To harvest, or not to harvest?
There is an art to harvesting mini squash. You have to learn to anticipate how fast the fruit are growing to know when to harvest, and when to leave the fruit to get a little bigger.
There’s always more incipient fruit waiting in the wings. The younger buds and their ovaries (mini squash) grow very slowly while the plant puts most of its resources into growth of the oldest, largest fruit on the vine. Once that largest fruit is picked, or once it has put on most of its growth and starts to mature seeds, the next largest fruit will grow that much faster.
Plant physiologist refer to the fruit as a “sink” for resources such as nutrients transported from the roots, and sugars created by photosynthesis in the leaves. The larger the fruit, the more resources are diverted to that sink. The larger and healthier the plant, the more resources there are to invest in the fruit sinks. When fruits are allowed to grow until the seeds are mature, as in winter squash or melons, then less of the resources go into making stems and leaves. If the fruits are harvested small, and are not allowed to mature, the plant has excess resources for making more flowers and more mini squash, but also more stems and leaves that can, in turn, make even more flowers and mini squash.
I always have this in the back of my mind when I harvest. I have a target size for harvesting the fruit. For zucchini types, mini squash are best at about 4 inches long. Patty pan types are best about 1.5 to 2 inches in diameter. If a fruit is marginal in size when I’m harvesting, I have to decide whether or not to harvest. It’s a game of skill and chance.
I’m looking at the largest fruit, the one that bloomed yesterday or the day before, but also the second largest to see how close it is to harvestable size. Sometimes there are two fruits close together that are almost identical in size. I have to take into account that the plant is probably putting equal resources in each of those fruits, so the two are growing a little slower than one dominant fruit would grow.
If it’s the last squash harvest of the day on Friday, I'll harvest a marginal sized fruit no matter what, because I can bring it to market the next day. Plus, I may not get back to harvest until Sunday morning. On warm days, the squash could be too big by then. Instead, I let the next largest squash become the sink so it will be ready to harvest next time.
If there is time on Fridays I harvest twice; once first thing in the morning, and once at the end of the day. In the morning I’ll leave marginal squash on the vine, in hopes that they will be the perfect size by the end of the day. But if the second largest squash looks like it might be harvestable by the end of the day, I’ll take the largest squash in hopes of harvesting two squash from one plant that day.
Similarly, if it’s a week day, I am inclined to leave a marginal squash on the vine for another day in hopes that it will be perfect the next day. If it’s a warm day, or if I am late harvesting, it may get a little too large. If it’s a cold day, the marginal squash could take several days to reach harvestable size. Then I tend to harvest mini squash at a smaller size.
Sometimes the fruit grows past mini squash size, and I decide to leave it until it’s a “midi” or “maxi” fruit size. Then I aim for a fruit about 7 inches long for zucchini types. That may take several days of growth.
I may notice squash slow pokes. A squash that should be the dominant sink on a plant may not grow as fast as expected. I’ll suspect a stronger sink hidden somewhere at the base of the plant. I often find one – the huge squash that suddenly becomes visible when it reaches baseball bat size.
I have to know my squash plants intimately to play this source-sink harvest game. I remember each fruit configuration from day to day, noting how much has changed since the previous day, watching the sky, the soil, the weather forecast to predict how fast change will occur in the future. Change is constant in my squash patch, and often dramatic, until it is abruptly halted by a heavy frost.
My squash patch is a metaphor for my life. I watch the young seedlings burst forth into the world and grow day by day with the exuberance and uncertainty of children. It takes maturity and experience to recognize and appreciate the rate at which they grow, and to prepare for change. Just when I think I am good at it, the weather changes, the temperature drops. Growth and change occur at a different pace. I have to learn and adapt all over, hoping to continue to be productive until the final frost.