September Garden Diary

Our September Garden Diary is brought to you courtesy of Geoff Hodge from The Scotts Miracle-Gro Company.


As we move into autumn, temperatures start to drop and there’s always the chance of an early frost. Although there’s a risk of severe rainfall this month, there is conversely the possibility of lovely sunny weather – even an Indian summer heat wave! Keep an eye on the weather and treat your plants accordingly, watering wherever necessary in dry conditions.


For months of colour from winter to late spring, you can’t beat spring-flowering bulbs. Planting now will reap rich rewards next year – and years to come. September is the main planting month for these bulbs, but you can still plant in October and even November if you don’t get round to it now.

It is often recommended to leave tulips until November, but this advice is now seen as unnecessary.  Remember that there are lots of different bulbs to choose from, including Muscari (grape hyacinths), Chionodoxa (glory of the snow), Scilla, Ipheion, Galanthus (snowdrops) and Crocus. It’s also a good time to plant lily bulbs for a riot of summer colour.

Always buy top quality, top grade bulbs as they come with their flower buds in place and are guaranteed to flower in their first year – small, cheap bulbs may not.

As these bulbs will give you many years of pleasure, it pays to improve the soil thoroughly before planting. Dig in plenty of organic matter, such as Levington Organic Blend Soil Conditioner or Levington Organic Blend Farmyard Manure, and add Miracle-Gro Bone Meal Natural Root Builder to help improve root growth and establishment. Mix in more organic matter with the soil dug out from the planting hole.

If the summer bedding is starting to look scrappy and going over, remove it and replace with winter- and spring-flowering bedding, such as winter-flowering pansies, violas, polyanthus and primulas, wallflowers, sweet William and bellis daisies.

Time-to-plant-spring#B1C11EIt is important to plant these sooner rather than later to give them time to establish before the colder weather arrives. The bigger the plants by the end of autumn – the better they’ll perform.

Again, it pays dividends to improve the soil with organic matter and add Miracle-Gro Bone Meal Natural Root Builder at planting time.

Some autumn-flowering plants, especially golden rod (Solidago), Michaelmas daisies (Aster) and Phlox, may be attacked by powdery mildew disease at this time of year. If you see the first signs of the telltale symptoms, spray plants with either FungusClear Ultra Gun! or FungusClear Ultra. Keep an eye on other susceptible plants, including clematis and verbena.

Topical tip

Cut back the flowering stems of perennials that are fading and dying down. Those that produce attractive seed heads can be kept on for winter interest; the seeds are also useful food sources for birds.


Don’t be fooled by autumn showers. No matter how much rainfall your garden receives, your patio pots, planters and hanging baskets may still need to be watered regularly. Always aim to keep the compost evenly moist – not bone dry, then waterlogged. Regular feeding with Miracle-Gro All Purpose Soluble Plant Food, Miracle-Gro All Purpose Concentrated Liquid Plant Food, Miracle-Gro LiquaFeed or Levington Tomorite will help your plants to continue flowering until the first severe frosts.

Once your summer plants are past their best, replant containers with winter heathers, trailing ivies and spring-flowering bedding plants to ensure great displays through winter and spring. Remember to replenish the compost with fresh and add a Miracle-Gro continuous-release feed to keep the plants growing and flowering well. Miracle-Gro continuous-release feeds only release their nutrients when the plants need it, reducing the risk of over- and underfeeding and excessive leaching out of the compost through autumn, winter and spring.

Topical tip

Don’t forget that most spring-flowering bulbs look fantastic when grown in pots and other containers – including dwarf varieties in hanging baskets. It’s easy to pop in a few bulbs when planting up containers for some extra spring flower power! Get them off to the best possible start by using fresh Miracle-Gro potting compost.


The autumn is a big time for lawn care, in order to get it back into tip-top shape after the summer, and to get it ready for the onslaught of winter weather and the spring ahead.
The jobs you’ll need to get on with, in order, are:
• Clear away fallen leaves
• Kill moss
• Rake & scarify
• Aerate
• Top dress
• Feed

For full details on autumn lawn care and the jobs you need to do, visit –

A summer of heavy use, scalping the grass with a mower set too low and killing weeds and moss can all lead to dead patches on the lawn. This is a great time to reseed and repair these areas, and Miracle-Gro Patch Magic is the quick and easy way to reseed damaged patches.

Topical tip

If you intend to sow a new lawn this autumn, prepare the area now, ready to sow the seed later in the month or in October. Dig out all perennial weeds first, add EverGreen Enriched Lawn Soil and rake flat. Allow the soil to consolidate for two to three weeks, to allow weed seeds to germinate and then clear these away with Weedol Rootkill Plus.



Although the main vegetable seed sowing season has now passed, there’s still time to sow overwintering turnip, spinach, Oriental vegetables and overwintering onions.
In colder regions or for a quicker harvest, sow them in pots or cell trays of Levington Original Multi Purpose Compost or Levington Seed & Cutting Compost in a cold greenhouse or cold frame and grow on and plant out the young plants.

You can plant overwintering onion sets to provide an early crop next year.

Continue to feed tomatoes still in crop with Tomorite – as the days shorten, this liquid feed can be invaluable in helping ripen the last fruits of the season. This high potassium plant food will also speed up the ripening of sweet peppers, chillies and aubergines.

Time-to-harvest-main#B1C0F8Maincrop potatoes should be ready to harvest when the top growth starts to die down and has turned brown. Cut off the dead stem and then leave for 10 days before starting to dig up the tubers. When they are all on the surface, leave for a couple of hours or so for the skins to set and then sort according to their storage potential. Perfect tubers can be stored in hessian sacks, paper bags or dry cardboard boxes for storage in a well-ventilated frost-free shed. Any potatoes that show damage, blemish or slug holes should be used in the kitchen as soon as possible.

Topical tip

Sow some winter lettuce, such as ‘Winter Density’, that can be grown outdoors with some protection from severe weather, or Salad Bowl types, non-hearting, cut-and-come-again varieties that can even be grown in pots on the kitchen windowsill.


Now’s the perfect time to be ordering and planting all new fruit trees, bushes and canes. The soil will still be quite warm, and the roots will benefit from this warmth. This is particularly important for peaches and nectarines. Other fruit trees may have a higher tolerance of cold at the roots, and can be planted later in autumn if necessary.
Make sure the soil is well prepared with plenty of organic matter, so dig in plenty of organic matter, such as Levington Organic Blend Soil Conditioner or Levington Organic Blend Farmyard Manure, and add Miracle-Gro Bone Meal Natural Root Builder to help improve root growth and establishment.

Always plant at the same depth that the plant was originally growing and firm the soil around the roots.
Trees will need to be staked with a good tree stake and secured with two tree ties.

After planting, give the plants a good soaking to settle the soil and roots and to ensure fast establishment. Mulch the soil with a 7.5-10cm (3-4in) thick layer of Miracle-Gro Moisture Control Decorative Pine Bark or Levington Water Saving Decorative Bark, which will help retain moisture around the roots as well as keeping weeds away.

Regularly pick all fruit as it becomes ready. Don’t leave it on the tree or bush to become over-ripe but, at the same time, don’t pick too early or the full flavour won’t have developed. Most fruit is ready when it comes away easily in the hand.
Apples and pears are generally ready to pick when they readily part from the tree when lifted gently in the palm and given a slight twist. Pears are best picked when slightly immature. They should then be left a couple of days at room temperature to reach full maturity. Eat bruised and damaged fruit first.

Topical tip

Cut out the old, fruited canes of summer raspberries, blackberries and hybrid berries after fruiting and tie in new ones that will fruit next year. Cut out weak, forked or misplaced canes.


This is also the perfect time to plant all manner of new trees, shrubs, climbers, roses and hedges. Follow the planting instructions above for fruit.

Roses may be showing signs of powdery mildew, blackspot or rose rust. At this time of the year it’s a good idea to pick off all the leaves that are showing disease and dispose of them in the dustbin rather than on the compost heap. Before the end of September spray with RoseClear Ultra or RoseClear Ultra Gun!, and remember to start spraying your roses next year as soon as the first signs of these disfiguring diseases are seen and repeat regularly to keep them at bay.

Topical tip

Shrubs normally pruned hard in the spring – such as buddleia and lavatera – can also be cut back by up to half now, to prevent wind rock and neaten their appearance.


September is an ideal time to kill weeds in and around the garden, especially deep-rooted ones that can’t be dug out easily or grow so big that it would take too much effort to make it worthwhile.

For deep-rooted weeds, such as docks, stinging nettles, bindweed, thistles, brambles, couch grass and perennial ryegrass, all you need is Weedol Rootkill Plus or one of the formulations of Roundup.

If you find bindweed growing up through the stems of wanted plants or other weeds growing among your wanted plants and spraying just the weed leaves is an impossible task, that’s when Roundup Gel comes to the rescue. It is easy to apply the gel to the weed leaves without touching the leaves of your wanted plant.

Japanese knotweed is a garden weed nightmare – in some areas its presence in gardens is preventing affected properties from being sold, because it’s so difficult to control effectively.

But with a special application method and Roundup Tree Stump & Root Killer there is an answer for home gardeners. This weedkiller is applied directly into recently cut stems using the included pipette. This method of control was previously only permitted and used by professional weed controllers but is now allowed and recommended for amateur use.

It’s not unusual to see extensive slug and snail damage at this time of year. When you see signs of attack, you can protect susceptible plants with SlugClear Ultra pellets or liquid slug killer, SlugClear.

Topical tip

Now’s a good time to install water butts and water-collection systems to make the most of all the autumn and winter rain. If you already have water butts, give them a good cleaning out to help keep the water fresh.


As temperatures start to drop – don’t be caught out by cold nights. Move houseplants that have been enjoying the summer outside back into the house before the weather becomes too cold.

When bringing plants indoors, check carefully for any pests and diseases they may have picked up outside, in particular red spider mite, mealybug and scale insect. If any of these or other pests are present, spray with BugClear Ultra Gun!.
Inspect rootballs and compost for vine weevil larvae and treat where necessary with a biological control or BugClear Ultra Vine Weevil Killer.

As temperatures and light levels drop, your houseplants may start to slow down. This means they’ll need less watering – so be careful to check carefully as we kill more houseplants by overwatering than anything else!

Topical tip

Feed flowering houseplants every seven to 10 days with a liquid houseplant feed, such as Miracle-Gro Pour & Feed, to keep them flowering


Use plant protection products & biocides safely. Always read the label and product information before use.

BugClear™ Ultra Gun! and BugClear™ Ultra Vine Weevil Killer contain acetamiprid.
FungusClear® Ultra and FungusClear® Ultra Gun!™ contain triticonazole.
RoseClear® Ultra and RoseClear® Ultra Gun! contain triticonazole and acetamiprid.
Roundup® formulations contain glyphosate.
SlugClear™ Ultra and SlugClear™ contain metaldehyde.
Weedol® Rootkill Plus and Weedol® Gun!™ Rootkill Plus contain glyphosate and pyraflufen ethyl.
Products marked ® and ™, Miracle-Gro® and Levington® are trademarks of The Scotts Company LLC or its subsidiaries.
Roundup® is the registered trademark of Monsanto Technology LLC.


Photos ©Scotts Miracle-Gro®