Melon quality (taste, aroma, texture) is better when the sugar content of the fruit is high. Sweet melons need lots of sun, warm temperatures, sufficient water and freedom from diseases and pests. Sugar content is rated on the Brix scale, which measures the percentage of solids (everything that is not water) in the juice extracted from the fruit. These solids not only include sugars, but also amino acids, proteins, minerals and vitamins. In other words, sweeter fruits also have more complex flavors and a better nutritional profile.
The Brix index, often abbreviated to “Bx”, is the result of the interaction between genetics, climatic conditions, soil conditions and maturity. Here are some helpful tips on how to leverage these strengths to grow the sweetest melons possible.
1) Choose the sweetest varieties
Some melons are naturally sweeter than others, and this is purely due to genetic makeup. Some seed suppliers list the average Brix value of their melon, but for many common varieties this information is easily obtained with a quick Internet search. A Brix value of 12 is considered pleasantly sweet, 14 very sweet, and 16 too sweet.
2) Sow early in the season.
A long, warm growing season is necessary for optimal maturation and therefore good sugar content. Start germinating melon seeds indoors in 10cm pots at least six weeks before the average last frost date in your area, so that the seedlings are already well established when warm weather arrives. If you plant seedlings outdoors in cold weather, they will stop growing, so wait a few weeks after the average last frost date to do so, or until night temperatures are consistently above 60°F.
3) Find your warmest microclimate
Heat strips sugars from melons, so plant them in a location that warms up in early spring and stays warm until late September. The south side of a fence or wall is ideal, as the structure absorbs the sun’s heat and light and reflects it onto the melons. Placing melons near a sunny brick patio or other paved surface also helps create a warm microclimate for these tropical plants. These measures are not necessary in the south of France, but in colder climates melons need all the help they can get to reach optimal ripeness.
4) Make the most of the sun’s rays
You can’t do anything to change the climate you live in or the amount of sun in your yard, but there are some tips for making the most of the heat available in each location. An essential tip is to cover the ground of melon trees with black plastic gardening sheets, which retain heat like an asphalt surface. You can also place clear plastic or clear fabric covers over melon trees to create a mini-greenhouse. These sheets should be removed in early summer, when the plants begin to flower, so that insects can pollinate the flowers. Cover the beds again at the end of summer to ensure optimal maturation in the cold.
5) Don’t overcrowd melon plants
Melons grow on large vines and do not ripen effectively when grown in confined spaces. Seedlings are usually planted in piles (three per pile) 60 cm apart in 180 cm rows. Reduce the number of fruits to three melons per vine, in order to recover more nutrients (and therefore sugars) in each melon. If space is an issue, build a sturdy trellis and place the melons on the south side of the trellis: this saves space in the bed, but also puts the fruit in better contact with the warm rays of the sun.
6) Sugar content starts in the soil
Sugar is produced in the leaves through photosynthesis and then sent to the fruits. The more abundant the leaf growth, the higher the Brix index. To encourage vigorous growth, mix 4 to 6 inches of composted manure into your melon beds before planting. Then add a