While spring may be the most common season to tend to your flower garden, that doesn't mean you can't grow something beautiful this fall! August is often the perfect time to start planting because it encourages root growth in the soil before things start freezing, giving your garden a head start for the spring.
Even if you didn't get a spring garden planted, there is still time, late summer, to plant vegetables and harvest them before the first frost. A late summer garden means you can harvest fresh produce well into fall and sometimes even into winter.
Generally speaking, spring-flowering bulbs should be planted in the fall (a few weeks before first frost), while summer-flowering bulbs should be planted in the spring (a few weeks after last frost).
The hardiest of flowers can be planted as soon as the soil in your garden can be worked, even if it's several weeks before the last frost of the season. For half-hardy flowers, hold off until a couple weeks before the final frost, and for tender flowers, plant when there's no chance of frost for the rest of the season.
In fact, many plants — such as spring bulbs and perennials — need to be planted in the late summer or early fall months, depending on your zone, in order to generate enough energy to bloom in the spring. Not to mention, it's never too late to add some colorful annuals to your outdoor space!
Answer: Late summer (late August to mid-September) is an excellent time to plant many perennials. It is also a good time to move or divide perennials, such as peony, daylily, garden phlox, and oriental poppy.
Gardening in the fall provides a longer period with more 'good' days, as compared to the often tumultuous spring season. Plus, if you plant in fall you'll end up ahead of the game and won't have to rush to get everything done after winter. In fact, a good strategy is to plant perennials when you plant your fall bulbs.
Most flowers should be planted after your region's last frost date. Planting flowers in spring is the most popular time, but perennials do fine if planted in early fall in the North and late fall in the South.
While you can plant a late planting to the first frost date, it's always best to allow as much growing time as possible. If you missed the spring planting, then calculate which vegetables you can grow now and still have a harvest before the first frost.
Mid-August to mid-October is an ideal time of year to plant new trees, though, that time frame can be stretched into November and December. To be 100% sure, measure soil temperature early in the morning for a few, consecutive days. If your soil is consistently 50° F or higher, you're good to plant.
Although each plant's needs may vary and some will be more winter-hardy than others, in general about a month before the last fall frost is sufficient in giving the plant enough time to establish itself and take root.
Late summer planting
Choose quick-maturing crops. Spinach, lettuce and greens, beets, carrots, peas, and beans can be sown now. Most seeds will readily germinate in the garden now because the soil holds heat well into autumn; warm soil (in the 70°s) is ideal for seed starting, as long as the weather is not too hot.
Plants that thrive in fall weather include: carrots, beets, broccoli, Swiss chard, kale and all kinds of salad and Asian greens. Choose disease-resistant varieties that mature quickly. All can be direct-sown into the garden, though broccoli can also be started indoors under lights or in a greenhouse.
Some fast growing fall crops like lettuce and radishes can be planted into late September, but many desirable fall crops like broccoli and carrots need several months of prime-growing conditions to mature before frost and low light levels set in. When in doubt, plant your fall crops a little early.
Vegetables that can be planted in August include leafy greens such as lettuce, spinach, collards, kale and mustard. Radishes, turnips, beets and carrots can all be started from seeds in August.
When to Plant Marigolds. Young French and signet marigolds can be planted from spring through midsummer, but the tall African marigolds are best planted right away in the spring (after danger of frost has passed) because they are slower to mature and produce flowers.
The general rule of thumb is that most plants freeze when temperatures remain at 28°F for five hours. Of course, there are exceptions to this rule. Seedlings, with their tender new leaves, often give up the ghost when temperatures dip to 32-33°F. Tropical plants have differing low-temperature thresholds.
There's no question that flowers need protection from frost and freezing temperatures. Many flowering plants won't survive very long once temperatures dip below freezing and will typically die within a few hours once the mercury hits 28 degrees Fahrenheit.
The primary reason a garden usually fails is water. If you water too much or don't water enough, your plants will die. Other common mistakes include setting out tender seedlings without a hardening-off period. Young plants need a short acclimation period before meeting the bright sun.
And some of the annuals that are normally considered spring flowers will flourish in the cooler fall weather, if only for a short time. Mums, specifically florists' or garden mums, have become the go-to plants for a fall garden.
Plants like chrysanthemums, nasturtiums and asters are wonderful choices for seasonal planting arrangements. While perennials that will survive the winter are great choices, autumn is also a great time to explore new ideas will short-season annuals too.
For the plants, fall is a fine time for a flower-bed makeover. Cooler temperatures slow water loss from leaves, so plants can better tolerate being ripped out of the ground and roughed up before having their roots nestled back into dirt.
Tip. Mid- to late-August is often an excellent time to plant fall flowers, as long as the weather isn't still so hot that the plants will suffer heat stress. But don't wait too late to plant, or you'll have a very short window to enjoy your flowers. Check the growing requirements for each plant.
Dahlias are an obvious choice when it comes to what to plant in August, as they will flower right up to the first frosts and several varieties bring added interest with bronze foliage. You can also rely on long-blooming salvias, astilbes, sunny rudbeckias and gaillardias, asters, sedums and heleniums.