The main jobs in the garden in August in the UK are keeping everything watered and fed through the driest weeks of the year, harvesting daily so crops keep producing, summer pruning fruit and trimming hedges and lavender, deadheading flowers, and sowing the salads, spinach and spring cabbage that carry you into autumn. It is a month of maintenance and picking rather than big projects.
That is the short version. The longer truth is that August is the month when the garden either coasts or collapses, and the difference is almost entirely down to water and picking. I have had Augusts in Oxfordshire where I went away for a fortnight and came home to bolted lettuce, split tomatoes and courgettes the size of my leg, and Augusts where twenty minutes a day kept the whole plot ticking over beautifully. This is my honest list of what actually needs doing this month, roughly in order of importance, and the jobs you can safely ignore.
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Keep on Top of Watering
Watering is the job that decides August. The beds are full, the plants are at maximum size and thirst, and the rain often is not coming. Water deeply two or three times a week rather than a little every day, because a proper soak pushes roots downwards while a daily sprinkle keeps them at the surface where they cook. Do it in the early morning or the evening so less is lost to evaporation, and aim the can at the base of the plant, not over the leaves.
The priority list when time or water is short: anything in a container first, because pots can dry out in a single hot day, then tomatoes, courgettes, beans and anything swelling fruit, then recent plantings. Established shrubs and lawns come last and will generally cope. Inconsistent watering is behind most of the August disasters people blame on disease, from split tomatoes to blossom end rot, and my guide to how often to water plants in the UK covers the details, along with the watering mistakes that quietly stress plants.
Harvest Little and Often
August is peak harvest, and the single most productive thing you can do is pick every day or two. Courgettes, beans, tomatoes and cucumbers all work on the same rule: the more you pick, the more the plant produces, because its whole aim is to set mature seed. Leave a courgette on the plant for a week and it becomes a marrow, and the plant slows right down thinking its job is done.
Runner and French beans want picking while the pods still snap cleanly. Tomatoes are best taken as they colour rather than left to hang, which also reduces splitting after rain. If your tomato plants are covered in flowers but nothing is setting, that is a common August complaint with a few specific causes, and I have covered them in why tomato plants stop producing fruit. Second early and maincrop potatoes are also ready to start lifting this month, so ease a root up and see what is under there.
Feed the Plants Still Working Hard
Anything producing fruit in a pot or growbag is running on empty by August and needs a weekly liquid feed, tomatoes especially. A high-potash tomato feed does the job for peppers, chillies, cucumbers and aubergines too. In open ground the need is less urgent, but heavy croppers still appreciate a fortnightly feed while they are producing.
Stop feeding permanent shrubs and roses by the end of the month though. Feeding late into the season pushes out soft new growth that will not harden before the first frosts, and it gets burned off in October. August is the last call for feeding anything woody.
Summer Prune Fruit, Hedges and Lavender
August is the traditional month for summer pruning trained fruit. Apples and pears grown as cordons, espaliers and fans get their new side shoots shortened now, which lets light onto the ripening fruit and keeps the shape tight. Summer-fruiting raspberries that have finished cropping want their old canes cut to the ground, keeping this year’s fresh green canes for next summer. Blackcurrants, gooseberries and cherries can also be tidied after fruiting. The Royal Horticultural Society has a good rundown of the method on its apple pruning and training pages.
It is also the month to trim lavender, once the flowers fade. Cut the flower stalks off and take a couple of centimetres of the leafy growth with them, but never cut back into the old bare wood, because lavender rarely regrows from it. I shear mine into tidy green mounds in late August and they hold that shape through winter, and there is a full guide in how to grow lavender in the UK. Hedges can have their last proper cut of the year now too, after checking for any late bird nests before you start.
Deadhead and Keep the Flowers Coming
Five minutes of deadheading every couple of days keeps dahlias, roses, sweet peas, cosmos and bedding flowering into October. The logic is the same as picking beans: stop the plant setting seed and it keeps producing flowers instead. Sweet peas in particular must be picked or deadheaded constantly, because the moment they set a pod the display is over.
The exception is anything you want seed or autumn interest from. I leave the last flush on my roses for hips, and seedheads on fennel, teasels and sunflowers stand handsomely into autumn and feed the birds. Deadheading is a job to do with a drink in your hand on an August evening, not a chore to schedule. BBC Gardeners’ World has a useful primer on the technique for different flower types in their deadheading guide.
Sow Now for Autumn and Winter
The sowing year is not over, and August is the month for starting the crops that carry you through autumn and winter: fast salads and radishes, spinach and chard, pak choi and oriental leaves, spring onions, and spring cabbage for that first fresh picking next March. Warm soil means everything germinates in days, and the cooling nights suit exactly the crops that bolt in high summer.
I have written the full month’s sowing list up separately in what to sow in August in the UK, including the drill-watering trick that stops late-summer sowings failing in dry soil. If you only do one sowing job this month, get spinach in, and my guide to how to grow spinach in the UK covers it from there. For timing anything else, the UK Vegetable Planting Calendar shows the whole year at a glance.
Look After the Greenhouse
Greenhouses cook in August. Open every vent and the door on hot days, damp down the path with a can of water in the morning to raise humidity, and keep shading in place. Red spider mite thrives in hot dry glasshouse air and can wreck cucumbers and aubergines in a fortnight, and humidity is your main defence against it.
Keep pinching out tomato side shoots and, towards the end of the month, take the top out of each plant a couple of leaves above the highest flowering truss. It feels drastic, but it sends the plant’s energy into ripening the fruit it already has rather than making more that will never mature. The side-shoot job is quick once you have the knack, and removing tomato side shoots shows exactly where to pinch.
Water Butts, Ponds and Wildlife
Keep bird baths and any shallow water topped up, because natural water is scarce for wildlife in a dry August and a saucer of water does more good this month than a feeder. Ponds evaporate fast, so top them up little and often, ideally from a water butt rather than the tap. If a hosepipe ban arrives, and August is when they do, grey water from washing up is fine for ornamental beds in the short term.
It is also worth letting a corner stay slightly untidy. Long grass, a log pile and standing seedheads shelter the frogs, beetles and hoverflies that quietly eat your pests, and Garden Organic explains how to put these natural allies to work in their wildlife gardening advice. The slugs certainly do not take August off, and if they are hammering your new sowings, how to get rid of slugs in the UK covers the defences that actually work.
Jobs You Can Skip in August
Do not plant new shrubs, trees or perennials now unless you enjoy watering them twice a day, because August-planted stock struggles in hot dry soil and the same plant put in during autumn will establish far better. Do not lay turf or sow a new lawn, for the same reason. Leave the existing lawn slightly long in dry spells rather than scalping it, and do not panic when it browns off, because it recovers with the September rain every single time.
Major pruning of spring-flowering shrubs is also best left alone now, as they have already set next year’s flower buds and cutting them means cutting the display. And resist tidying too hard generally. August untidiness feeds a lot of garden life, and the big autumn sort-out is only weeks away anyway.
Common Questions About August Gardening Jobs
What should I be doing in my garden in August in the UK?
The core August jobs are deep watering two or three times a week, harvesting crops every day or two so plants keep producing, feeding container plants weekly, summer pruning trained fruit and trimming lavender and hedges, deadheading flowers, and sowing salads, spinach and spring cabbage for autumn and winter. It is a month of maintenance and picking rather than big projects.
What can you plant in August in the UK?
August is a good month for sowing fast crops such as salad leaves, radishes, spring onions and turnips, plus hardy crops like spinach, chard, pak choi and spring cabbage that crop through autumn and winter. It is a poor month for planting new shrubs, trees and perennials, which establish far better in the cooler, wetter conditions of autumn.
Should I water my garden every day in August?
Generally no. A deep soak two or three times a week is better than a light daily sprinkle, because it encourages roots to grow down rather than sitting at the hot surface. The exception is containers and growbags, which can dry out in a single hot day and often do need daily water in August.
When should I trim lavender in the UK?
Late August is ideal, once the flowers have faded. Cut off the flower stalks and a couple of centimetres of the leafy growth to shape the plant into a tidy mound, but never cut back into old bare wood, as lavender rarely regrows from it.
Is it too late to prune fruit trees in August?
No, August is exactly the right time for summer pruning trained apples and pears grown as cordons, espaliers and fans, shortening the new side shoots to let light onto the ripening fruit. It is also the month to cut the fruited canes of summer raspberries down to the ground. Major structural pruning of free-standing apple and pear trees waits for winter.
Why has my lawn gone brown in August?
Drought. UK lawns commonly brown off in a dry August and it looks worse than it is, because the grass is dormant rather than dead. Avoid cutting it short, keep off it where you can, and it will green up again within weeks of the September rains without any reseeding.
Should I stop feeding plants in August?
Keep feeding crops that are still producing, especially tomatoes and anything in containers, but stop feeding roses, shrubs and other woody plants by the end of August. Late feeding pushes out soft growth that will not ripen before the frosts and gets damaged in autumn.
A Sensible Place to Start
If the list feels long, it boils down to a simple daily loop: twenty minutes each evening with a watering can and a trug, picking what is ready, pulling the odd weed, and deadheading as you pass. Do that most days, get one decent sowing of spinach or salads in, and give the lavender its trim before the month is out. That is a well-run August.
This piece follows on from June gardening jobs in the UK and May gardening jobs in the UK in the monthly series, and pairs with what to sow in August in the UK for the full sowing side of the month. September brings the start of the autumn planting season, and with it a very different jobs list.