Gardening jobs for September

September marks the start of Autumn, which means the nights will be drawing in and the weather starts to become more changeable. Make the most of your gardening jobs this month to bring in the harvest and make preparations for next year.

Gardening jobs in the veg garden

Ripen pumpkins

If you can, lifting pumpkins off the ground by placing them on top of a couple of bricks will ensure they get more sun and air circulation, helping them to ripen and reducing the risk of rotting.

Harvest potatoes

By the end of the month potatoes will be ready to harvest. Cut the tops off a couple of weeks before you want to harvest. This will help the skins to toughen and they should store better. Make sure you get every potato up (even the tiny ones) as these ‘volunteers’ will transfer any disease problems to next years crop.

Pick raspberries

Autumn fruiting raspberries should start to produce bumper crops this month. They tend to ripen over a few weeks so make sure they are picked regularly to keep them producing. If fruit is not picked it can rot and may spread to the unripe berries too.

Pick apples

Lots of apple varieties will start to ripen during September. You can tell when they are ripe as they will come away from the tree easily when twisted, and the seeds will be dark brown.

Plant onions

Hardy onion sets can be planted in autumn. The warm soils will ensure they put on roots and get established quickly. Plant them using a trowel so that the tip is level with the top of soil and don’t push them in as this will compact the soil underneath the bulb.

Cut back fruited blackberries

After all the fruit has been picked the older canes can be removed. The plants should already be producing long new green shoots which will need to be trained into the supports ready to provide next years crops.

Gardening jobs: Ornamentals

Order bulbs

It’s best to order spring-flowering bulbs as soon as you can. Supplies of the most desirable varieties can be limited so to make sure you get exactly what you want it’s best to get your order in as soon as you can. Daffodils and crocuses can be planted this month, but tulips can be planted slightly later.

Take pelargonium cuttings

These can be grown on in a heated glasshouse or even on the window sill to provide new plants for next year.

Saving seed

September is a great time to collect seed from your favourite plants. On a dry day cut off mature seed heads into a paper bag and label them. Fleshy berries and seeds will need to be cleaned of any pulp before they can be stored.

Divide herbaceous perennials

Any clumps of herbaceous perennials that look tired or haven’t flowered as well this year may need dividing. Dig them up, split them into sections and replant a few with plenty of fresh compost dug into the surrounding soil. Any extra sections can be potted up to swap with friends, or fill gaps in other borders in the spring.

Feed and deadhead hanging baskets

If you take care of your baskets they can continue flowering for another month or two. Once they start to fade they can be replanted with trailing pansies, violas, and ivy, but it’s worth adding a granular fertiliser to replenish the compost which will be exhausted from the summer display.

Gardening jobs for the lawn

Feed

September is a great time for renovating tired lawns. After a summer of growing most lawns will need a feed. Use a specific Autumn feed which will have less nitrogen (so it doesn’t grow as quick) but higher iron content which will kill any moss and turn the lawn a deep, verdant green.

Scarify

The iron in the lawn feed will turn any moss black. This is the perfect time to remove it by scarifying. Use a spring-tined rake, or a mechanical rake on bigger lawns to scrape any moss or thatch out of the grass. It will allow air circulation and help prevent any mould appearing on the lawn.

Re-seed

After a summer of use some patches may appear a bit bare. Rough them up with the rake to loosen the top surface and sow grass seed into the soil. The warm wet weather will mean they germinate quickly and the seedlings will build strong roots during the winter, ready for next spring.

Gardening jobs for the pond

Cover with a net

It’s a good idea to cover small ponds or water features with a net to keep any falling leaves out. If they settle in the pond they will break down, increasing the nutrients causing problems with algae and aquatic weeds next spring.

Gardening jobs in the greenhouse

Ventilate

September can be both warm and damp so mould or rot can quickly establish in the humid atmosphere.

Remove shading

Every bit of light is valuable at this time of year so now is the time to remove any shading

Ripen tomatoes

Any tomatoes that haven’t ripened can be taken inside and ripened on a window sill. Putting them next to bananas will help to speed the process.

Tidy up

Keep the glasshouse tidy, as any debris can harbour pests and diseases.

Gardening jobs: Pests and diseases

Powdery mildew

As plants come to the end of their season they will be prone to attacks of powdery mildew. This looks like they have been dusted with talcum powder. It is worse when plants are stressed by dry spell but is spread quickly by the following rain. It often signals the end for any squash or sweet pea plants. It’s a good idea to remove any leaves that show signs to prevent it spreading, but keeping plants well watered, and not wetting the leaves when watering can help.

Vine weevil

Keep an eye out for vine weevil damage. Plants damaged by these black beetle-like beasts will show notched damage along the edges of leaves. Their grubs can also eat through the fleshy roots of heuchera or cyclamen. If you look in the soil around damaged plants you may find small, white c-shaped grubs. They are worst in pots. While the soil is still warm, treat them by watering the soil with parasitic nematodes.

Gardening jobs: Pruning

Trim evergreen hedges

There’s still time to trim evergreen hedges like Yew and Laurel if they haven’t been done yet. Don’t leave it much later as it can stimulate them into new growth which won’t have time to harden before the first frosts.

Prune climbing roses

Cut back any shoots that have flowered to a couple of buds. Remove any dead, diseased or damaged growth, and tie in the vigorous new shoots to your support. This can also be a good time to remove any thick, old and woody growth that has become unproductive.

Plant suggestions for September