Common Misconceptions in Greenhouse Pepper Cultivation and Their Solutions

Greenhouse peppers can generate substantial income for farmers, which is why they are widely cultivated. Today, we’ll share some key tips on greenhouse pepper cultivation and management, as well as the important considerations to keep in mind when growing them.

Misconception 1 in greenhouse pepper cultivation:

The more fertilizer you apply, the more the plants grow. In fact, for peppers to grow normally, the soil’s total salt concentration should be between 2,000 and 3,000 mg/kg; if it exceeds 6,500 mg/kg, the roots will experience reverse osmosis and wither, inevitably reducing yield. Inside greenhouses, high temperatures and high humidity accelerate the decomposition of organic fertilizers, boosting phosphorus use efficiency by 2–3 times compared to open fields, while nitrogen volatilization is substantial. Over-fertilization can easily lead to fertilizer damage.

Solution:

① For greenhouses that have been cultivated for more than three years, the application rate of cattle manure should be limited to no more than 2,500 kg per mu, and chemical fertilizer use should be reduced by approximately 50%.
② In plots with high total salt concentrations, apply additional organic fertilizer, humic acid fertilizer, and EM microbial fertilizer to increase the soil’s carbon-to-nitrogen ratio, improve soil aeration by loosening the soil, and mitigate salt accumulation and fertilizer-induced damage.
③ Supplement micronutrients such as boron, zinc, and magnesium to balance soil nutrition, thereby creating favorable conditions for reducing input costs and achieving consistently high yields year after year.

Misconception #2 in greenhouse pepper cultivation:

A high seedling density leads to lower yields. Many vegetable growers, when setting out seedlings, opt for a denser planting, believing that more plants will result in higher production. In fact, during the winter, low temperatures and weak light reduce photosynthesis, limiting carbohydrate synthesis; only proper thinning can ensure high yields. Measurements show that with four pepper plants per square meter, the plants’ own growth consumes about 50% of the photosynthates, while the fruits account for the remaining 50%. By contrast, planting eight plants per square meter shifts the balance: the plants consume 70%–80% of the photosynthates, leaving only 20%–30% for fruit production. Overcrowding not only lowers yields but also causes plants to grow excessively tall in their struggle for sunlight, and poor air circulation makes them more susceptible to various fungal and bacterial diseases.

Solution:

① For overwintering pepper crops, it is best to plant at a reasonable, sparse density.
② To make full use of space, adopt a management strategy of dense planting in the early stage, thinning plants in the mid‑stage, and pruning branches in the later stage, ensuring that foliage and branches remain well spaced, thereby increasing total yield and overall economic returns.

Misconception #3 in greenhouse pepper cultivation:

High temperatures promote rapid growth. Many vegetable growers believe that greenhouses are built to retain heat, and that higher temperatures accelerate pepper development. In fact, peppers have an upper temperature limit—typically 25–32°C—and excessively high temperatures can inhibit young fruit set, leading to gaps in the fruiting sequence. Moreover, when temperatures are too high, respiration rates increase, disrupting normal physiological processes, causing excessive vegetative growth, and creating an imbalance between vegetative and reproductive development, which ultimately reduces yield.

Solution:
① Install two ventilation openings in the greenhouse to promptly reduce temperatures.
② Manage the crop strictly according to the temperature requirements of each growth stage and the optimal temperature ranges for the development of its various organs, taking care to avoid high temperatures that can result in vigorous vegetative growth without fruit set.

Misconception Four in Greenhouse Pepper Cultivation:

The plants exhibit vigorous growth. Many vegetable growers believe that robust plant vigor is a sign of healthy crops; however, excessive water and lush foliage typically result in shallow root systems, and overly vigorous vegetative growth inevitably impairs reproductive development, leading to lower yields.

Solution:
① During the seedling stage, water and plant growth are restricted to promote root development, ensuring that approximately 60% of photosynthates are allocated to the underground parts, while in the mid-to-late stages, the underground and aboveground portions each account for 50% of total uptake.
② In the early stage, vegetative growth accounts for 60% and reproductive growth for 40%; in the mid‑stage, each accounts for 50%; in the late stage, reproductive growth comprises 60%–70%, while vegetative growth is only 30%–40%. Thus, it is essential to ensure an adequate area of photosynthetic leaves in the early stage, while later on, controlling plant vigor to promote fruit set and increase yield. Excessive vegetative growth inevitably impairs nutrient accumulation in the product, leads to substantial consumption of photosynthates, and results in lower yields.

Misconception No. 5 in Greenhouse Pepper Cultivation:

Frequent spraying leads to fewer diseases. Many vegetable growers, during the mid- to late stages of pepper cultivation, apply pesticides every 2–3 days, believing that more frequent applications slow the spread of diseases and that infrequent treatments will ruin the plants. In fact, during this period, frequent spraying not only disrupts the peppers’ normal carbohydrate synthesis but also hinders the production of phytoalexins, thereby weakening their disease resistance.

Solution:
① Accurately identify the disease and choose the right treatment; ideally, select formulations containing copper or zinc, which not only kill pathogens but also enhance the plant’s resistance to infection and promote crop growth.
② Improve the ecological environment; for plants with dense foliage and poor air circulation, thin out the leaves. ③ To prevent soil-borne pathogens, prioritize preventive fungicide applications during the seedling stage.

Misconception No. 6 in Greenhouse Pepper Cultivation:

More rotations mean more income. Many vegetable growers figure that once they’ve invested in a greenhouse, they shouldn’t leave the land fallow—so they plant a secondary crop right after the main one, or intercrop the main with the secondary. But the result is often that three times three equals nine, whereas two times five is only ten.

Solution:
① For overwintering, it is best to grow one crop per year; for spring and autumn crops, two crops per year are recommended. Old pepper plants can be regenerated to produce an additional harvest, and when prices are low, the plants should be uprooted and left to dry in the field.
② Each year, during the summer, set aside a period for deep tillage to expose the soil to the sun for sterilization, seal the greenhouse to eliminate pests, and allow the soil to mature; this approach significantly reduces problems with the main crop.