Growing Peppers: Common Problems & Solutions
Nitrogen Deficiency
Manifestation: Yellowing leaves that curl inward. Plant growth stunted. Plants become more susceptible to insect damage.
Cause: Nitrogen deficiency.
Solution: Fertilize with a high-nitrogen fertilizer. I use liquid Alaska Fish Fertilizer (5-1-1) for all my seedlings.
See our Pepper Growing Guide for more info.
Caveats:
This is the most common issue that isn’t pest related. You want leaves to be lush and green.
Above: The pepper on the left suffers from a Nitrogen Deficiency, with yellowish leaves curled inward (“taco-ing”) and obvious stunting when compared to the healthy plant on the right
Above: Peppers with severe nitrogen deficiency.
Edema
Manifestation: Raised white, yellow, or orange dots on leaves resembling salt. Rough texture. Wilting on affected leaves.
Cause: Poor Airflow
Solution: Run fan 24/7 on all pepper plants when in any structure.
Caveats: Continue normal watering. Do not pull back on watering, as this can cause further issues.
Pictures:
Edema on Jalapeño pepper’s mature leaves; new growth shows improvement.
Mature leaf with edema, causing wilting.
Mature leaf underside.
Aphids
Manifestation: Little green or gray bugs on your plant, usually concentrated on the newest leaves. Ants are also a sign aphids are on your plant, as they feed off the aphids’ dew. Aphids will eventually destroy your plant through sap sucking.
Cause: Aphids are sap suckers. They damage plant tissue directly.
Solution: Check for aphids daily. 50% alcohol spray + soapy water daily at first sign of aphids. Prune bottom leaves / leaves that touch soil and each other to reduce aphid mobility. Affected leaves will remain ugly. Prune and trash/burn affected leaves or leave on - new growth will take over. If entire plant is affected by browning/bronzing, burn or trash it.
Caveats:
This treatment also works on mealybugs, wooly aphids, and other soft bodied insects.
Don’t use more than 50% alcohol or your leaves will burn.
While concentrated on new leaves, check the underside of all leaves.
Pictures:
Fungus Gnats
Manifestation: Curled leaves, sickly looking plant, non-raised browning or bronzing on leaf undersides. If left untreated, leaves will brown and drop.
Cause: Fungus gnat larvae feeding on the roots of your pepper plant.
Solution:
Do not overwater. Let top of soil dry out before re-watering.
Use yellow sticky traps from the start of germination.
Turn fans on 24/7.
Use Mosquito Bits to water any trays/pots heavily infected with fungus gnats to kill larvae. Mosquito Bits are a pelleted form of Mosquito Dunks.
Don’t let food or rotting plant material anywhere near seedlings.
Check and clean your household drains if they harbor fungus gnats.
Caveats:
Fungus gnats require all possible defenses, not just one. Mosquito Bits are not critical if you are on top of fans and sticky traps. Mosquito Bits is not cheap, and it’s not feasible to water with it for more than a week.
Without close examination of flying gnats around the soil, you may underestimate your gnat infestation until it’s too late.
If there are still fungus gnats in the vicinity and you don’t know why they aren’t decreasing, make sure to check for anything rotting in the room. In the past, I had harvested Ground Cherries and forgotten them in a bin. When I found opened the bin, a cloud of fungus gnats flew into my face. Just today, I found this season’s onion starts I had forgotten in a plastic bag. It was a gooey mess full of fungus gnats! Check around! ;)
Pictures:
Habanero pepper with severe leaf curling and drooping. Leaves droop sharply from the middle. New growth dies.
Bronzing on the underside of leaves crossing leaf veins and showing splotching patterns.
More bronzing on the underside of leaves. Bronzing will affect tops of leaves at later stages.
Habanero with extensive fungus gnat damage, with severe leaf drop. These plants are in recovery after Mosquito Bits, traps, and fans. Notice the new growth emerging. These plants will survive, although will be far behind other trays their same age. Some damage around leaf margins is sunscald, as trays were not treated nicely after infestation was discovered.
Habanero with damage from the side. Leaf drop. Bronzing on leaf underside. Top new growth necrosed.
Habanero with damage from above. Notice the fungus gnat on the top right leaf :p
Healthy habanero with natural leaf mottling/curling.
Damping Off
Manifestation: Seedlings fall over and die. In older seedlings, it causes stem girdling and peppers fall over and languish.
Cause: Fungi on the soil surface from poor airflow.
Solution: Increase airflow. Always run a fan on your seedlings. This will also help resist fungus gnats and strengthen your stems.
Pictures: See a Diagram on Edinburgh Garden School
Sunburn / Sunscald
Manifestation:
Leaf: affected portion of leaf dries and turns brown/tan.
Pepper fruit: affected portion of fruit becomes squishy and turns tan/brown. Pepper rots.
Cause:
Leaf: plant was not hardened off appropriately. Got too much sun after being inside or in the shade.
Fruit: leaves on the plant are not sufficiently covering peppers from the summer sun.
Solution:
Leaf: harden off your peppers.
Fruit: Plant peppers close together (12” / 30cm apart). This increases shade and helps keep peppers upright. Keep pepper upright with stakes, tomato cages, or Florida Weave (great for rows of many peppers).
Harvest any with damage and use or process immediately.
Pictures
Leaf sunscald (top left)
Pepper sunscald (Google Image Search)
