October gardening guide: what to do in your garden this October
By October, the garden looks autumnal, but the weather is quite capricious – it’s an Indian summer one day and a frost the next.
October gardening guide: Planting
Plant spring bulbs
Autumn is the traditional time for planting spring bulbs. Daffodils need to go in first in September and October; Tulips later in November. Timing is critical – especially for Tulips which need to be planted late.
It’s vital to get the correct planting depth to ensure flowering – too shallow, and they may not flower after year one. An easy rule of thumb is to plant the bulb 3 times its own depth, and you are unsure, plant deeper rather than shallow.
Planting perennials and shrubs
Whilst spring is a busy time for planting, autumn is also a good time for planting perennials and shrubs – the soil is warm, and there is less leaf growth, so the plant puts energy into roots. There’s also usually plenty of rain in autumn, before the weather and the ground gets cold.
This provides an ideal planting condition for almost anything except half-hardy plants, as they will not be sufficiently established before cold snap hits. Also, avoid planting drought-tolerant plants as the winter wet will be too much of an early challenge.
Plant winter pansies
This is a good time to plant winter bedding. The garden centres are full of pansies and violas, and they come home from the garden centre looking lovely, but often, after a short while, they seem to sulk, sometimes for the rest of the winter.
This can be because the bedding plants in the garden centre have had an ideal upbringing, in a temperature-controlled polytunnel, with near-perfect conditions. When you buy the plants, they are uprooted and plonked outside in the cold, wet chill. What do you expect to happen?
To avoid this, plant the bedding into the container that they will spend the winter in, and then place the container under glass in the greenhouse or in a sheltered spot. This will give the plants some time to get established and put down roots before introducing them gradually to the outside weather, as you would summer bedding. That way, the pansies and violas might actually flower through the winter.
Sow sweet peas
It is easy to germinate sweet peas in autumn, provided you can overwinter in a frost-free greenhouse or cold frame. Sowing in the autumn can produce sturdier plants for the spring, which gives you a head start when planting out, and they will flower earlier.
Germinate seeds in a warm place using root trainers. Although sweet peas can be grown in cardboard tubes, these are not ideal for overwintering because, over time, they will tend to disintegrate. Root trainers are much preferable for the autumn-sown sweet peas.
Sow one or two seeds to each pot, and when they have germinated and started growing, harden off on milder days outside, gradually getting the plants acclimatised to the colder weather and bring in under glass before it gets really cold.
Sweet peas are a hardy annual, which means they will tolerate the cold and frost even down to around -4°C. However, like all plants in small containers, they are more prone to their roots freezing. Hence, it is best to overwinter them in a greenhouse or cold frame to keep the worst of the winter weather away from the plants and roots.
Alternatively, you can start and grow them in the greenhouse under glass. The sweet peas will be fine in a greenhouse all winter and will need to be pinched out at the top growing points 2 or 3 times, depending on the growth rate. This will make the plants bush and produce more stems and, in the spring, more lowers.
Sow late lettuce and rocket
If you are sowing late lettuce and rocket in the vegetable plot, it may need protection with a cloche to ensure it germinates. Both lettuce and rocket are quite hardy and will continue growing well into late autumn and early winter.
Plant onions and garlic
In early to mid-autumn, garlic and onions can be planted to overwinter in the plot and get a head start on spring next year. In particular, garlic benefits from a chilly spell of at least a month of good cold weather for the bulbs to mature. Plant in autumn if your soil is not too heavy or waterlogged, alternatively plant into containers and overwinter outside if your soil is prone to waterlogging.
Plant in the usual way in autumn as in the spring, albeit slightly differently for onions and garlic, with both take care not to damage the base by pushing into the soil too hard. The roots sprout from this point. It is better to use a trowel or dibber. Keep a few spares to replace those which the pigeons will inevitably steal.
Pot tender herbs
Tender Herbs Basil, Coriander, Parsley, Dill & Mint cannot withstand frost, and it is best to pot them up and bring them under cover before any autumn chill. Whilst mint and Parsley are frost hardy, the winter damages it and the leaves are not relatively good. An indoor herb garden is handy, even with some hardy herbs in it, as it saves the dash out in the rain/sleet/snow to pick culinary herbs.
Pot up strawberry runners
If you have taken runners from the strawberry plants earlier in the year, now is a good time to plant them out. Before doing so, just check they are well rooted and then plant out well spaced in the strawberry bed, ready for next year. Plant them in an area of the plot which will be easy to cover with a net, which is essential if you want to enjoy the strawberries rather than the birds.
October gardening guide: Care and maintenance
The big clear up
By October, the garden can look messy with collapsing perennials, dying leaves and debris. Autumn is the time to clear up the garden and decide on which plants to cut back. It is down to personal choice and how much time is available.
The unsightly faded leaves of Delphinium, geraniums, and hosta are best cut back, but others with ornamental seed heads such as poppies, Allium, grasses are best left alone for now. Cut Peonies, Leucanthemum, Nepeta (Cat Mint) Delphinium, Hardy Geraniums, Phlox right back to ground level.
Slightly less hardy perennials such as penstemons are best left with the top growth in place. It provides some winter protection and should not be cut back until the spring to give some cover to the plant during the winter months.
After clearing and cutting back the borders – which often seems to take into November – it’s a good time to spread a mulch to help the more tender plants through the winter and improve the organic structure of the soil.
Now, until early winter, is the time to prune roses, especially climbing roses. This is a general prune, reducing the size by about a third to prevent wind rock. The long stems of the roses being caught by the wind causing wind rock – the plant moving around in the wind, which, in turn, loosens its footing and roots. Over time, the entry point of the trunk into the soil widens and allows in water and ice that can damage the plant and its roots. By reducing the top growth, there is less chance for wind rock.
This is a good time to divide up herbaceous perennials and move plants around. Many perennials flower less with time as they become congested. Dig them up, cut them into smaller pieces and pick out the best parts. Plant these new bits back into the previous site or add them to the border elsewhere and compost the old tired centre of the plant.
It makes sense to do this now because it’s quite difficult to dig out established plants, and often you’ll end up with a messy border. But it’ll be less of a disaster if plants get a bit trampled and trodden on in October, compared to May.
You’ll need to check individual plants. A rule of thumb is to divide every 3 to 5 years, but some plants, like Achillea, prefer more often, and others, like peony, don’t like to be disturbed at all.
If you have a plant that is failing to flower well, with a bald patch in the middle, chances are it needs to be divided. If the plant is very congested, you may need to hack at it with a sharp spade (or an old bread knife). Don’t worry – it will rejuvenate in the spring.
Protect tender plants
Bring under glass all half-hardy plants, which have had a summer outing, tender herbs – Chilli plants, Pelargoniums, citrus fruits, olive trees, and any tender exotics – before frosts bites.
Don’t throw away Pelargonium – often used as bedding plants. You can save money and have a lovely display of indoor colour by overwintering them in a frost-free but unheated greenhouse, conservatory or porch and bring them back out next year. There are so many types to choose from, and these tough plants will survive down just around freezing and tolerate the stifling heat of a conservatory in summer.
Lawn advice comes at the end of this long list of gardening jobs, as it’s such hard work, but autumn is a good time to work on the lawn. In September and October, depending on the weather, if it’s still warm enough to repair a patch by raking up the soil, covering it with compost and grass seed. The lawn can be raked to remove thatch, spiked to ease compacting and improve drainage, and given an autumn feed.
If all that sounds too much like hard work, just do one thing – rake up and remove autumn leaves because if left on the lawn, it will kill the grass underneath the leaves, resulting in unsightly patches.
October gardening guide: Harvesting
If autumn is mild, veg plants will continue cropping. Tomatoes are slowing down in the greenhouse, and depending on the weather, it may be time to cut them on the vines to ripen indoors. Tomatoes will continue to ripen slowly depending on sunshine and warmth levels in autumn.
To take care of tomatoes and encourage fruiting, continue to remove any faded or discoloured leaves to prevent disease. In addition, remove any flowers or tiny tomatoes that, by this stage, are unlikely to come to fruit before the weather changes completely.
The harvest in the vegetable plot is winding down as far as tender summer vegetables are concerned. If it remains warm, there may be a late crop of beans that will continue cropping slowly until frost.
Maincrop carrots can be lifted if needed or left where they can remain all winter. The only exception is if your veg plot is wet and heavy, overwinter the carrots may rot, in which case it’s best to lift and store them. After digging up, cut off the top foliage and store, in a cool, dark, dry place, such as a garage. Check regularly to make sure that there isn’t a rotten carrot to infest the rest.
October gardening guide: Wildlife and pests
Leave seed heads on some of your perennials as food for birds and small mammals. It’s also a good idea to create a log pile for overwintering newts and toads to overwinter in amongst an area of long grass. The grass will also attract birds that like to hunt for worms.
October gardening guide: Other garden tasks for October
Make a simple leaf mould bin
If your garden has deciduous trees, it is worth saving the leaves to make leaf mould. This is an excellent mulch for the garden, and when sieved, it makes good compost. It is easy to make a pen; just mould chicken wire into a bin with a stake in each corner to give structure.
Rake up and pile the leaves in, and they will rot down over the gardening year, ready to be spread on borders as mulch in the following winter/spring. You can tell when it’s ready as it will be well rotted and crumbly. If you have no space, you can store it in bin bags, but it is vital to put holes in the bag to allow the air to circulate. Otherwise, it will become a slimy mess.
October is ideal for seed collection for use next year. Nasturtium seeds are so easy to pick. They fall off the plant, store easily and germinate very well, providing lots of free summer bedding. They are a good place to start if you want to try saving and using seeds from your own plants.
Collect the seed heads and dry them out, at which point they will turn brown. Then take out the seed, carefully shaking or scraping out the small seeds and store packets in a dry place – a sealed tin is helpful. Label, because even if it looks distinctive now, it will be a mystery seed next spring. Once thoroughly dry, a good place to store it is in the refrigerator.
Save herbs for winter
This is also a good time to replenish dried herbs that lose their pungency after storage. Oregano, sage, thyme and rosemary are ideal for drying, although as hardy perennials, they can be picked all year round.
One method to dry herbs is to first blanch for just one minute and then strip leaves from stalks, lay them on a tray in the oven on the lowest setting with the door open to allow any moisture to escape. Leave like this for about 30 mins, and when cool, place in air-tight jars.
Another equally simple method is to pick them, hang them up to dry and then collect them into jars.