Why when they were acorn squash seeds ?

Asked September 28, 2019, 11:53 AM EDT

These squash all grew on the same vine. Some are pumpkin shaped. Some are elongated. My question is why because they were acorn squash seeds from a squash that I saved the seeds from last year. 100% was an acorn. No other squash or anything in that family was planted anywhere near them this year or in the past. Interested to hear any thoughts. Thank you !


Beaver County Pennsylvania

1 Response

Hello, and thanks for using the Ask an Expert System.

To understand what is going on with your squash plants you need to understand how squash plants reproduce.

Squashes, along with all cucurbits, are cross-pollinated. This means that they have both distinct male and distinct female flowers. They rely on insects to pollinate them. Because of this, it is easy for two varieties of squash to cross-pollinate and produce seeds that will not grow out true to their parent. Winter squash may cross-pollinate with summer squash, zucchini, and pumpkins as they are all the same species. However, any crossing will not affect that year’s fruit, only the seeds.

The acorn squash you planted last year grew from commercially produced seeds that were pollinated in a closed environment. Thus, all the last year seed were pure acorn squash, and produced a fruit that was acorn squash. However last year’s female flowers were open pollinated and could have been pollinated by wind, bees or other insects. The pollen might have come from pumpkins, gourds, zucchini, or any other related cucurbits. Now the seed is no longer acorn squash, but a hybrid, a mutt. These seeds can produce plants with fruit that is quite different than produced on the original hybrid parent. You cannot be sure how the fruit will turn out. Your vine simply produced highly variable fruits as shown in your photos.

It is possible to save seed from acorn squash, but you must control the pollination. It is easer to purchase a packet of commercial seeds that are pollinated to produce consistent results.

If you have additional questions, I suggest that you contact the Beaver County Penn State Extension “Greenline.” The Greenline is a free service offered through the Penn State Extension office to help Beaver County residents with questions and concerns about flowers, vegetables, trees, shrubs, lawns, household insect and animal pests, and more.

Beaver County Penn State Extension