The 2017 growing season here in Lodi is now a wrap, but that doesn’t mean the work is finished. The time between crops can prove to be paramount to the success of the following season. Every grower should take the opportunity afforded by an empty house to perform yearly maintenance tasks, update equipment as needed, and clean and sanitize the greenhouse. 

This year proved to be challenging for us here at CropKing on the disease front. The warm wet season was conducive to outbreaks of botrytis and powdery mildew throughout our greenhouse. As such, we will be focusing the next two weeks on breaking down and cleaning the greenhouse in its entirety. Cleaning out a greenhouse is a relatively straightforward process.

• Removal of all plant materials
• Drain and flush all irrigation equipment
• Power wash all surfaces to remove organic deposits and debris
• Sanitize all surfaces with a chemical sanitizing agent.

Cleaning and sanitizing are two separate steps. Cleaning involves the removal of organic buildup and debris. This is best accomplished through the use of a power washer. Liquid soaps and detergents can be useful in helping with this process. There are commercial acid and alkaline cleaners available if you are facing a particularly fouled area.

The drain and feed lines should be flushed as well. If your drain line proves to be particularly full of scale, the use of a sewer jet power washer attachment can serve you well.

Irrigation lines and emitters can be cleaned by flushing an acid solution through the irrigation equipment. This will help dissolve any scaling buildup that might be reducing flow.

Once the greenhouse has been thoroughly scrubbed clean it is time to perform any needed maintenance. Here at CropKing, we will be replacing the film on our tomato house. The film has been installed for 4 years now and is showing a noticeable depreciation in light transmittance. Between crops is the perfect time to perform this task. We covered some of these seasonal considerations in an article published by Produce Grower here. 

We will also be checking the rest of the greenhouse over to perform any needed repairs or upgrades. 

Sanitizing the greenhouse is the very last thing you should do before starting a new crop. By waiting to the end to sanitize you ensure that any maintenance or improvement projects don’t contaminate your growing space. I prefer the use of peroxyacetic and hydrogen peroxide sanitizers such as Oxidate 2.0 and Sanidate 5.0 over bleach. These chemicals are very effective at eliminating a number of organisms while not leaving any residual component behind that would need rinsing. The use of chlorine bleach for whole house cleaning is best avoided as the bleach is corrosive to plastics and galvanized metals.  Quaternary ammonia products such as Green-Shield are also an attractive sanitizing agent. This chemical class will leave a residue though so be sure to thoroughly rinse any items that will actively come in contact with the plants or nutrient solution.

By cleaning and sanitizing our greenhouse now, we’ll be well prepared for 2018. In the next few weeks, we’ll outline some of the changes and trials we are looking forward to performing next year.