Even when the days start to get shorter, there’s still plenty you can do to help extend the summer season and keep your garden looking great until fall comes to pass and winter sets in.
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There are crops to harvest, perennials to divide, seeds to collect, and everything needs water as the growing season moves on.
And that makes August and September a time for maintenance, propagation, and upkeep in the Northern Hemisphere.
To keep your garden looking great now and throughout the year, join us for a look at 17 tips to keep your late summer garden going strong!
Here’s where this garden path leads…
17 Tips for Your Late Summer Garden
Right, let’s get into these tips and so you can see why they’re important for a strong garden!
1. Collect Seeds
By the time August arrives, many plants have finished flowering and set seed, ripening in the warmth of the summer sun.
Once mature seed heads have turned from green to beige, brown, or gray, collect flower seeds by cutting seed heads from the stalk.
Separate the seeds from the chaff and place in small, lidded containers or paper envelopes – remember to date and label them!
Store in a cool, dark, and dry drawer or cupboard until planting time next year.
2. Care for Containers
As the growing season wears on, container plants are often the first to show signs of heat fatigue, with leggy plants, fewer blooms, and tired foliage.
To keep your planters vibrantly colorful for the entire season, ensure they’re watered regularly and continue to fertilize through the entire growing season as outlined in our six simple tricks to keep your containers looking great.
For potted veggies like cucumbers, tomatoes, peppers, and so on, regular watering and feeding are crucial for an abundant harvest – check our guide to growing vegetables in containers for all the details.
3. Cut Back Lightly
When perennials start to look raggedy or overgrown late in the season, a light trim can revive appearances.
Cut away dead or dying branches and spent flower stalks, and trim out brown or wilted foliage.
For long, unruly stems, head back this year’s growth by up to one-third. But use a light touch and avoid pruning hard late in the season because it encourages new growth.
New growth that hasn’t hardened off is more easily damaged by frost and freezing temperatures, which opens the entire plant to destructive cold damage.
4. Deadhead Spent Flowers
Many annual and perennial cultivars are bred so that deadheading isn’t required for the plants to rebloom or maintain a tidy appearance.
But many varieties that do self-seed benefit from the regular removal of spent flowers, diverting energy into making more flowers, not seeds. And deadheading also prevents aggressive self-seeding!
Use clean, sharp shears to snip flower heads weekly, which also encourages a light, late rebloom in many plants.
If you do want some plants to self-seed, or you wish to collect seeds, allow a few seed heads to remain and shake or gather them when ripe. When you’re finished, deadhead to tidy things up.
If you’re unfamiliar with the practice, our guide on how to deadhead blooming plants is a great place to start.
5. Divide Perennials
Most perennials are best divided in spring or fall, because hot temperatures can make it difficult to establish new roots. But there are some that need to be divided in late summer.
Species such as bearded iris, foxtail lilies, and oriental poppies flower in late spring, go dormant in summer’s hot sunshine, and then revive as the temperatures cool off. And they need to be lifted and separated when they’re dormant.
After flowering, allow the foliage to dry out and die back. Water the plants well, soaking the roots deeply to make them easier to lift and split.
After dividing and transplanting, be sure to water divisions well to settle them into their new locations and apply water regularly until they’re established.
6. Fertilize Lightly
If late summer is hot and dry in your region, it may be wise to hold off on fertilizing your plants.
Feeding plants already stressed from high heat or drought conditions doesn’t help to revive them and may cause more damage than good – the roots and foliage of weakened plants are more susceptible to burning from fertilizer salts.
Instead, continue to water heat-stricken plants and trim them back by one-quarter if needed, then wait until temperatures cool off late in the season before a final feeding.
Or you can fertilize lightly with a one-quarter strength solution of liquid or water soluble fertilizers but avoid full strength applications.
7. Harvest Summer Crops
Reaping your own tasty, healthy crops is truly one of the highlights of the growing season!
And late summer is when the harvest and preservation of herbs, fruits, and veggies goes into full swing.
Continue to pick daily in smaller amounts for your personal use and put up surplus amounts of produce as frozen foods, dried goods, preserves, or root cellar stock.
For instructive and inspirational articles on preserving foods, check out our sister site, Foodal, for all the know-how on the best food dehydrators, how to start canning your own foods, making jams, jellies, and preserves or pickles, and how to preserve fresh herbs.
You can also read more about drying tomatoes and dehydrating homegrown produce for long-term storage.
8. Lawn Mowing Tactics
To keep your lawns looking luscious and healthy, raise the cutting height of your lawnmower blade by midsummer.
Allowing blades of grass to grow longer helps to keep the roots cool and reduces water evaporation, resulting in healthier plants.
Mowing is stressful, and lawns recover quicker when cut in the cool of evening and not during the afternoon’s heat.
Also, August and September are good times to reseed your turf if it’s watered regularly.
9. Mulch for a Cooling Touch
A summer mulch is like a soothing comforter, reducing stress in plants by keeping the soil temperature down, cooling the roots, and retaining moisture for longer by slowing evaporation.
Many types of natural materials make an excellent mulch.
Grass clippings, kelp, leaf mold, pine needles, untreated sawdust, small pine boughs, and straw all work well. As the materials decompose, they release micronutrients into the soil and improve the soil structure, or tilth, as well.
And a mulch is effective for low-maintenance gardens as they keep the weeds down too, reducing your time spent on this onerous task!
Spread a two- to four-inch layer of mulch evenly over the root zone and out to the dripline, but keep materials a couple of inches away from the crowns and stems of any plants susceptible to issues like crown rot or root rot.
If desired, you can leave your mulch in place over winter to protect roots from cold damage, provided there are no obvious pest or disease problems.
Or, if no pests are present, natural mulches can be dug into the soil in fall.
Should your plants have insect or pathogen problems, remove the mulch in autumn and dispose of it in the garbage or by burning it. Don’t add it to your compost.
10. Replace Early-Flowering Annuals
To keep containers and beds colorful all season, remove early-flowering annuals by midsummer and replace them with fast-growing heat lovers, such as angelonia, ageratum, coleus, salvia, sweet potato vine, and zinnia.
But don’t toss the early annuals – cut them back by up to one-half and move them into a background spot or a container so you can enjoy a late-season rebloom once temperatures cool down.
11. Self-Seeding for Easy Propagation
Self-seeding is an easy and economical way to propagate certain annuals, biennials, flowering bulbs, herbs, and perennials.
When seedlings appear the following spring, they can be left in place or lifted and transplanted to a more desirable location once they’re about six inches tall.
Species and open-pollinated plants are the best choices for self-seeding because the seed from many hybrid cultivars won’t reproduce true to the parent plants.
A partial list of abundant self-seeders includes:
- Annuals – cosmos, nasturtiums, and snapdragons
- Biennials – foxgloves, poppies, and sweet williams
- Bulbs – alliums, crocosmia, and muscari
- Herbs – oregano, parsley, and sage
- Perennials – borage, columbine, and delphiniums
Along with propagating new plants, when seed heads are left in place they provide an important food source for visiting birds.
12. Set Out Summer-Blooming Bulbs
Most of these plants are cold tender, so they’re typically planted in beds and borders in mid- to late spring after all danger of frost has passed.
13. Start Cool-Season Crops
Mid- to late summer is the ideal time to plant late-season, cool-weather crops that are harvested in autumn, or overwintered and picked early the following spring.
Excellent late-season veggies include broccoli, beets, Brussels sprouts, cabbage, carrots, cauliflower, kohlrabi, leeks, radishes, and scallions, plus many leafy greens as well, including arugula, collards, kale, lettuce, mustard, spinach, and Swiss chard.
Some vegetables, like Brussels sprouts and kale, enjoy and even benefit from a touch of frost, but many leafy greens will blacken from frost.
A simple solution to extend the fall season is to add a floating row cover, which effectively protects tender foliage against nippy temperatures.
14. Stir and Water Compost Bins
By summer’s end, there’s plenty of new material in garden composts bins.
If your bins have lots of new green materials like grass clippings and pruned foliage, add a thin layer of soil over the top.
This helps to speed up the breakdown process and develops a nice humusy base to aid in the breakdown of dry brown materials which are added later in fall.
For bins with no new materials that are already decomposing for use next spring, use a garden fork or compost auger to loosen and aerate. This allows air and water to percolate evenly throughout the layers for even, thorough decomposition.
And all bins should be watered in hot, dry spells – water is needed for bacteria and insects to turn waste materials into garden gold!
If you’re new to this practice, be sure to check out the basics of composting.
15. Watch for Pests and Disease
Along with weeding, monitoring for pests and signs of disease needs to be maintained for the entire growing season.
Remove insects manually with a strong spray of water from the hose, or treat with natural pesticides like neem oil, which is also effective against many pathogens.
To help prevent problems from occurring, ensure plants are spaced for adequate air circulation, water regularly, and plant in well-draining soil.
You can find Bonide Neem Oil in pint, quart, and gallon sizes at Arbico Organics.
16. Water On
Few things can turn a lush garden to tatters faster than a lack of water.
In many areas, rainfall is inadequate in late summer. Most annuals and perennials need an average of one inch of water per week.
Lawns and turf need to be watered frequently in hot weather to prevent the onset of dormancy, and trees and shrubs typically need about two inches of water per week in dry spells.
Water slowly and deeply to ensure the entire root ball receives moisture, which helps roots to grow deep.
Also, avoid watering the foliage to inhibit the spread of pathogens. A drip or soaker irrigation system on a timer is an easy and economical way to complete your weekly watering tasks.
For ideas that work best for your garden, be sure to read up on hydrating your landscape.
17. Weed Before They Seed
One thing a gardener can always count on is the challenging, regular, and persistent appearance of weeds…
They thrive in hot temperatures, quickly stealing nutrients, sunlight, and water from the plants you want to grow!
To keep weedy growth in check, schedule pulling weeds on a regular basis when they’re young and small. Get out there and complete this task weekly if possible.
If you can’t get at them regularly, be sure to remove garden weeds before they set seed. A single dandelion plant can produce up to 2,000 seeds – a potential scenario many gardeners would not want to deal with!
Our guide on how to spend less time weeding has many helpful tips.
The Talk of the Neighborhood
A few simple practices can help ensure your garden stays strong through late summer, and all year long!
Keep things cool with a summer mulch, and colorful with late summer bulbs.
Stay on top of chores like pest patrol, watering, and weeding as well as propagation practices such as division and seed collection.
Then get busy at harvest time to preserve your produce yields and remember to start cool-season crops to enjoy in fall. Your garden will reward you with a fantastic display that’ll be the talk of the neighborhood!
What will you be sprucing up in your garden this season? Share with us in the comments below.
And for more easy ways to keep your garden in top form, check out the ideas in these guides next: