Small fruit in crops grown in greenhouses is a sign of stress

Getting small fruit (peppers or tomatoes) is better than getting no fruit at all. However it can be frustrating when growing to achieve 140 g fruit and harvesting 60-80 g instead. Small pepper fruit can be the result of various factors such as:

• Poor pollination: the temperature may be too high during the critical period in the morning when pollination occurs. Use an industrial vibrator or use bee’s inside the greenhouse to improve pollination. The cheapest method is to walk each morning and hit the trellising wire with a stick while walking through the isles.
• Very high temperatures will limit fruit size and number, resulting in small fruit. Although peppers can tolerate high temperatures, the humidity should also be taken into account. Temperatures such as 30°C inside a greenhouse is acceptable if humidity is below 75%, however as soon as the humidity increases to 95%, hardly any plant will be able to grow properly.
• Too much shading will also cause small fruit in either peppers or tomatoes. Long spells of overcast conditions can also result in small fruit developing.
• A lack of water caused by blocked filters and to high EC. The irrigation cycles must be calibrated and checked to suit the texture of the growth medium. Make sure that the medium is not dry by the time the next cycle starts. Peppers are more susceptible to water stress than tomatoes or brinjals. Calibration is critical with these crops.  The ideal is to base irrigation cycles on sun radiation levels, this can easily be done with a computerized irrigation syste.