Crimson Yellow Watermelon Plant
The flesh of watermelons turning yellow is a natural mutation. In fact, the originator of our commercial variety, which comes from Africa, is a yellow to white fleshed fruit. The fruit has a sweeter, honey-like flavor as compared to red fleshed melons, but many of the same nutritional benefits.
Yellow watermelon plants need a full day of sun. Plant them away from buildings or tall plants that cast shade.
A rich, sandy loam will produce the healthiest yellow watermelon harvest. Add compost or manure to poor soils; in areas with clay soil, use raised beds with amended soil to improve drainage.
Keep soil moist but not soggy until fruits form. After fruits reach softball size, water only when the surface of the soil is dry. Overwatering can cause rapid growth that leads to cracking.
Temperature and Humidity
Yellow watermelons love hot weather, but if an extended hot spell in the triple digits is stressing plants, you can use shade cloth. Hot weather combined with high humidity can make plants susceptible to powdery mildew. Increase spacing to help air circulation and reduce fungal spores.
Chemical fertilizers aren't necessary to grow yellow watermelons. The slow, steady stream of nutrients from leaf mold, compost, or manure as a top dressing will increase soil fertility and tilth. Some commercial growers have been known to inject fruits with nitrogen fertilizer or other chemicals to stimulate large growth. Never attempt this with a watermelon you intend to eat.