Yellow summer squash is a versatile vegetable that can be oven roasted, grilled, sauteed, pureed and even deep fried. Although it's a member of the gourd family, the summer squash is designed to be picked and eaten before the outer rind hardens. In addition to the many uses of the vegetable itself, the squash blossom is also popular in appetizers and salads. Whether you want enough to feed the family or the neighborhood, here's what you need to know about growing a great crop of summer squash in the northwest states.
Choose a location that will provide full sunlight and soil that has adequate drainage. There is potential for cross pollination with other types of squash, including pumpkins and acorn squash. To prevent this, plant summer squash in a location where it cannot come into contact with the other squash plants.
Prepare the soil when the ground temperature reaches at least 60 degrees Fahrenheit, typically from mid-April to early May in the northwest states. Spread a layer of compost and work it in to a depth of at least 6 to 8 inches. Form 8- to 10-inch mounds, leaving 4 to 8 feet between each, for the desired amount of summer squash plants. Typically, you will grow one or two plants per mound. Work 1 to 2 tablespoons of complete fertilizer with a concentration of 4-8-5 or 6-10-10 in to each mound before planting the seeds.
Plant four to six summer squash seeds per mound, only after the last chance of frost has passed. Plant seeds in a circle, leaving a 5-inch space between seeds. Once the seeds have sprouted and have two or three sets of leaves, thin out weaker plants, leaving two to three strong plants per mound.
Apply a layer of mulch around the base of each summer squash plant, once the plants have established and the ground has warmed. This will help maintain proper ground temperature and moisture levels.
Water yellow summer squash plants in the morning or early afternoon hours. The plants need at least 1 inch of water per week. Using a soaker hose will allow the plants to be watered thoroughly enough to reach the deep root system.
Fertilize summer squash plants after blossoming occurs, and again three weeks later. Light, sandy soils will need more nitrogen than soil that is well balanced. Avoid applying too much nitrogen, however, as this will encourage the plant to produce too much vine and not enough fruit.