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What to plant and sow in September

What to plant and sow in September

John, Passionate gardener, Cambridge

Guide written by:

John, Passionate gardener, Cambridge

92 guides

In September, your harvests should still be varied and plentiful. However, don't forget to make the most of the good weather to plant and sow for the upcoming seasons. From propagating to transplanting, here are our top tips on caring for your vegetable patch or decorative garden in September.  

Important features

  • Transplanting
  • Planting and seeds
  • Propagation
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Now is the time to sow any biennial or perennial flowers that will bloom the following spring and plant bulbs, such as:

  • cyclamen,
  • fritillaries (buried at least 10 cm deep!),
  • tuberous geraniums,
  • lupine,
  • larkspurs,
  • bergenias,
  • columbines,
  • hyssops
  • serpentine plants.

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September is also the ideal month to propagate certain plants including rose bushes , geranium, ageratums, sweet alyssum, anthemis and carnations.

You can also do the same for shrubs like phlomis, firethorn, barberry, evergreen cranberries and Japanese skimmia. To do so, take approximately 10 to 15 cm of a selection of last year's young stems that have started to go woody and remove the leaves on the bottom two thirds of the branch, before transplanting them into very loose soil.

The same can be done with perennials, such as daylillies, lillies of the valley or peonies. If you want to plant crocuses in your lawn, simply throw the bulbs over your shoulder and plant them where they land! This will help you to distribute your bulbs evenly for a natural look.

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Planting tools

September is the last month for sowing and planting many varieties of vegetables. Spinach sown at this time of year will be slower to go to seed. You should therefore be able to harvest until April. Cold-resistant varieties of spinach, such as 'Giant Winter' are very popular.

Winter lettuces can either be started in a nursery or planted directly. This includes iceberg, romaine and some cutting varieties. Keep in mind that the leaves at the base of the plant should never be buried.

Some turnip varieties can also be planted in September. One such variety is the 'Market Express', a small round white turnip that can be harvested just six weeks after sowing. This is the last month to sow any small radishes directly in the ground. Plant them in an open area so that they can enjoy as much sun as possible, since there is less of it. After harvest, do not discard the tops: they are very tasty in soups!

There's still time for leeks, cabbages and onions!

Now is the best time to plant your last round of leeks. It is also the final call for rocket and lamb's lettuce, which will normally be ready for harvest in early spring.

Sow any white-headed cabbages before mid-September. This variety of cabbage features smooth leaves and is more cold-hardy than its cousin, the savoy, which is known for its wrinkled or blistered leaves. The seedlings will spend the winter in a sluggish state of semi-life before quickly starting to grow again in early spring. It's important to choose the right variety for your garden (you can always ask your green-fingered neighbours for advice!).

In areas with mild winters, white onions should also be sown by September 15th.

At the beginning of the month, it's still possible to sow some herbs, like sage, oregano, chervil and coriander.

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Remove any dry leaves and some foliage from tomato plants to allow the fruits to ripen more effectively.

Your watering needs will decrease significantly – and you won't hear many gardeners complaining! Depending on the weather, you can switch to watering in the morning or continue to water in the evening.

Start blanching cardoons as required, depending on your needs.

Just like in August, it's important to be sure that there are no empty plots in your garden. Instead of leaving empty spaces, sow a green manure plant, such as mustard or a mixture of rye and winter vetch. These plants will eventually be ground up by the mower and left as ground cover until the next crop goes in.

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Bag your grapes to protect them from wasps and birds. While you're at it, you might as well remove any leaves that might prevent the sun from reaching the grapes. 

Collect any fallen fruit, included any that has been affected by worms. Alternatively, if you have the opportunity, let your hens out for a run in the orchard.

Trim your raspberry bushes after completing your final harvest.

Plant your strawberries 

Do not forget your strawberries! Anytime after September 15th is the ideal time to start your strawberry plants. Propagating strawberry plants couldn't be easier: simply take any young offshoots that have taken root on the runners and transplant them. If you want your plants to thrive, your soil must be very fertile. The best way to ensure your soil is high in nutrients is to plant right after a legume (beans, peas) or on soil that has been well-composted throughout the spring.

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Hedge shears

Mow the lawn once a week and if need be, wait until the rainy season starts  to sow a new lawn. Remember: if you want a luscious green lawn, you will have to take good care of it. You might want to scarify the lawn to inject air into the soil and allow the grass to take in nutrients more easily. Invest in an organic fertiliser and topdress the full surface of your lawn.

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Guide written by:

John, Passionate gardener, Cambridge, 92 guides

John, Passionate gardener, Cambridge

When I was young, I was already working in the family garden. Perhaps that is where my interest in plants and gardening came from. So, it was logical for me to study plant biology.   At the request of various publishers I have, over twenty-five years, written many books on the subject of plants and mushrooms (a subject that is close to my heart). They were mostly identification guides at first, but shortly after they were about gardening, thus renewing the first passion of my childhood.   I have also regularly collaborated with several magazines specialising in the field of gardening or more generally in nature. There is no gardener without a garden, I have cultivated mine in a small corner of Cambridge for the last thirty years and this is where I put into practice the methods of cultivation that will I advise you in as well.

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