Gadenin日本語Get the appFlower drop in heat is the commonest complaint
A plant covered in flowers that fall off without setting fruit is not diseased and is not short of anything you can buy. Pepper pollen becomes sterile above about 90F (32C) during the day, and it also fails when nights stay above 75F (24C) because the flower cannot cool down overnight. Cold does the same at the other end: below 55F (13C) at night the pollen does not shed properly.
So the flowers open, nothing is fertilized, and within two or three days the whole flower drops at the joint. The plant keeps making more, and as soon as the weather comes back into range it sets normally again. In most hot climates that means an early crop, a midsummer gap, and a second set in autumn.
| Condition | What happens | What helps |
|---|---|---|
| Days above 90F (32C) | Pollen sterile, flowers drop | 30 percent shade cloth, mulch, steady water |
| Nights above 75F (24C) | Flowers drop even in mild days | Shade and airflow; wait for the break |
| Nights below 55F (13C) | Poor pollen shed, drop | Cover at night early in the season |
| Dry soil in flower | Drop plus small misshapen fruit | Water before the plant wilts |
| Heavy nitrogen feed | Lush leaves, flowers drop | Switch to potassium weighted feed |
Tapping the stakes gently in the middle of the morning helps peppers set when humidity is high, because they are self fertile and only need the pollen shaken loose. It does nothing at all when the cause is heat, because there is no viable pollen to shake.
Fruit disorders that are not disease
Three of the four things most likely to spoil your fruit are physiological. Recognizing them saves you spraying for something that is not there.
| What you see | Cause | What to do |
|---|---|---|
| Sunken leathery brown patch at the blossom end | Blossom end rot: uneven water | Mulch, water steadily, cut nitrogen |
| Papery white patch on the sun facing side | Sunscald | Keep leaf cover, shade in peak heat |
| Corky tan lines on the shoulders | Growth cracking after rain on dry soil | Even watering; the fruit is still edible |
| Small, flat, lopsided fruit | Poor pollination during heat or cold | Nothing to fix; pick them and wait for the next set |
| Soft watery rot at the stalk end | Fungal rot entering damage | Remove the fruit, improve airflow, do not compost it |
The pests worth watching for
Peppers get off comparatively lightly, and most of what arrives can be dealt with by hand if you look twice a week. Turn a few leaves over in the cool of the morning and check the growing tips, because that is where everything starts.
| Pest | How you notice | What to do |
|---|---|---|
| Aphids | Sticky leaves, curled growing tips, ants | Wash off with water; they carry virus, so do not let them build |
| Whitefly | Clouds of small white insects when disturbed | Yellow sticky traps and keeping the plant unstressed |
| Thrips | Silvery streaking, distorted new leaves | Reflective mulch; check inside the flowers |
| Spider mites | Fine speckling, webbing under leaves in heat | Spray leaf undersides with water; they thrive on dry, dusty plants |
| Pepper weevil or fruit borer | Small hole in the fruit, early fruit drop | Pick up and remove all dropped fruit; never leave them lying |
| Cutworms | Young plant severed at soil level overnight | A card collar around the stem at planting |
Aphids matter far more for the viruses they carry than for the sap they take. A plant with mottled, puckered, narrow new leaves that never comes right is usually virused, and the only answer is to pull it out.
Diseases and when to give up on a plant
Leaf spots and wilts are less common on peppers than on tomatoes, but when a wilt does arrive it comes from the soil and no spray reaches it. Knowing which ones are treatable and which are not saves you weeks of pointless effort.
| Symptom | Suspect | The call |
|---|---|---|
| Sudden wilt, stem dark at soil level | Phytophthora root and crown rot | Pull the plant; improve drainage and do not replant nightshades there |
| Yellowing that starts on one side | Verticillium wilt | Pull it before it spreads; rotate next year |
| Small dark leaf spots with pale centers | Bacterial leaf spot | Remove the worst leaves, avoid overhead watering, do not save seed |
| Sunken circular lesions on ripening fruit | Anthracnose | Pick affected fruit off the plant and remove them from the plot |
| Mottled, narrow, puckered new leaves | Virus, spread by aphids or thrips | Pull the plant; there is no treatment |
Do not stack pulled plants at the edge of the plot or dig them in. Burn them or put them in household waste, and wash your hands and snips before touching healthy plants.
Prevention is mostly decided before you plant
Rotate at least three years away from peppers, tomatoes, aubergines and potatoes. Space plants 18 to 24 inches (45 to 60 cm) apart so air moves through them. Mulch. Water at the base rather than over the leaves, and do it in the morning so anything splashed dries before nightfall.
Those five things remove most of the conditions the problems need, and every one of them is a decision made at or before planting rather than a reaction afterwards.
Keeping a record makes the pattern obvious
Write down the week flower drop started and the week it stopped, the position of any plant you pulled and what it looked like, and the date you first saw aphids. Two seasons of this and you will know your own garden's midsummer gap to within a week, which lets you put shade cloth up before the flowers fall rather than after.