Pepper Blossom-End Rot: Causes and How to Fix It
That sunken, leathery brown patch on the bottom of your peppers looks alarming, but blossom-end rot isn't a disease or a pest — it's a calcium-delivery problem driven almost entirely by uneven watering. Here are the real causes, how to tell them apart, and how to stop it spreading to the next round of fruit.
Inconsistent watering (the usual culprit)
What's happening
Calcium can only reach the developing fruit when water moves steadily through the plant. When the soil swings from bone-dry to soaked, the fruit's far end is starved of calcium at the critical moment and the tissue collapses into a sunken brown patch.
How to confirm
The spot is on the blossom (bottom) end, not the stem end, and is dry and leathery rather than soft and mushy. It usually shows up after a heat wave, a missed watering, or a heavy rain following a dry spell. Often only the first flush of fruit is affected.
How to fix it
Even out the watering immediately — aim for deep, consistent moisture, roughly 1–2 inches a week, applied 2–3 times rather than in erratic bursts. Pick off the affected peppers so the plant redirects energy to new fruit. Later fruit on a now-evenly-watered plant should come in clean.
Prevent it
Mulch with 2–3 inches of straw or shredded leaves to buffer soil moisture, and water on a steady schedule rather than waiting for the plant to wilt.
Low or unavailable soil calcium
What's happening
Sometimes the soil genuinely lacks calcium, or the pH is off enough that the calcium present can't be taken up by the roots even when watering is perfect.
How to confirm
The problem persists even after you've steadied your watering, and it shows on most fruit rather than just the first flush. A soil test confirms low calcium or a pH outside the ideal 6.2–6.8 range.
How to fix it
Test the soil and correct the pH toward 6.2–6.8 so existing calcium becomes available. Where a test shows a true deficiency, work in a calcium source such as garden lime or gypsum before or at planting; mid-season, even watering does more than any quick spray.
Prevent it
Amend beds with compost and test pH before each season, adjusting with lime well ahead of planting so calcium is in place from the start.
Too much nitrogen or damaged roots
What's happening
Heavy nitrogen feeding pushes fast leafy growth that pulls calcium toward foliage and away from fruit, while disturbed or cramped roots simply can't move enough water and calcium to keep up.
How to confirm
You've been feeding a high-nitrogen fertilizer and the plant is lush and dark green with rot on the fruit, or the problem followed close cultivation, transplant shock, or a tightly root-bound container.
How to fix it
Switch to a balanced or slightly phosphorus-and-potassium-forward fertilizer and ease off nitrogen. Avoid hoeing or digging close to the roots, and give container plants a large enough pot that roots aren't choked.
Prevent it
Feed moderately rather than heavily, mulch instead of cultivating near the base, and use roomy containers with quality mix.
When to worry (and when not to)
Blossom-end rot on the first flush of fruit is extremely common and rarely a sign of real trouble — steady your watering, remove the affected peppers, and later fruit almost always comes in clean. Worry only if it continues across every flush despite consistent moisture, which points to a genuine soil calcium or pH problem worth a soil test. The rot itself doesn't spread plant to plant, so there's no need to pull or treat the whole plant.