Rot in the first zucchini. Sometimes it’s common, sometimes it isn’t

Are your zucchini growing yet? Ours are, and especially the classic green ones—we already have some that are ready to harvest. It’s a different story with the yellow ones. Still, it’s worth addressing one of the traditional issues that accompanies zucchini ripening: zucchini rot. This is very unpleasant. It doesn’t always occur. In the following paragraphs, we’ll take a closer look at this problem. Sometimes action is needed; other times, it isn’t necessary.

A healthy plant bears fruit, but the fruit is rotten

If we look at the zucchini plant itself, we’ll notice that many fruits are slightly brownish or yellowish—and often turn black—at the spot where the flower falls off. Gradually, this brownish and yellowing color spreads throughout the entire fruit, which is, of course, unusable. Not all zucchini are affected this way, but many do rot.

Photo: Radek Stepan

Sometimes less is more

We leave the plants as they are, simply removing the affected fruits. The plants are usually able to produce enough fruit that we can afford to do this. Those few rotten zucchini simply end up in the compost.

Tip: We made sweet zucchini dessert. It’s delicious.

Why do zucchini rot?

Traditionally, this is because the plant cannot absorb large amounts of calcium from the soil. It can absorb it, but only up to a certain limit. That’s enough to produce a certain number of high-quality zucchini.

If we want to address the situation…

Simply choose a specific fertilizer that contains enough calcium. Crushed eggshells can also help. However, as we mentioned above, we don’t fertilize our zucchini because we don’t consider it necessary.

This doesn’t happen with yellow zucchini

Another interesting observation we’ve made after several years of growing zucchini is that you can avoid zucchini rot by sowing or planting yellow zucchini. From this perspective, they are much more resistant, and they also taste excellent, as they are slightly firmer than the classic green ones.

Photo: Radek Stepan

Sources: Author—grower

Photo: Radek Stepan