By knowing about pepper plants flowering, pollination, and fruit setting phases a gardener is better equipped to make sure the plant successfully produces a good yield come harvest time.
Should I Pinch Off Pepper Flowers
There are two times it makes sense to pinch flowers off of pepper plants: if the pepper plant is flowering too early or at the onset of flower production to encourage more flowers to grow.
If a pepper plant starts growing flowers during the first 10 weeks after it sprouts flowers should be picked off the plant.
At this stage we want the pepper plant in a vegetative growth stage so that it grows into a big bushy plant that can support more peppers come flowering and pepper production time.
Pinching off flowers when the plant first starts to flowers for about 10 days may increase yields at harvest time.
The thought is that by picking off flowers right when they start to appear the plant will produce more flowers than it would have if left alone and more flowers equals more peppers.
Problems With Pepper Plants & Pollination
Flowers Falling Off of Pepper Plants
As stressful as it can be to see pepper plants dropping their flowers, it’s important to keep in mind that some flower drop is natural! Some cultivars may be less likely to drop flowers than others.
Common culprits of excessive flower drop include temperatures too high or low, irregular watering, soil nutrient levels too high or low, excessive wind, or anything else that can stress the plants like pests and disease.
Temperature Range – Although peppers flourish in full sun, extreme heat is one of the most common reasons that flowers fall off pepper plants. Heat waves induce stress on the pepper plant. Blossom drop can also be expected if temperatures are too cool.
Temperatures greater than 90 degress or less than 55 degrees result in heavy blossom drop.University of Wisconsin, Cooperative Extension, Page 7
Shade cloths are a solution to heat stress and sun scald on peppers. Putting mulch on the soil can help keep soil cool and help it to retain moisture.
Under Fertilized – Blooming plants require phosphorus to minimize risk of flower drop and encourage pepper plants to produce healthy buds and fruits. If pepper plants aren’t receiving enough phosphorus, even flowering plants may struggle to produce pods.
To learn more about that check out “Best Soil & Fertilizers for Pepper Plants“.
No Flowers on Pepper Plants
Even healthy-looking pepper plants cannot produce any peppers without flowers. If you have no flowers on your pepper plants it may be too early in the season or weather conditions or soil nutrient levels may be to blame.
Adequate Sun – Ensure that pepper plants are getting at least 6 hours of sun. If the plant is not getting enough sun, it will not have enough energy to produce blossoms, let alone fruit.
Temperatures Too Cold – Early in the season, cold weather conditions can reduce the chance of flowering. Ensure the soil is warm enough before transplanting and that all chances of frost have passed. Temperatures below 60℉ at night may slow growth and ultimately make it difficult for the pepper plant to form buds.
Over Fertilized – Most gardeners wouldn’t suspect anything is wrong with a green, healthy-looking pepper plant until it doesn’t produce buds. Pepper plants in soil with too much nitrogen may delay flowering or not flower at all. High levels of nitrogen prompt the plant to continue producing leaves and stems instead of flowers and buds.
You might be interested in “Do Bloom Booster Fertilizers Work?“
Under Fertilized – On the other side of the spectrum is under fertilization. If the soil doesn’t have enough of a critical nutrient it may not grow flowers or peppers. Use a soil test to determine soil nutrient levels and pH levels.
The soil test linked above is similar to soil tests most University Extensions offer. It will measure 13 nutrient levels as well as the pH level of the soil.
If pH levels are too high or low plants are unable to absorb nutrients even when they are present in the soil.
Pepper Flowers Not Being Pollinated
Environmental stressors similar to those mentioned above can cause poor pollination rates. Natural pollination is impossible if there is a lack of bees, butterflies and other insect pollinators. If peppers are in an isolated location outdoors or there are no other pollinator-plants or flowers nearby, it can make it challenging for pollinators to locate the pepper blossoms.
Wind – Too much wind can tear flowers off the plant or lessen bee activity. Not enough wind may prevent the pollen from being distributed at all.
Humidity – The ideal humidity conditions vary with type of pepper, but consistently high relative humidity’s can decrease the viability of the pepper flower’s pollen grains and cause the pollen to remain stuck to the male part of the plant. If humidity is too low, pollen may not be able to stick to the female part of the flower.
Soil Nutrient Levels – Nutrient-levels of the pepper plants themselves may also decrease likelihood of pollination. If plants are deficient in nutrients, overfertilized to the point of toxicity, or have a general nutrient imbalance, they will be less desirable to pollinators.
Check out “Pepper Plant Growing Tips” for more ways to make sure pepper plants have what they need to thrive.
Pepper Plants Pollination & Fruit Setting
How To Hand Pollinate Pepper Plants
Whether it’s due to environmental conditions or lack of pollinators, not all hope is lost if pepper plants are not being successfully pollinated. To increase the chance of fruiting, gardeners can try their “hand” at hand-pollination.
For successful pollination to occur, pollen must be transferred from the male part of the flower to the female part of the flower.
Bees, butterflies, and other insects are pollinators because they help with this transfer of pollen. To hand-pollinate, gardeners must simply replicate this transfer manually.
For the best chance of successfully recreating natural pollination, wait until the afternoon (between noon and 3pm) when the pollen is at its peak and when humidity levels are moderate.
The easiest way to hand-pollinate is to gently shake the pepper plants while they are blooming. This can encourage the release of pollen, and is especially helpful if there’s not any wind. Gently shake the flowering peppers each day to maximize chances of pollination.
For a more “hands-on” approach, a small paintbrush or cotton swab can be used to transfer the pollen from blossom to blossom. Since pollen is naturally sticky, it should adhere to these surfaces without a problem. If pollen isn’t sticking, the paintbrush or cotton swab can be dipped in a small amount of distilled water to help it adhere.
An electric toothbrush or the Bee Pollinator can also be used to hand-pollinate pepper plants. Some gardeners prefer this method, as the vibration of the toothbrush closely mimics the vibration of a bee’s wings. Since pepper plants are accustomed to pollination by bees, they may be more likely to release pollen when a similar vibration is used.
To hand-pollinate with an electric toothbrush, turn the toothbrush on and touch the bristles to each flower on the pepper plant. Remember to be slow and extremely gentle when hand-pollinating to prevent any damage to the blossom. If hand-pollinating multiple types of pepper plants, clean or switch to a new pollination tool to prevent cross-pollination.
Pepper Plants & Cross Pollination
Although peppers are self-pollinating they do cross-pollinate with flowers of the same and different varieties. Cross-pollination occurs when pollen from one plant is transferred to another plant. Something like 12% of pepper flowers are pollinated by cross-pollination.
The effects of cross-pollination between different pepper varieties will not be seen unless cross-pollinated seeds are saved and planted the following year.
If desired, there are ways to limit the chance of cross-pollination, but these methods are only necessary if saving seeds. They involve separating different varieties of pepper by long distances with physical barriers between them or putting bags over flowers until they self-pollinate.
Here’s a good resource on saving pepper seeds by UC Davis.
Each pepper flower has both male and female reproductive organs. Flowers with this trait are called “perfect flowers”, and are able to self-pollinate.
Although pepper blossoms do truly self-pollinate by transfer of pollen within the same flower they still benefit from contact with pollinators.
While searching for pollen in the flower, pollinators can help shake the pollen loose from the male part of the flower, helping it transfer to the female part of the flower.
During cross-pollination of two different varieties the genetic material of each plant combines to create a new variety.
Cross-pollination is sometimes done intentionally to create new varieties or to bring out certain desirable characteristics, but does not affect the characteristics of the fruit on an already growing plant.
Pepper Plant Flower Fruit Drop
Gardeners of all experience levels can become stressed when flowers or fruits start dropping off pepper plants. It turns out that the pepper plants might be just as stressed as we are!
Pepper Plant Flower Fruit Drop Caused By Blossom End Rot
Blossom-end rot is a disease caused by calcium deficiency that can cause pepper fruit to drop off the plant. It can occur at any growth stage of the fruit and appears as a black and leathery lesion.
Blossom-end rot is a non-parasitic physiological disease that typically occurs during extended dry periods. It is triggered when the pepper fruit does not have enough calcium. The problem gets tricky because even if there is enough calcium in the soil the plant may not be uptaking enough calcium.
Pepper fruit receives calcium along with other nutrients from the plant at night. Water stress of any kind interferes with this calcium uptake, causing the fruit to receive very little calcium.
The presence of low amounts of calcium and excessive amounts of ammonium, potassium, nitrogen or magnesium in the soil can also interfere with calcium uptake into the pepper fruit.
Eventually, lesions will enlarge and turn leather and dark brown or black. The open wounds on the pepper fruit may attract bacteria and fungi. If blossom rot lesions turn soft, watery, have a fuzz-like growth on them, or are cracked, it is likely that the lesion was invaded by microorganisms.
To spot blossom-end rot, look for a light-tan water-soaked lesion on the blossom end (opposite of the stem) of the fruit. If blossom-end rot is spotted, it is recommended to remove the affected fruit as soon as possible to promote healthy development of any other pepper fruits on the plant.
Pepper Plant Flower Fruit Drop Caused By Stress
If exposed to too much environmental stress, blossoms and even pepper fruits themselves can drop from the plant.
The same stressors that cause pepper flowers to drop can cause the fruit to drop. Exposure to extreme temperatures — whether cold or hot — will cause a pepper plant stress. Colder temperatures pose a problem in early spring or in late fall. Fruit may start to drop if nighttime temperatures are consistently below 55℉.
Consistently hot temperatures in the summer can also cause plants to drop peppers. Risk increases if temperatures during the day are consistently above 90℉ or temperatures at night are above 75℉.
When temperatures are outside of the ideal range for peppers, plants are unable to properly absorb the nutrients or regulate water levels necessary to produce a pepper.
The more stressed a pepper plant becomes the more likely it is to drop fruit. Other growth conditions, such as too much or too little water, incorrect levels of nutrients in the soil, a bad soil pH, and lack of sunlight can contribute to a pepper plant’s stress.
Please comment below with your own thoughts and experiences with pepper plants flowering, pollination, and fruit setting!