Greenhouse Clean-up and Sanitation

Introduction | Crop removal | Clean-up | Disinfection | New crop preparation | Ongoing sanitation procedures

Introduction
The greenhouse clean up process at the end of a cropping cycle is a very important step in a good IPM (integrated pest management) program. This step is an efficient low cost way to get rid of current pest and disease issues and to help prevent carry over in the new crop cycle.

Success requires a combination of crop removal, clean-up, disinfection, greenhouse preparation and sanitation procedures.

Crop removal
An important step prior to crop removal is to do an assessment of the current insect and disease problems in the crop. If you have presence of either diseases or insects implement a control program prior to crop removal to try eliminate these pests to reduce the risk of spread later when removing the crop debris. Turn off irrigation and reduce humidity to help dry down the plant material.

Plan your strategy for removal of plant material. If the material can be composted to local facilities arrange for disposal bins. If you are not going to move the material off-site, plan to excavate a hole to bury the crop debris which will be covered with soil later. Avoid piling crop debris near the greenhouse as these piles provide excellent opportunities for insects and diseases to move back into the greenhouse.

Remove all the plant material from the greenhouse paying extra attention to crop debris such as vines and leaves on wires, screens and pipes etc.

At this point you want to do an insecticide treatment to control insects currently in the greenhouse. Using fogging equipment with Dibrom will achieve the best results as the smoke will reach all the crevices and corners that liquid spray may not. Remember to increase the temperature to at least 20^oC and close all vents to seal off the greenhouse during this process to achieve maximum results.

Put up sticky traps in your greenhouses after doing an insecticide treatment to monitor if the insects have been eliminated and also to monitor any new occurrences of insects.

Clean-up
After removing the crop the irrigation lines need to be cleaned. First flush with fresh water, then flush with either nitric or phosphoric acid at a pH of 1.6-1.7 for 24 hours to get rid of any mineral precipitates in the lines (70% acid mixed at a rate of 1:50 with water). Then rinse again with fresh water to flush the acid from the lines. Soak dripper spikes or nozzles in acid solution to dissolve any mineral precipitates and rinse well with fresh water.

Power wash the entire structure with a food safe detergent solution to remove oily residues from the greenhouse and covering materials. Remember to wash down your headerhouse floors and your walkways as well.

Disinfection
Now you are ready to flush your lines and tanks with disinfectant using either 1% buffered bleach (pH 6.5-7.0) or hydrogen peroxide at a rate of 1000-3000 ppm. When done, flush with fresh water. Disinfect the drippers and nozzles with 10% bleach overnight and rinse with water when done.

Many greenhouse products are available for greenhouse disinfection. Some of the products on market are Virkon, Sanidate, Biosentry, C-Clean, TSP or 10% bleach. Ensure that you give the greenhouse time to dry between washing and sanitation in order to avoid any chemical reactions between the disinfectants and the detergent. Please follow safety recommendations and use required Personal Protective Equipment where applicable when applying these products and ensure you have adequate ventilation during application.

You headerhouse and all walkways should also be disinfected at the same time as your greenhouse structure is sanitized.

If you will be re-using totes, pots, trays tools equipment these should also be disinfected after cleaning all debris and organic matter.

New Crop Preparation
To prevent the contamination of your newly cleaned and disinfected greenhouse there are a few actions one can take to reduce your risk of pest and disease occurrence by installing footbaths/mats to disinfect shoes upon entry to greenhouse bays and using a 1% Virkon solution. If you have many compartments, place a footbath at each entry.

If a long period of time has passed since greenhouse cleanup, check your yellow sticky cards to see if you have the presence of insects and if you identify the presence of any problem pests you should fog the greenhouse again to eliminate them prior to starting your crop.

Ensure that any materials such as tools, carts, totes etc. have been disinfected before moving them into the greenhouse.

Examine or quarantine new plant materials being brought into the greenhouse and ensure they are pest or disease free.

Ongoing Sanitation Procedures
Control the movement of your staff so that if you have an disease infection or pest problem you do not spread it to other areas, This can be accomplished by restricting the access of the staff member who works in the contaminated area to that area. Or you can have your staff work in areas that have no infestations at the beginning of their shift and to the infected areas at the end of their shift. You can also have staff change clothing between bays or provide smocks or lab coats in each bay for staff to wear when entering that area.

You should control visitor access and if required have them wear lab coats or disposable coveralls when entering your facility to prevent the risk of pest or disease contamination.

An IPM monitoring program should be commenced at the start of your crop by installing sticky traps and doing a weekly count of insects. As well you need to do a visual inspection of your crop to check for symptoms of disease or virus and for insects that will not move to sticky traps such as aphids. Educate your staff on pest/disease identification as they will most likely see the symptoms first.

Initiate a biological/beneficial program as required.

For more information about the content of this document, contact Simone Dalpe.
This information published to the web on July 19, 2016.
Last Reviewed/Revised on July 16, 2018.