Planting Season

• Watermelon is commonly one of the last seeds planted by most gardeners. Melons and many of the other vine vegetables have no tolerance for frost and should not be planted until after the last possible frost of spring. The average date of the last frost in the area is available from county extension offices or local garden clubs. Adjust the date based on local forecasts for the current year. Don't plant watermelons on the average date of the last spring frost if the forecast calls for colder-than-normal temperatures.
  
  

Soil Temperatures

• Standard watermelon variety seeds germinate in soil of at least 55 degrees F. Measure the temperature at the standard planting depth of about 2 inches. Ideally, daytime air temperatures should be about 80 degrees F, with nighttime lows of about 70 degrees F, while the watermelon seedling grows. An exception to these standards are the seeds for the "seedless" watermelon varieties. These require soil temperatures of about 80 degrees F, commonly not attainable in most gardens in the spring.
  
  

Starting Indoors

• Start standard watermelon seeds in small peat pots about three weeks before the anticipated date of the last frost. Keep the pots in a sunny location at room temperature. The best option for starting the seedless watermelon plants is placing seeds in a peat pot. Place the pot in a sunny location with temperatures of about 80 degrees F. Transplant either type of watermelon into the garden after the last frost of the spring. Do not remove the plant from the pot but, rather, plant the entire pot in the garden.
  
  

Protecting the Plants

• Sometimes the weather changes and what was thought to be the last frost of the spring turns into the second-to-the-last frost of the spring. Gardeners can cover the plants with any of the commercial products, such as Hot Kaps, designed to protect garden plants from low temperatures. Another option is to place plastic sheeting or other flexible material over the plants temporarily during any late cold snaps.