Problems with Protected Cultivation and their Solutions

Challenges of growing crops in the greenhouse are varied. Nowadays greenhouses or so-called controlled plant production are in vague. But it is a fact that problems are also associated with them. In order to grow vegetables in hot, humid conditions can be difficult for controlled environment growers whether growing in a greenhouse or a warehouse. 

The challenges of greenhouse growing in a hot climate are different than the challenges faced by growers in cooler regions. 

If one is using an evaporative cooling system to lower the temperature the problem can be solved. Suppose if the outside temperature is 110ºF, the temperature in the greenhouse can be lowered to 75ºF-80ºF (25ºC-27ºC) as long as the air is dry enough and water is available. The dryness can be a challenge, causing tip burn on sensitive crops. 

There are some parts in the country that deal with hot, humid summer conditions and very cold winters. There are regions where heat stress is a major issue for crops causing all kinds of physiological disorders including incomplete pollination and fruit ripening disorders. During the winter, heating and humidity can also be an issue. There is also an issue with low light levels so supplemental lighting is more important. 

Because of the limited optimum growing season in greenhouses using indoor productions systems makes more sense especially in adverse climatic conditions. 

Because of the interest in vertical farming prevalent nowadays it is very difficult to sustain greenhouses and maintain an optimum temperature all year round. An alternative for same can be warehouse production systems, including the use of LED lighting. 

Vegetable grafting 

Use grafting technology to reduce loss from soil-borne diseases and to increase yields can be an alternative to problems in greenhouses. Research on improving grafting methods and the handling of grafted plants so that they can be shipped long distances should be the main motive. Creating a simple tool for growers to schedule grafted plant production should be the focus. Having the grafted plants ready at exactly the same size is always a challenge for growers. The research group should work to develop a simple plant growth model based on environmental conditions to predict how many days are needed to finish a grafted crop.” 

A variety of plants, including tomato, watermelon, cucumber, eggplant, pepper and muskmelon can be used for the same.  There are many more crops that can use grafting technology to reduce loss from soil-borne diseases and to increase yields.

The grafting technology was originally developed for soil-based production, but greenhouse vegetable growers discovered that even though they are doing soilless production, using grafted plants can increase crop yields. In North America, greenhouse growers were the first group who started using grafting technology. The field growers are now more interested since they have fewer means to control the disease.  

Currently, tomato accounts for the majority of grafted plants in greenhouses. Increased tomato yields have been the driver for greenhouse growers to use grafted plants. Some greenhouse growers have been trialling grafted cucumbers and some research has shown that grafted eggplants can increase yields. 

Improving strawberry production 

Strawberry fruit production is not as productive as leafy greens or tomatoes in terms of dollars of return relative to the input of light. The interest should be in studying the increase in yields relative to the increase in light. What is the dollar value of that increase of yield by adding for example, 1 mole of light? Unless there is an improvement in lighting technology, it may not make sense to grow strawberries under supplemental lighting. 

One should like to come up with a smart lighting system to reduce the lighting cost based on the understanding of strawberry physiology and how plants are grown in a greenhouse. A person could reduce lighting energy use and costs quite a bit by doing that. Strawberries are physiologically unique in terms of light saturation and also in terms of the sink-and-source relationship of how much sugar can be translocated from the leaves so that the photosynthetic rate can be maximized.