The ideal time for planting flowers in Ohio is from late May to mid-October. So, if you're ready to add a splash of color to your landscaping and a sweet aroma to the air, we're about to enter the proverbial calendar year sweet spot for planting flowers in the Buckeye State.
Mid-April is usually a safe time to begin. Prepping the soil comes first. For your annual flowers to flourish, you want to properly prepare your soil. You may plant directly into the topsoil, or you can purchase heavier soil to help hold in moisture.
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.
Generally, the best time to start a garden in Ohio is between the last and first frost dates, or from the end of April to the middle of September, give or take a month.
March is a really good time to plant spring flowers, particularly if the last frosts have passed. If not, be sure to only put in frost-tolerant plants for now. Otherwise, wait until spring warmth is more consistent before putting in spring flowers.
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.
Anytime the ground is workable, meaning not frozen and the temperature is above freezing, you can install most perennials, shrubs and trees.
Ohio only has two USDA hardiness Zones, Zone 5 and Zone 6. Most of the state sits in Zone 6, but there are small groupings of Zone 5 mixed in.
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.
Plants and Planting
Pansy roots will not function when soil temperatures are below 45°F. When soil warms to about 65°F (about two to three weeks before frost-free date), cool tolerant plants can be planted, such as nemesia, diascia, snapdragons, alyssum, osteospermum, mimulus, lobelia and petunias.
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.
Look for cold-weather favorites like hardy mums, but be sure to seek out fiery ornamental peppers, ruffled flowering cabbages and kale, vibrant and fuzzy celosia, and classically reliable pansies and violas, as well.
Some cool-season annuals can tolerate soil temperatures as low as 45 degrees Fahrenheit; however, most cool-season annuals will grow best in soil temperatures at 65 degrees Fahrenheit or warmer.
You can transplant perennials anytime until the ground freezes in the fall, or wait to transplant them in the spring. Fall is an excellent time to transplant herbaceous perennials because your plants will then have three seasons to establish a good root system before hot summer weather sets in next year.
Flowers that come back up from their roots every year in the springtime are called “perennial” flowers. Some of the best perennial flowers to grow in a garden are peonies, daylilies, coneflowers, and hollyhocks.
Tender annuals — Tender annuals thrive in warm soil and warm air temperatures. They should only be planted once temperatures reach and stay above 55°F. They can be severely damaged or die if they are exposed to frost or temperatures below 32°F.
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.
Daffodils, Tulips, Hyacinths, and Alliums are all examples of spring flowers that need to be planted in the fall, in order, for them to bloom the following spring. From late September to early December fall bulbs can be planted.
The latest time to plant for most vegetables would be the second week in June with a short harvest time. If planting crops that mature within 50 days, you could plant those as late as the last week in June, but keep in mind the weather will be turning cooler, especially at night. Cool crops are best for late plantings.
Fall tends to produce more good planting days than Spring.
Another significant advantage during the Fall is that common garden pests and disease problems are less of a problem. Whether you are planting grasses, spring-blooming bulbs, perennials, trees or shrubs, they all will do great when planted in the Fall!