balanced for optimal plant growth.

Adding a light layer of fresh compost to your freshly planted bulbs, perennials and other plants helps to insulate the plant and protect the new root growth. You can save heavy top-dressing can be saved for late winter or early spring.

Your September Garden Checklist

September might mark the beginning of autumn, but there is still plenty to be excited about in the garden. From planting spring bulbs and dividing perennials to sowing flowers for next year and giving your containers a refresh, the work you do now will help set the stage for a beautiful garden in the seasons to come. So grab your gardening gloves, make the most of the cooler days and enjoy this quieter, golden time of year. And when your plants need a fresh start, choose a compost that helps them thrive.

So before September slips away, make sure you've: