Your guide to what, and when, to plant in the Lowcountry

Dwarf French marigolds are useful rotation plants in annual beds and vegetable gardens, since they suppress root-knot nematodes. To achieve pest control, they must be planted in solid masses.

Provided/Anthony Keinath

When I moved to Charleston from the Midwest, adjusting to the long fall growing season was easy. Some summer bloomers, like trailing lantana or salvias, simply continue blooming until frost, which can come as late as December instead of as early as September.

Adjusting to a gardening season that starts in January was harder. It took several years to realize how early some plants, particularly vegetables, should be planted in the spring for the best growth.

Seasonal temperatures dictate the best times for planting most annuals, which are plants that live only one growing season or year. The idea is to match their growth period with the weather that best suits them.

Growing conditions in spring and fall are opposites. The spring season starts cool, with slow plant growth, and ends warm. The fall gardening season starts warm with rapid growth but ends cool.

Planting too early in the spring risks cold damage, while planting too late in the spring may lower yields of vegetables that "can't take the heat."

Heat causes lettuce and radishes to flower, making them bitter. Pea pods are stunted in the heat. Tomatoes and peppers set neither flowers nor fruit when night temperatures are above 75 degrees.

Planting vegetables too late in the fall means crops won't mature before frost. For example, once temperatures drop below 60 degrees at night, melons stop growing.

The planting times given here are the earliest recommended dates. If you are like me and always seem to be behind schedule in the garden, you can still plant up to two weeks later.

This list includes many of my favorite annual vegetables and flowers that can be grown reliably in the Lowcountry.

For more information, see Clemson's Home Garden Information Center,

Seed green, snap or English peas. My favorite variety is Super Sugar Snap, an edible-pod and heat-tolerant pea that gets 5 feet tall.

Start seeding cool-season vegetables. Early sowing is essential for spinach, which quickly goes to seed when the weather warms up. Choose heat-tolerant varieties to keep spinach productive.

Set out purchased collard and cabbage plants and alyssum seedlings and sow broccoli seed.

Wait until early to mid-March to transplant broccoli and cauliflower, so a late cold snap won't trigger premature heading, before plants have grown large enough to make an edible-sized head.

Transplant tomato, muskmelon and watermelon plants so tomato and muskmelon will be ready by early to mid-June and watermelon by late June.

Seed cucumber, squash, beans, dill and fennel directly in the ground, or transplant cucumber and squash plants after April 1. Butternut and acorn winter squash grow better here when planted in spring than in summer.

Plant summer annual flowers such as vinca, marigold, zinnia, ageratum, pentas and angelonia. These annuals may or may not survive all summer. (Last summer was the first time my marigolds bloomed until frost.)

Transplant basil seedlings outdoors.

Plant pumpkin seeds to harvest fruit in early October. If you have the space, try Aladdin, a vigorous variety with some tolerance to heat and disease that produces 15-pound fruit.

Set out tomato and pepper transplants. If pepper plants from the spring garden look healthy, leave them over the summer and trim them back for fresh growth and larger harvests all fall.

Seed powdery mildew-resistant varieties of summer squash and zucchini. Because downy mildew is sure to attack fall cucumbers, don't bother seeding them unless you plan to spray with conventional fungicides. No organic products work.

Seed alyssum, which grows quickly from seed.

Seed cool-season vegetables, such as lettuce, leafy brassicas (collard, kale, mustard, turnips, and bok choy), radish, spinach, beet, chard, and carrots. Delay seeding spinach until Oct. 1.

Plant garlic cloves and onion sets for harvest in late June when tops yellow and die back.

Begin planting winter annual flowers, especially pansies and snapdragons, so they have time to establish before cold weather. The most cold-tolerant winter annuals such as foxglove, wallflower, dusty miller and parsley, can be planted until Dec. 1. Note that plant selection is best before Thanksgiving. By then, garden centers clear out fall plants to make room for Christmas greenery.

Anthony Keinath is professor of plant pathology at the Clemson Coastal Research & Education Center in Charleston. His expertise is in diseases of vegetables. He is also an avid gardener. Contact him at