Hello Mid-Ohio Valley farmers and gardeners!

Things heat up in the valley as we head toward Independence Day this Saturday. Be careful out there, stay hydrated and don’t spend too much time in the summer heat.

As we celebrate America’s 250th birthday, I want to present a short history on Thomas Jefferson and the Declaration of Independence.

At the 2nd Continental Congress in Philadelphia, it had not officially been voted on to break away from Great Britain and declare Independence. Many patriots felt someone needed to articulate why the Americans were breaking away to sway more members to vote for independence.

Thomas Jefferson had the fewest enemies in Congress and was the best writer, not to mention the chair of the committee to draft a declaration. On June 11, 1776, Congress appointed a committee including Jefferson (Virginia), Roger Sherman (Connecticut), Benjamin Franklin (Pennsylvania), Robert R. Livingston (New York), and John Adams (Massachusetts).

Written in June 1776, Thomas Jefferson’s draft of the Declaration of Independence, included 86 changes made later by John Adams, Ben Franklin, other members of the committee and by Congress.

The Declaration borrowed heavily from the Virginia Declaration of Rights by George Mason. The final text was adopted by Congress on the morning of July 4, 1776.

The initial print was sent to George Washington by John Hancock, president of the Continental Congress on July 6, 1776. General Washington had the Declaration read to his assembled troops in New York on July 9. Later that night the Americans destroyed a bronze statue of Great Britain’s King George III.

This week let’s talk about watermelon (Citrullus lanatus), a member of the cucumber family that originated from the warm climes of tropical Africa. One of the true joys of summer is eating fresh watermelon on a hot day.

Considering it is 92% water, watermelon can help rehydrate the body. It contains a variety of nutrients, including potassium, magnesium, and vitamins A and C. It’s also relatively low in calories, containing just 46 per cup.

A few interesting facts about watermelon. Seeds and paintings of the watermelon were found in King Tut’s tomb as a gift for his long journey to the afterlife. Watermelons spread from Africa to China in the 10th Century and today, China grows more than any other country. The U.S. ranks fourth in the world for watermelon production. Top growing states include California, Arizona, Texas, Florida and Georgia.

Watermelon is fun to grow (especially for kids), including the traditional seeded type with red flesh in addition to the yellow and orange fleshed and many seedless varieties. Summer is not summer unless you grill out with all the fixings, including watermelon.

Be sure to consider watermelon need lots of space and has a long growing season. The growing area required for watermelon is in excess of 18 to 24 square feet per plant. Smaller varieties of watermelon have a shorter growing season of about 70-75 days such as Sugar Baby.

Watermelons love the heat and thrive in warm soils, so wait to transplant them until the danger of frost has passed and days are consistently sunny and warm. The soil temperature should reach 65-70 degrees Fahrenheit before planting in the garden.

When planting, gardeners start seeds indoors and plant transplants, but if you direct seed, plant in hills spaced 6 feet apart. Sow four to five seeds per hill at a depth of about 1 inch. Thin the seedlings to two per hill a week after they have germinated. Compared to other plants, you need more space between rows. Allow at least 7 feet between rows.

Watermelons need a well-drained soil that receives 8 to 10 hours of sunlight per day. They thrive in warm soils, so wait to transplant them until the danger of frost has passed and days are consistently sunny and warm. The soil temperature should reach 65-70°F before planting watermelon in the garden. Avoid excess nitrogen, which can result in hollow heart.

The soil pH should be between 6.0 and 7.0 for best growth. For proper fertilization, a soil test is always recommended (which is free in West Virginia from the WVU Soils Lab).

Adding organic matter such as compost or well-rotted manure and incorporating in the soil can improve fertility. A complete fertilizer such as 10-10-10 or 13-13-13 can be applied at the rate of 3 pounds per 100 square feet of garden. Spade or till the soil to a depth of at least 6 to 8 inches and level the soil with a rake.

Watermelons generally take 70-90 days to mature and are grouped according to fruit shape, rind color or pattern, and size. These groups are often named for a popular variety with those characteristics. For example, oblong melons with dark stripes on a light background weighing 25 to 35 pounds are called “Jubilee” types after the popular Jubilee variety.

“Crimson Sweet” type are round melons weighing 20 to 30 pounds with a striped rind and round watermelons weighing 10 pounds or less are referred to as icebox melons (they fit nicely into the fridge).

There are hundreds of varieties to choose from. Some Standard varieties are “Charleston Grey,” “Crimson Sweet,” “Jubilee,” “Sweet Favorite,” and “AU-Producer.” Some recommended early varieties include “Bush Sugar Baby,” “Golden Crown,” “Sugar Baby,” and “Yellow Baby.” “Cotton Candy,” “Honey Heart,” “King of Hearts” are some seedless varieties.

Everyone loves seedless watermelon! However, it was not until about 1990 that seedless watermelons began to gain popularity. Today they dominate the market.

There are a few things you need to know about the seedless varieties, called “triploids.” Seedless watermelons are sterile hybrids that produce no fully developed seeds in the fruit. You may see some immature edible white seeds called pips.

The seeds are more expensive, due to the increased cost of producing them. Standard watermelons with seeds are “diploid,” meaning they have two sets of chromosomes, one set from each parent.

Nurseries produce a seedless melon by treating a parent plant with colchicine (a chemical derived from autumn crocus) causing four sets of chromosomes to be developed. The resulting “tetraploid” plant is crossed with a regular “diploid” plant to create a “triploid” plant containing three sets of chromosomes.  

Extension does not recommend direct seeding seedless (triploid) varieties. Seedless watermelon should be started as transplants. The seeds germinate weakly due to a thicker seed coat and do not respond well to soil and temperature fluctuations.

Furthermore, a standard seeded watermelon variety must be grown in the garden along with a seedless variety to provide pollen for fertilization and fruit formation.

Watermelon and other cucurbits (cucumbers, squash, and pumpkin) have separate male and female flowers, so pollination by honeybees is important for large, quality fruit. Pollen must be transferred from the male flower to the female flower for seed set and fruit development. Poorly pollinated flowers either abort (called blossom drop) or produce misshapen fruit.

Excessive vine growth and few fruit are usually the result of an over-application of nitrogen fertilizer or by planting too close. Insect problems are usually critical only in the seedling or early growth stage. Cucumber beetles, squash bugs, and aphids are the most harmful insect pests.

Many gardeners ask, “How do I know when to harvest the watermelons?” Watermelons should be picked at full maturity because they do not continue to ripen after being removed from the vine. The tendril nearest the point on the vine where fruit stem attaches should be brown or dead.

From the time of fruit set, it takes approximately 35 days to fruit ripening. The following are a few rules of thumb to help determine if your watermelon is ready for harvest. If the fruit looks to be expected size, the tendril closest to the fruit turns brown, the skin color loses its gloss and becomes dull in color, and the bottom of the fruit has a large white to cream color oval spot it is ready to pick. Enjoy!

Contact me with questions at the WVU Extension Office at 304-424-1960 or at jj.barrett@mail.wvu.edu. Good Luck and until next time, happy gardening!