With the new month comes the beginning of autumn – meteorologically speaking. September ‘usually’ brings generally cooler and windier conditions than August, and the daylight hours are noticeably shorter. It is the time to reap the remainder of your summer harvest in the veg and fruit garden (and begin with the autumn crops) and for gently coaxing the last few colourful blooms from your summer flowers. It can be a time of special interest if you have grasses that turn to a golden brown and which combine well with ‘prairie’ style plants that bloom on into autumn along with Asters, Sedum and so on. It’s also a time of transition, as you bid farewell to this year’s growth and begin to prepare for next year with seed collecting, planting, propagation, lawn care and general tidying up. Here’s my top ten tips for September in the garden.
1. Continue harvesting fruit and veg
Especially autumn raspberries, plums, blackberries, the first apples and vegetables such as main crop potatoes. If you haven’t already done so, start thinking about storage (including freezing) of some of these for winter use. Root vegetables should be stored in a cool, dark and dry place. Leave parsnips in the ground for now, as they taste better after being frosted. Onions and shallots should be lifted (but do not bend them over at the neck as they won’t store as well) – if the weather is not wet leave them to dry on the soil, otherwise bring them into a dry shed. Any outdoor tomatoes (including green ones) should be picked before the first frost and brought indoors to ripen (placing them next to a banana will accelerate the process). Or you can remove a branch with them still attached and place the whole truss in a greenhouse or on a warm windowsill.
2. Careful watering
Be selective in watering new plants, those that are still looking green or are flowering or have fruit and veg you have yet to harvest. At the same time start to reduce the amount of water you give house plants. And make sure that established Camellias, Rhododendrons and Hydrangeas are well watered in dry periods, otherwise they won’t produce the buds that will form next year’s flowers. Ensure trees or shrubs planted in the last couple of years on lawns or in areas of rough grass have a circle of clear earth around them – this should be kept clear of grass which could prevent essential moisture getting through. Mulching with bark or compost will also help.
3. Collect and where appropriate, sow seed
Save seed from perennials and hardy annuals to get a start on next year. Continue to sow over – wintering veg seeds such as spinach, turnip, lettuce and onions.
4. Net work
Put nets over ponds before leaf fall gets underway, to prevent a build up of leaf litter and nutrients in the water and also cover vulnerable Brassica crops with bird-proof netting.
5. Greenhouse switcheroo
Once you’ve finished with your greenhouse for tomatoes, cucumbers etc. give it a good clean out (and cold frames too). Prepare it for over – wintering tender plants you want to bring inside such as Fuchsia or Pelargoniums before the first frosts. It’s worth insulating it with ‘bubble wrap’ as well as providing a form of heat to ensure the temperature never falls below 5 – 10 degrees C. After the first frost, lift Cannas and Dahlias and after removing the top growth, washing off the roots and drying them, store the tubers in a sandy compost mix in a greenhouse or other frost – free place. Alternatively, if they have been planted in a sheltered spot where frost, cold or wet conditions are rare you can try to leave them in the ground – but cover them with straw or bracken.
6. Nature nurture
Clean out bird baths and keep them topped up with water. Continue to put out small bird food (avoid peanuts and other larger stuff which is a risk to baby birds in the continuing breeding season). Resist the temptation to remove seed heads from plants such as Sunflowers, as they provide a useful source of food for birds (of course you can still remove some seed for your own use). Put a pile of twigs or logs in a quiet corner of the garden and this will become home to lots of wildlife – and perhaps make a natural feature of this area with primroses, ferns etc. Consider making or buying other wildlife ‘hibernation stations’ for hedgehogs, insects and other critters.
7. Prolonging the show
Continue with dead – heading and weeding so that you extend the flowering season and ensure soil nutrients and moisture benefit your plants and not the weeds.
8. Propagate, plant and prepare
Divide any large clumps of perennials or alpines. Most plants can be separated into many smaller pieces which can all be replanted (or given away) – discard the old centre of the clump. Buy and plant spring-flowering bulbs – Narcissus, Crocus, Muscari and Scilla especially, but wait a couple,of months before you plant Tulips. September is also a good time to plant out container – grown shrubs, trees, fruit bushes and perennials. Always soak the containers well before taking the plant out and fill the new hole with water before putting the plant in its new home (having ‘teased out’ the roots if it’s pot bound). Plant out new spring bedding such as Wallflowers, Primula and Bellis. Now is your last chance to put in new strawberry plants and pot up any rooted runners. Remove any canes that have fruited from summer fruiting raspberries and tie in the new canes, if you haven’t already done so.
9. Improve your soil
Sow green manures where the soil used for food growing would otherwise be bare over winter. If your soil is heavy clay, start digging it over now whilst it is still relatively dry. Add plenty of organic matter to improve the quality, and pea shingle to improve the drainage. It can be left over the winter when the cold will break the lumps down, making spring planting easier. Keep your production of compost and leaf mould going from the tidying up you are starting now. For compost, remember the rule of mixing 50% ‘green’ material and 50% ‘brown’ (including shredded paper and cardboard).
10. Lawn care
September is the ideal time for lawn repairs and renovation. First raise the height of the mower and mow less often. You can sow or turf a new lawn or repair bald patches or broken edges in an existing one. It is a good time to scarify (either with a long tined/spring rake or powered scarifier to remove the thatch and other debris) and aerate (by making holes all over the lawn with a fork or powered aerator). Then brush in, or spread with the back of a rake, sieved compost/loam/sand (depending on your ground conditions) and you can also add an autumn lawn feed (one high in phosphate to help root development). This can all be hard work, but you’ll notice the improved look of the lawn next year! If you have large areas of lawn, you could prioritise this work for an area that’s especially visible or near the house, or perhaps rotate around different areas of grass so that you give each one a periodic ‘facelift’ once every two – three years.
Old School Gardener
If you’ve enjoyed reading this post and others on this blog, why not comment and join others by signing up for automatic updates via email (see side bar, above right ) or through an RSS feed (see top of page)?