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Blossom end rot on squash is a common garden problem that can be frustrating.
Fortunately, you can do something about blossom end rot on squash by addressing the underlying cause, which is almost always a calcium deficiency.
If you’ve been noticing those dark, sunken spots on the bottom of your squash, you’re not alone.
It’s one of the most frequent issues gardeners face when growing squash, tomatoes, and peppers.
In this post, we’ll explore what causes blossom end rot on squash, how to treat it, and most importantly, how to prevent it from happening again.
Let’s get to it.
What Causes Blossom End Rot On Squash
Blossom end rot on squash happens when the fruit doesn’t get enough calcium during development.
But here’s the thing, it’s rarely about your soil lacking calcium.
Most of the time, it’s about the plant not being able to take up the calcium that’s already there.
1. Inconsistent Watering
Calcium moves through your squash plant with water.
When your watering is inconsistent, going from bone dry to soaking wet, the plant can’t absorb calcium properly.
This is probably the number one cause of blossom end rot on squash.
Squash plants need steady moisture, not a feast-or-famine situation.
2. Calcium Deficiency In The Soil
Sometimes the soil genuinely lacks calcium, especially in sandy or acidic soils.
A soil test will tell you for sure, but if your pH is below 6.0, calcium might not be available to your squash plants.
The ideal soil pH for squash is between 6.0 and 6.8.
3. Root Damage
If your squash roots are damaged, they can’t take up water or nutrients.
Overwatering, root rot, or even hoeing too close to the plant can cause this.
Damaged roots mean no calcium delivery, and blossom end rot on squash is the result.
4. High Nitrogen Fertilizer
Too much nitrogen encourages lots of leafy green growth but can interfere with calcium uptake.
Your squash plant ends up putting energy into leaves instead of fruit development.
How To Treat Blossom End Rot On Squash
When you spot blossom end rot on squash, don’t panic.
Here’s what you can do immediately:
1. Remove Affected Fruit
Pick off any squash showing signs of blossom end rot.
Those fruits won’t recover, and leaving them on the plant just wastes energy.
Plus, removing them prevents the problem from spreading to other developing squash.
2. Water Consistently
Set up a regular watering schedule for your squash plants.
Deep water once or twice a week rather than light sprinkling every day.
Mulch around your squash to retain moisture and keep the soil evenly damp.
3. Add Calcium If Needed
If a soil test confirms low calcium, amend with gypsum or lime.
For a quick fix, some gardeners spray a calcium chloride solution on the leaves.
Just know that foliar sprays help, but they’re not a cure-all for blossom end rot on squash.
4. Avoid Over-Fertilizing
Skip the high-nitrogen fertilizers during fruiting.
Use a balanced fertilizer or one that’s lower in nitrogen and higher in phosphorus and potassium.
How To Prevent Blossom End Rot On Squash
Prevention is way easier than trying to fix blossom end rot on squash after it shows up.
Here’s how to keep it from happening:
1. Maintain Consistent Soil Moisture
Don’t let your squash soil dry out completely.
Aim for evenly moist soil, not soggy.
Drip irrigation or a soaker hose works wonders for keeping moisture consistent.
2. Test Your Soil Before Planting
A soil test takes the guesswork out of gardening.
It tells you your pH and calcium levels before you even plant your squash.
Adjust as needed so your squash has everything it needs from the start.
3. Don’t Overwater Or Underwater
Both extremes cause problems.
Squash plants typically need about an inch of water per week.
Adjust based on rainfall and temperature so blossom end rot on squash doesn’t stand a chance.
4. Use Mulch
Mulching around your squash plants helps regulate soil temperature and moisture.
It also prevents soil from splashing onto the fruit, which can contribute to other issues.
Straw, shredded leaves, or grass clippings all work great.
So, What To Do About Blossom End Rot On Squash?
What to do about blossom end rot on squash comes down to fixing the calcium uptake issue.
Remember, it’s not always about adding more calcium to the soil, it’s usually about watering consistently.
Remove affected fruit, water deeply and regularly, and test your soil before planting next season.
With a little attention to moisture and soil health, you can say goodbye to blossom end rot on squash for good.
Your squash plants will thank you with a healthy, bountiful harvest.