Sweet potatoes are a tropical crop perfectly suited to Florida’s long, warm growing seasons, allowing them to thrive where many other vegetables struggle with the summer heat. Unlike the common potato, the sweet potato is a true storage root that requires specific conditions for growth and post-harvest handling to achieve peak flavor. Knowing when to dig the roots is only the first step in a process that determines the quality and storage life of your harvest. Because Florida generally lacks the hard frost that signals harvest time in northern climates, gardeners must rely on a different set of indicators for a successful yield.
Determining the Harvest Window in Florida
The primary method for determining the harvest time in Florida is calculating the days that have passed since planting the slips. Most sweet potato varieties mature between 90 and 120 days after the slips, or vine cuttings, are transplanted into the soil. Planting usually occurs from March through June, to allow the plants to take full advantage of the warmest months. This planting schedule places the expected harvest window in the late summer or early fall, generally from August to October.
Sweet potatoes continue to grow and size up until they are harvested. Since the threat of frost is often absent, the “days to maturity” guideline is the most reliable calculation for timing your harvest for optimal size and flavor. Growers who wait longer than 120 days may achieve a higher total yield with larger roots, but they also risk the roots becoming overly large or splitting, which can affect quality.
Visual Indicators of Maturity
While the calendar provides a good estimate, the plant itself offers visual clues that the storage roots are ready to be dug up. The most common sign is the yellowing of the leaves and vines. This change signals that the plant is redirecting its energy and stored starches down to the roots below the soil line.
This yellowing is not always a complete die-back, especially in a subtropical climate where the vines can continue to grow indefinitely. Instead of waiting for the entire plant to collapse, a more definitive test is to “sample” a small hill of the plant before a full harvest. Gently digging a small area near the main stem allows you to check the size and maturity of the roots without severely disturbing the entire crop. If the exposed roots have reached a desirable size, the entire patch can be harvested; if they are still too small, simply cover them back up and wait another week or two.
Safe Digging Techniques
The skin of a freshly harvested sweet potato is thin and extremely delicate, making careful digging a priority to prevent damage that can lead to rot. The first step is to cut the extensive vines back, leaving a short stub of about six inches from the main stem to clear the area and make the roots easier to locate. This also helps eliminate hiding places for pests like the sweet potato weevil, which can damage the roots.
To avoid slicing or bruising the roots, you should begin digging at least 18 inches away from where the main stem enters the soil. A garden fork is preferable to a shovel for lifting the roots, as its tines are less likely to puncture the sweet potatoes. Once the soil is loosened, gently lift the roots by hand, handling them with care to prevent nicks and scrapes that will compromise their storage life. Only brush off the excess, loose soil; do not wash the roots, as moisture encourages spoilage before the curing process begins.
Curing and Preparing Sweet Potatoes for Storage
Curing is the most important step for transforming a fresh sweet potato into a sweet, long-storing vegetable. This process involves exposing the roots to high heat and humidity to heal any wounds and convert starches into sugars. Immediate post-harvest curing is necessary to toughen the skin and reduce the chance of rot during storage.
The ideal conditions for curing are a temperature of 80 to 85 degrees Fahrenheit and a high relative humidity of 85 to 90 percent, maintained for a period of four to 14 days. In Florida’s warm climate, a shaded, humid outdoor area can often work, but consistent temperature control is key for a successful cure. Without proper curing, the sweet potatoes will lack sweetness and will not store for more than a few weeks. After the curing period is complete, the roots should be moved to a cooler, dark location, ideally kept around 55 to 60 degrees Fahrenheit, and never below 50 degrees, as they are sensitive to chilling injury.