11 Garden Tasks To Do In August

Depending on where you live, plants are winding down in the summer heat or gearing up for a fall flush. The average first frost in the U.S. ranges between mid-September and early November. For many of us, cool weather is a ways off, or so it seems, in August. That means there’s still much to enjoy in the summer garden. And plenty of good work to do.

While regular garden tasks are ongoing, they needn’t be all-consuming this August. Harvest abounds, and it’s time to capture ripening fruits and vegetables to save for later in the year. Saving seeds, too, from valuable crops and flowers is rewarding come spring. Propagating new plants and starting fall vegetables keeps the garden growing. And, of course, there’s weeding and pest maintenance, along with the fun of drying blooms and planning for autumn.

Remember to take a cue from resting plants. Late summer offers room for a little restorative lazing around. Sitting back and enjoying your garden is a well-deserved reward.

Preserve the Harvest

August means harvesting tomatoes, cucumbers, squash, eggplants, okra, peppers, and much more. Pumpkins and winter squash are well on their way to mature fruits. Peaches are entering their final fruiting, and apples are waiting for cooler temperatures. Raspberries and blackberries continually ripen on the vine.

Warm-season crops begin winding down as the bulk of their production is behind them. Continue to harvest regularly to promote late-season production. Protect tree and vine-ripening fruits from insects, birds, and small mammals with fruit nets, or pick them early, as they show color.

If you have a vegetable garden, the late-season flush of fruits means a harvest to devour, share, and preserve. Pickling and canning work well for most vegetables and fruits, like peaches and blackberries. You can also create homemade tomato pastes and sauces or raspberry jellies and jams.

If you need a simple and quick way to store the summer harvest, look to flash freezing. Freezing preserves vegetables and fruits for months at a time. Most will need blanching first to deactivate enzymes for preservation, lasting flavor, and to soften skin. You can also cover fruits and vegetables with water and freeze the entire block.

Trim, Clip, and Deadhead

While it’s not the time for heavy pruning, plants benefit from light trimming and shaping. Give hedges and topiaries a final haircut of the season. This will allow new growth tips to harden off before winter.

Trim herbs to promote a new flush of growth for the fall. Vigorous growers with sprawling stems and runners may be unruly. Now is an excellent time to get them back in shape, encouraging bushy forms. Use the herb harvest fresh, or dry the leaves and stems of favorites like thyme, oregano, rosemary, sage, and mint.

If you are growing summer squash like yellow, zucchini, and pattypan, pinch the tips of vining stems after enough fruits are set. This will prevent the plant’s energy from producing new growth and instead direct it to developing hearty fruits.

Clip away brown and crispy stems from annuals and perennials to revive the plant (or at least improve its appearance). Deadhead perennials and annuals regularly to promote further flowering. 

Cut brown, faded blooms off of hydrangeas to tidy up their appearance. Cut fresh blooms for drying (more on this below). Keep deadheading reblooming roses, too, but stop by Labor Day so that showy and valuable rose hips develop.

Adjust Fertilizer

With a high heat factor and slowing growth in August, considering your fertilizer schedule is helpful for lasting plant health.

Continue fertilizing annuals regularly, at least until they near the end of their life cycle. Stop fertilizing mid-to-late month for flowering shrubs like roses, depending on your climate. A good rule of thumb is to stop six to eight weeks before the anticipated first frost date. There’s no need to encourage new growth or rose blooms as plants slow and move toward winter dormancy.

Save Seeds

Most August garden tasks set the stage for next year, and what better way to do that than by saving seeds? With so many flowering perennials starting to go to seed, it’s useful to collect and store them for future seasons. The same goes for your heirloom or favorite food crops, especially if they’re hard to come by or from pass-along selections.

Seed saving is cost-effective and helps promote genetic diversity among our crops. Protecting genetic traits is a benefit of growing heirlooms, bred for their fruiting and growth characteristics.

To save seeds, collect them from flowers, fruits, or vegetables. Separate them from plant matter and rinse seeds from food crops if needed. Let them dry out completely. Store seeds in paper bags or envelopes in a cool, dark spot.

You may be creating new hybrids by saving seeds from cross-pollinated plants. Open pollination occurs commonly with peppers, tomatoes, and corn. 

Many hybrids, whether ornamental or edible, won’t come true from seed. Sticking with straight species rather than hybrids is best for collecting favorite performers reliably. 

Sow Cool Season Crops

August is ideal for looking ahead to fall and sowing initial crops. If you’re still in the throes of summer heat waves, hold off on direct-sowing cool-season varieties until fall. Start seeds indoors for transplanting when temperatures cool. August seeding includes parsley, lemon balm, collards, mustards, kale, radishes, peas, and turnips.

In warm climates (zone 7 and higher), you may still be able to fit in a final round of successional crops like squash, green beans, and corn. Make sure to choose varieties that are quick to mature so you can enjoy them before frost sets in. A benefit of late-season planting (other than the extended bounty) is that some pests, like the squash vine borer, are near the end of their active feeding cycles.

Propagate Herbs and Perennials

Propagation is another August garden task that ensures an abundant future. Divide irises and daylilies this month. You can plant new bulbs and other perennials, too. Fill in garden gaps with fresh, durable plants that will extend their interest into autumn. Hold off on major plantings until fall.

Take cuttings from perennials and herbs to propagate for spring planting. Soft stem cuttings rely on fresh, pliable growth. Late summer herbs and perennials for cuttings include salvia, caryopteris, lavender, verbena, and rosemary. Some herbs, like basil, can live in water indefinitely. Take snips of bushy herbs to enjoy in water on a windowsill through winter. 

Annuals, tropicals, and tender perennials that overwinter indoors are good propagation options. Keep newly rooted cuttings inside over the winter so they can move out in warm weather. Pelargonium, fuchsia, and coleus root in water or potting mix.

Cuttings taken in late summer may work for deciduous shrubs, including hydrangea, roses, and forsythia. For the best success, try taking cuttings early in the month. Over the winter, keep them in a greenhouse or protected area as they develop roots.

Patch Spotty Lawns

By late summer, grass may look a little weary in spots. All that summer fun may take its toll, or die back from insects, disease, water fluctuations, and intense sun. Whatever the cause of bald spots, adding seeds in patches is a simple fix.

Target the trouble spots for ease of application and to concentrate the seeds where they’re needed. Laying new sod or seeding an entire area is possible in August, with lots of regular moisture, but it’s not ideal in hot climates.

Mow grass regularly to a height of two to two and a half inches. This height keeps it looking lush and leafy, ensuring adequate moisture uptake and protecting tender shoots from the blazing sun. Stop using nitrogen fertilizers by mid-month.

Consider rethinking vast grassy areas by increasing bed space or implementing a turf alternative. Cover crop seeds can intermingle with existing grass. Or, create a plan for adding herbs and other soft ground covers by the season’s end.

Scout for Pests and Diseases

While it’s still the warm, active season for common pests, some slow down by mid-to-late August. Debris harbors pests and diseases, so clean up fallen leaves and petals around plants to lessen their habitat. Clearing debris creates a fresh, clean look as an added incentive.

Water plants and lawns consistently to avoid drastic fluctuations. Changes in moisture, coupled with hot conditions, make plants susceptible to pest and disease damage. Water deeply, rather than frequently and shallowly, to support healthy roots. Avoid overwatering, which leads to stress and fungal issues.

Be on the lookout for bagworms and webworms, which stop feeding and attach to stems to form webs. Manually remove the pests.

Spider mites may be an issue in hot, dry conditions. Spray them with a hose blast to knock them off plants.

If you’re growing cucurbits, continue to scout for squash vine borers. The larvae (caterpillars feeding on the squash stems’ interior) will stop feeding and exit the plants. They’ll burrow into the soil to overwinter until spring.

Pluck Weeds

We know keeping up with weeds is an ongoing garden task, but it’s especially important in August. If you pull weeds before they go to seed at this time of year, it significantly helps future plantings. 

Removing the seed heads (and roots while we’re at it) hinders the spread of a rapidly multiplying weed population. Take care not to drop accidentally and scatter seeds as you pull the weeds. Dropping seeds happens, but minimizing drop means fewer pesky weeds.

Dry Flowers 

Many perennials and flowering shrubs produce blooms that dry beautifully for floral arrangements that last well beyond summer. Dried blooms capture charming vintage tones and nostalgic qualities. Clip fresh blooms early in the day, after the morning dew dries. 

Hanging flowers is an easy way to preserve them. Remove leaves and bundle stems in small groups. Tie stems with soft twine and suspend them upside down. Use a clothespin attached to a hanging line or tie strings to a rod to hold the bundles. Leave the blooms in a dry, dim space. Cool or humid settings prolong the drying time for flower heads.

Flowers may take a few weeks to dry completely. When fully dry, they will have stiff blooms and crisp stems that snap easily.

For hydrangeas, cut blooms fresh or let them dry on the stem. In late summer or early fall, the blooms become papery and stiff. The color will transition to dusky pink and green when they’re perfect for clipping.

Plan for Next Season

Planning for the next season is a fun break from regular maintenance. It gives us a breather from the hot weather and allows creative inspiration for the fall, winter, and beyond. Assess what’s thriving, what to divide, and what you might like to arrange differently. Consider structural additions like raised beds and vertical supports to add dimension.

Do a simple site analysis or create a landscape plan for improvements. The analysis and plan will be handy come fall, prime for adding and moving plants.

Plant Fall Shrubs and Trees

Consider upcoming additions, like trees and shrubs. Fall is ideal for planting trees, shrubs, and perennials. Plan for maturity, ensuring plenty of space for fully-grown specimens.

Order Bulbs

It’s a good idea to source spring flowering bulbs this month. Fall is the best time to plant spring bulbs; ordering them early ensures a good selection. Look for tulips, daffodils, and crocus for a showy display. 

Plant the bulbs in the fall when soil temperatures reach 40-50°F (4-10°C). Leave them be until the burst of blooms. Plant en masse if you have the space and budget. The more bulbs, the better for impact, but even a handful in a container is a lovely welcome to spring.