Edited 8/6/2022: I may have been somewhat hasty in my original post. I removed the insect barrier. As expected, I am now getting full-sized summer squash. But the largest of these, so far, has only a vestige of seeds. For all intents and purposes, it’s seedless. To me, this suggests that, at some point, these squash plants did indeed begin producing full-sized fruit despite a lack of pollination. Perhaps they have to produce a handful of tiny ones first, before they give up on getting pollinated and begin producing full-sized parthenocarpic fruit.
The original post follows.
One tiny detail. The seed packets for parthenocarpic squash failed to mention one tiny, little detail.
Looking on the bright side, you know how summer squash will go from small to gigantic before you know it? One day they’re barely edible, three days later they’re barely liftable?
Or how you can be inundated with zucchini, to the point where you have to keep dreaming up new ways to cook it? Where you start figuring out ways to hide it in food, so that your family won’t object.
The good news is, parthenocarpic squash have both of those problems licked.
They’re tiny. Unless a miracle happens, my parthenocarpic summer squash are going to weigh in somewhere around one ounce each.
If you’re interested, read on. Or just check the photos below.
Background and results.
I had a terrible time with squash vine borers over the past two seasons. After endless rounds of spraying to keep them off my squash, I got the clever idea of growing squash in an insect-proof enclosure. Like so:
The only problem is that once that’s closed up, the bees can’t pollinate the squash blossoms. Hence the need to grow parthenocarpic varieties, that is, varieties of summer squash that will set fruit without pollination. The theory is discussed in Post G22-013.
And now I can attest that they will, in fact, set fruit without pollination. But I’m going to add a significant detail that, somehow, none of the seed sellers bothered to mention.
Yes, they set squash without pollination. Little, tiny squash.
If a miracle occurs, I’ll come back and edit this. But I’ve been eyeing these squash for more than a week now. They aren’t getting much bigger. And now, at the base, they are developing the deep golden color of mature yellow straight-neck summer squash. By all appearances, this is as big as they’re going to get.
Looks like the mature size will be 4 — oh, let’s be generous — 4.5 inches. The currency in the picture is for scale, with that bill being just slightly over 6 inches long.
And make no doubt about it — that’s a full-sized summer squash plant. And it’s producing squash that are roughly the size of your middle finger.
Which I now give to these plants. These are full-sized summer squash plants. As is their habit, they are sprawling all over and beyond that garden bed. And for all that space, and all that leaf area, if I’m lucky, I’ll get a few dozen little baby squash.
At the end of the day, this makes sense. It is true that these squash do not drop their unfertilized fruit, as other squash will. But neither do they devote a whole lot of resources to those unfertilized fruit. They let them hang around and mature, that’s about the extent of it.
In any case, I haven’t seen a squash vine borer for the best part of a month. I’ve taken the insect-proof covers off. Maybe from here on out the bees will find these squash blossoms, and magic will happen. These squash will produce normal, fertilized, seed-filled squash if the blossoms are fertilized. They just have the additional property of producing these (itty-bitty) mature seedless squash, if they are not fertilized.
So, not a total crash-and-burn, but close. The idea of growing squash in insect-proof enclosures, until the end of squash vine borer season, seems a sound one. So I can use this approach to grow some late-season summer squash, something that would probably not be possible if I tried setting out small plants right now. What I can’t do is keep these parthenocarpic squash completely covered and still expect to get a decent yield of squash.
As I said, if these suddenly spring into galvanic action, and those currently small-but-seemingly-mature squash start to develop, I’ll rewrite this. But as of today, I think I have filled in one tiny little detail that seems to be missing from most write-ups of parthenocarpic summer squash.
