From time to time the gardener is blighted by dark brown patches appearing at the end of certain soft fruit. Tomatoes, peppers and aubergines all appear susceptible to a disease called Blossom End Rot.
The problem is caused by a lack of calcium in the fruits. It is usually avoided by keeping the growing medium consistently moist and not allowing it to dry out. It is mostly problematic when growing in pots where roots have limited growing space. Water is not necessarily held well but it is worth observing the fruit as it grows and checking on for discolouration. Keep the irrigation scheme going.
Automatic irrigation systems are ideal to maintain an appropriate level of moisture in the soil around the roots. It removes the need to water by hand. Mulching around the roots will also help to keep the moisture in.
Identifying Blossom End Rot
The rot starts as brownish patch which grows in size as the disease progresses at the blossom end of your fruit. Once the fruit is affected by this, there is nothing that can be done to reverse this issue. Best to remove affected produce and dispose of the fruit responsibly.
The other contributing factor is poor humidity. This factor affects all crops that are grown under cover. Prevent the disease from taking hold by making sure there is adequate ventilation passing through the structure to keep all the plants comfortable and healthy. Keep the vents and doors of the greenhouse open and then water in the evening when the weather is slightly cooler.