Zucchini and Summer Squash

Four varieties of summer squash were grown at the Horticulture Research Center (HRC) outside of Fort Collins, Colorado during the 2004 growing season. We direct-seeded (single seeded) the squash at 2′ in-row spacing in a single row on June 3rd into beds with 30″ centers, black plastic mulch, and one line of drip tape. Summer squash and zucchini harvest began on July 21st and continued through September 23rd. We harvested every other day. There was a significant hail storm on August 10th which affected the squash plants and caused a lull in production due to fruit damage and leaf loss. The plants recovered well (especially the patty pans which had more leaf cover to begin with), and the graphs below show the short-term effect on the yields. Below are photos, yield data, comments, and production graphs for each of the varieties.

A new pest for our area is the squash bug which promises to be very significant with regard to direct and indirect damage to the fruit, the plant, and potential yield and quality. This pest is difficult to control and naturally occuring biological control is not significant in our region. Powdery mildew was found on the zucchini and summer squash leaves; however, it is rarely a significant problem in our area until late in the season.

Photos	Variety	Yield Data	Comments
	Elite	extra fancy – 6.7 fruits/plant, 1.6 lbs./plant fancy – 7.5 fruits/plant, 3.0 lbs./plant large – 2.4 fruits/plant, 1.9 lbs./plant	hit hard by squash bugs, may have had to do with less water at far end of drip tape though, hit by hail hard since low leaf cover, n=85 plants, usually a very favored zucchini , the dark skin is favored in the West relative to the East, 48 days from seeding to harvest
	Goldrush	extra fancy – 7.6 fruits/plant, 1.6 lbs./plant fancy – 9.3 fruits/plant, 3.4 lbs./plant large – 2.2 fruits/plant, 1.5 lbs./plant	produced well, chefs like the straight yellow (better than crook neck), hit by hail hard since low leaf cover (n=54 plants), 48 days from seeding to harvest
	Starship Patty Pan	extra fancy – 13.3 fruits/plant, 2.5 lbs./plant fancy – 6.6 fruits/plant, 2.9 lbs./plant large – 4.4 fruits/plant, 5.2 lbs./plant	faired better in hail, heavier leaf cover, missed quite a few grew too large since green fruits were hard to spot, (n = 82 plants), 48 days from seeding to harvest
	Sunburst Patty Pan	extra fancy – 18.8 fruits/plant, 4.1 lbs./plant fancy – 6.7 fruits/plant, 2.6 lbs./plant large – 2.0 fruits/plant, 1.5 lbs./plant	faired better in hail, heavier leaf cover, easier to see yellow fruits, so didn’t miss harvesting them as much before they got too big, (n = 78 plants), 48 days from seeding to harvest

The dense patty pan squash plants (right) suffered less fruit damage during the August hail storm than the sparse straight squash plants (left).

Powdery mildew on squash leaf	Extra fancy, fancy, and large yellow squash

Production Graphs:

The following graphs show the pounds harvested per plant for the harvest dates over the season. Note that we had a large hail event on August 10, 2004 which reduced production temporarily.