August garden jobs – 12 flower, vegetable and maintenance tasks to do now for a productive late summer garden

August is a productive month for gardeners – crops are up for harvest, plants are up for pruning, and there's a long list of other August garden jobs that will help a garden survive the hot weather.

Whether you're wondering what to plant in August or hoping to lend wildlife a helping hand during the heatwaves, there's so much you can do to ensure your outdoor space thrives all the way through to the autumn.

Here's a list of key August garden jobs to get you started.

What you'll need

Flower garden tasks

1. Give your plants a trim

If you're wondering what to prune in August, there are plenty of options to keep your secateurs busy, from evergreen shrubs like hebes to summer-flowering plants like lavender.

There are also a number of plants you should deadhead in August to keep them flowering until the end of the season, from cosmos to repeat-flowering roses.

'Deadheading is one of the most effective gardening tasks to tackle in August,' says gardening expert Paul Parker from J. Parker’s. 'Removing faded blooms will encourage plants to continue producing flowers later into the summer season.'

Learning how to clean garden tools will ensure any cuts you make don't cause unnecessary damage or infection.

2. Collect seeds

Pruning isn't the only thing you can do with spent plants - you can also collect seed from many varieties to store for next year.

'During August, plants you might find are ready for seed collection include poppies, nigella, marigolds and some herbs,' says Morris Hankinson, founder and managing director of Hopes Grove Nurseries.

'Instead of deadheading old flowerheads, leave them on the plant to develop and dry out. At this point, you can either snip the seed head and shake the seeds out in a paper bag, or take the seeds straight off the plant.'

Morris also recommends keeping the seeds stored in a cool, dark and dry place over winter.

'A paper bag is a good idea, or a glass jar in a cupboard,' he adds.

Morris Hankinson

Morris Hankinson is the founder and managing director of Hopes Grove Nurseries Ltd, the UK’s only specialist grower-retailer of hedging plants. After graduating with a Commercial Horticulture Degree from Writtle College, Essex in 1992 Morris established the nursery the same year on a half-acre plot at the 25-acre family farm in Tenterden, Kent.

3. Take cuttings

There are plenty of flowering plants you can propagate in August for a string of free plants, from lavender to penstemons.

'Taking cuttings is a well known gardening technique that allows you to grow new plants from existing ones,' says Julian Palphramand, head of plants at British Garden Centres. 'Always use clean, sharp tools to take your cuttings, and try to do this in the morning when the plants are full of moisture.'

These Niwaki Sentei Secateurs are perfect for cleanly cutting thinner stems, and they're some of the best secateurs I've tried.

Vegetable garden tasks

4. Plant vegetables

If you’re keen to extend the growing season into the colder months or get ahead for next year, now is the prime time to sow more vegetables. In fact, the list of vegetables you can sow in August is long.

'As we move into late summer, there are still plenty of crops you can sow now and enjoy before winter hits,' says Abbie Betts, gardening buyer at Cherry Lane Garden Centres.

Abbie recommends sowing kale, spring onions and Swiss chard now for late-season harvests.

You can also sow cabbages like Cabbage 'April' from Thompson & Morgan for early harvests next spring. Or, browse a huge range of lettuce seeds at Amazon for speedy harvests before the end of the growing season.

5. Keep harvesting

If you’ve been busy growing vegetables all season, there’s so much you can harvest in August.

‘In the vegetable garden, it’s time to harvest any potatoes and onions,’ says David Glass, head gardener at Bowood House & Gardens.

You'll also need to watch out for signs your cucumbers are ready to harvest, and an array of other fruit and vegetables like tomatoes and courgettes. Keep a trug handy for Instagram-worthy snaps of your harvests, like this large wooden garden trug from B&Q.

6. Sow green manures

One of the best ways to prepare your soil for winter is by sowing green manures like mustard and phacelia, and you can get started this month.

‘If any beds are empty, August is a good time to sow green manure,’ says David. ‘It improves the soil and acts as a natural source of nitrogen for next year’s crops.’

You can pick up green manure seeds from Thompson & Morgan for just £1.99.

7. Feed fruiting crops

It's peak production season for fruiting crops like tomatoes, peppers and courgettes, and feeding them regularly will encourage their best crop.

'Keep your plants regularly watered to prevent them from drying out,' advises David. 'Use of a weekly tomato feed will help your fruit to ripen.'

Levington Tomorite from Amazon is a popular (and affordable!) choice. Or, you could learn how to make your own tomato fertiliser.

8. Keep an eye out for pests

You'll need to be on the lookout for garden plant pests like aphids and caterpillars this month, because they're just as attracted to the warm weather as we are.

'Be vigilant!' says Mark Dwelly, head gardener at Audley Stanbridge Earls. 'Regularly check tomatoes and potatoes for blight, and inspect others for aphids, caterpillars, and insect eggs.

'Act quickly to control any outbreaks by hand-picking pests or using organic sprays before they get worse.'

Caterpillars were one of the hardest lessons I learned when I first started growing in a raised vegetable bed.

9. Trim perennial herbs

Whether you’re looking to flavour your meat or garnish your cocktails, herbs are the plants of the moment and a fantastic addition to gardens of all sizes. Cutting them back now will reward you with another flush of harvestable leaves before the first frosts arrive.

'Cut back herbs such as chives, mint and parsley, especially those that look tired,' says Dobbies' resident gardening expert and horticultural director Marcus Eyles. 'This will encourage fresh new growth for a continued supply of leaves for summer dining.'

Other August garden jobs

10. Keep plants hydrated

As temperatures rise, soil moisture levels fall, so watering is paramount throughout August (especially during heatwaves!). When it comes to knowing how often you should water your garden in hot weather, it's important to make sure you're giving your plants a good soak without waterlogging them.

'Direct, deep watering straight to the roots of plants is best, as this is where moisture is needed,' says Marcus from Dobbies. 'Don't sprinkle the leaves of plants, as little water gets to the roots.

'Water new plantings, giving a thorough soak every few days. This encourages roots to grow down into the soil rather than towards the surface. Add a thick layer of mulch to help retain moisture.'

A drip watering system is a brilliant way to keep your plants hydrated at soil level, and micro-drip irrigation systems are often permitted during a hosepipe ban, too. The GARDENA Micro-Drip-System, which you can buy from Amazon, is ideal for tubs, troughs and containers.

11. Look after your lawn

After the sweltering summer we're having, it's worth having a few August lawn care tips up your sleeve, and learning the correct way to mow your lawn in hot, dry weather.

'For a formal lawn, regular mowing is best, but raise the cutting height in hot weather to help prevent it from drying out,' advises Marcus. 'Keeping the blades slightly higher also helps the grass resist the extra summer wear.'

There's also a right way to water your lawn in hot weather, but you might need to brainstorm ways to water your garden during a hosepipe ban if restrictions are affecting your area.

12. Lend wildlife a helping hand

Topping up water features like ponds and bird baths is a brilliant way to help birds in hot weather. It's worth learning how to regularly clean a bird bath, too.

You can also try creating a mud-puddling spot for butterflies to provide them with extra minerals and nutrients. 'Puddling is also a vital part of butterfly behaviour,' says Sean McMenemy, garden wildlife expert and founder of Ark Wildlife. 'When they’re not fluttering about, male butterflies often engage in mud-puddling as a way of charming the ladies!

'Creating a puddling spot for butterflies is easy. Simply mix some soil with water in a shallow dish, place it in a spot that gets a good mix of direct sunlight and shade, and keep it topped up with water.'

Which of these August garden jobs will you be adding to your to-do list?