Yellow Squash

What it is. Yellow squash includes the straightneck and crookneck types of summer squash, all from the Cucurbita pepo species. It is a very tender, warm-season annual vegetable. It comes from the same parent plant as many courgettes, zucchini, and pumpkins, and it has yellow flowers with male and female blooms on one plant.

When and how to sow. Sow the seed outdoors after the last chance of frost has passed. Squash seeds do not germinate well in cold soil, so wait for the soil to warm. Plant the seed ½ inch (1.3 cm) deep and 4 to 6 inches (10 to 15 cm) apart in rows about 3 feet (90 cm) apart. Once seedlings have one or two true leaves, thin them to 12 to 15 inches (30 to 38 cm) apart. Seed is easy to sow, especially when the soil is warm.

Transplants and sunlight. You can also start seeds indoors in 3-inch (8 cm) containers about 3 weeks before planting time. Handle transplants gently and disturb the roots as little as possible. Choose a site in full sun, which means at least 6 hours of direct light a day; the plant prefers 8 to 10 hours a day.

Watering. Keep moisture steady and water in the morning so leaves dry before evening. Water enough to moisten the soil about 6 inches (15 cm) deep, because light watering encourages shallow roots.

Soil and mulch. Work compost into the soil before planting. Mulch with 2 to 3 inches (5 to 8 cm) of grass clippings, pine straw, or leaves to slow soil drying.

Feeding. Soil pH should be kept between 6.0 and 6.5. Too much nitrogen encourages excess vine growth and reduces fruit growth.

Pollination. Bees carry pollen to the female flowers, and poor pollination can result in little or misshapen fruit. Male flowers appear one to two weeks before the females. If fruit set is poor, try hand pollination. Avoid pesticides during bloom to protect pollinators.

Insect pests. Aphids, squash bugs, cucumber beetles, pickleworms, and squash vine borers are common problems. Slugs, aphids, and beetles are also listed as common pests. Aphids can spread viruses to the plants, and squash vine borers can cause the whole plant to collapse. Planting early helps, because borers and pickleworms are worse later in the season.

Diseases. Powdery mildew is a common fungal disease on the leaves, and viruses are also common. Blossom-end rot shows as a dark, dry rot at the blossom end of the fruit and is linked to low calcium in the fruit. Mulching and avoiding excess nitrogen or potash help prevent it.

When to pick. Pick crookneck and straightneck types when the fruit is 1½ to 2 inches (4 to 5 cm) across. Yellow crookneck fruit is picked at 4 to 7 inches (10 to 18 cm) long. The fruit should have a rind that is easy to puncture with a fingernail.

Timing and frequency. The crop can be harvested about 55 days after planting, while it takes 50 to 65 days from transplant. Harvest often, because leaving large fruit on the plant slows new fruit; harvesting frequently also keeps fruit from becoming too large and less tasty.

Storing. Keep harvested squash at 32 to 50 °F (0 to 10 °C) and about 90% humidity, where it keeps for roughly 5 to 14 days. In the kitchen, it is suggested to store it in a plastic bag in the refrigerator for up to 1 week.

Pets. Yellow squash is listed as non-toxic for cats and dogs.

Pollinators. Use insecticides late in the evening so you don’t kill bees.