Why Is Your Zucchini Plant Stem Splitting? [5 Top Reasons]

Zucchini plant stems can split from too much weight, high-speed winds, rough handling, insect infestations, and inconsistent watering. The long, hollow stems work overtime to support the big leaves and heavy fruit. So, any additional stress can easily cause the stems to split apart. You can potentially repair the broken stem to keep your plant alive. In some cases, the zucchini might even repair itself if left alone. Breakage will keep happening, however, unless you fix the cause.

Zucchini plant stem splitting

5 Reasons Why Your Zucchini Plant Stem is Splitting

Zucchini plant stems split easily when put under too much stress. Resolving the underlying cause of the breakage is key in keeping the plant alive all season.

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Too Much Weight

Large leaves and fruit can cause the stems of zucchini to split apart. The risk of breakage increases when growing plants vertically. You must check the plants daily to pick the zucchini squash before they get too big. Aim to pick the fruit when it’s five to seven inches long for the best taste and texture.

High-Speed Winds

Zucchini stems cannot stand up to the forces exerted by high-speed winds. Just one windy day is all it takes to ruin your chance at a big squash harvest. Avoid that by protecting your plants with windbreaks. Planting tall grasses, shrubs, and trees work best to block the winds, but this isn’t always ideal for home gardens. A trellis or tomato cage, like this one, can help block strong winds and grow healthy plants.

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Rough Handling

Rough handling can quickly result in broken stems on your zucchini plants. So, give your plants a tender touch to avoid damaging their hollow structures. Never twist or yank on your plants while trying to prune or harvest them. Gently push the leaves out of the way as you work. Use these sharp pruning shears to cut clean through the stems without any tugging.

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Insect Infestation

Insects like the squash vine borer can leave your zucchini stems split in an instant. Vine borers create entrance holes in the stems and then lay their eggs inside. Soon after, the larva eats the plant matter in the stems to grow into their adult form. Other insects that cause stem splitting include squash bugs and striped cucumber beetles. These row covers can be used to prevent insect infestations. Just be sure to remove them for pollinators.

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Inconsistent Watering

Inconsistent watering can cause zucchini stems to split wide open. Zucchini prefer to get about one inch of water per week total. For best results, give each plant about a ½ gallon of water per day. Letting the plants dry out too much, and then overwatering zucchini plants will split the stems. Heavy rainfall can have a similar effect. Shield your plants from excessive rain by putting plastic sheeting over them for the day.

How to Fix a Broken Zucchini Stem 

There are several ways to fix a zucchini’s split stem. For a stem split near the soil, mound up the dirt to cover the root node above the split. Split stems well above the soil line need grafting. To do so, cut away the broken portion of the stem. Then, reattach the pieces together using this grafting tape.

  • Grafting tape can be used to repair a broken zucchini stem.
  • A split stem on a zucchini plant can sometimes continue to grow without needing repair.
  • Trim the stem back to the crown if the first frost hasn’t hit yet.

For a hands-off approach, just leave the stem alone in hopes of it continuing to grow without a problem. If all else fails, consider trimming the main stem back to the crown. You should still get a good harvest if there’s still enough time before the first frost.

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Will a Broken Zucchini Stem Fix Itself?

A zucchini stem split can fix itself if a complete break hasn’t occurred. The broken plants will attempt to regenerate tissue to repair the split stem. The repair process can take a lot of the plant’s energy. You may notice a decrease in its overall growth as a result. Sometimes, the zucchini will stop producing squash.

  • Broken zucchini stems do have the potential to repair themselves, as long as they don’t experience full-blown stem splits.
  • The repair process can take a lot of energy from the plant, resulting in poor fruit growth.
  • You can replace your zucchini squash plant if it’s still early in the season.

Attempting to repair or remove the broken stem can speed up the healing process. If it’s early enough in the season, you might want to replace the plant altogether. Look at the severity of the stem damage and its location to decide what to do.

Why is the Stem of Your Zucchini Plant Splitting?

Zucchini stem splits and cracks in stem bases are usually a result of the following:

  • Too much weight
  • High-speed winds
  • Rough handling
  • Insect infestations
  • Inconsistent watering

When the stems on your plants break, it’s often possible to repair them. If not, you can either let the plant attempt to repair itself or cut it back. It’s also a good idea to plant a few extra zucchini plants each year to proactively be ready for any issues, and ensure the best harvest by the end of the season.

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