Ask the experts: Lighting

There are new things going on with greenhouse reflectors. Newer reflectors are now using a Miro material that is treated with a special process in order to achieve the maximum degree of reflection in the PAR (photosynthetic active radiation) spectrum. This treatment helps shift the spectrum so the plants get more PAR light for growth. Some reflectors also use a pebble-type finish to provide more surface area for greater reflection.

Perhaps you’re considering newer reflectors, or maybe you’re interested in just cleaning up your current ones, so the Greenhouse Management staff spoke with James Grouzos, sales engineer from P.L. Light Systems about caring for your reflectors.

If my reflectors are starting to look dirty, should I clean them or replace them?

Some of the larger lighting companies are offering light care packages. With these plans you are able to sign up for service agreements to get bulbs, capacitors and reflectors tested. These findings are then presented to customers in a detailed report, listing the components performance compared to new.

Using these tools you can decide if replacement or a simple cleaning will bring your system back up to optimal performance.
 

Is it expensive to replace reflectors?

No, on the contrary, it is actually cost effective.

If you lose 20 percent output on your bulb, 20 percent on your reflector and another 20 percent on your capacitor, your fixture is running at less than 50 percent of when it was new. That’s a huge loss.

If you’re running 100 1,000-watt fixtures at a reflector loss of 20 percent, and your kilowatt rate is 10 cents per hour, you’re wasting roughly $2.00 per hour or $12 per day on a six-hour cycle. If you add the other component losses, it could be $36.00 per day of wasted energy. This doesn’t even take into account that your plants will grow slower causing more loss of profit.

By signing up with light care agreement you can keep your fixtures performing at optimal levels. Your plants will sure notice the difference.
 

And how would I clean my reflectors?

Most of the time there is just surface dirt and grime on the reflectors. Dip the reflectors in a 1:100 vinegar: water solution to loosen the calcium and dirt buildup. You can scrub lightly with a nail brush or very fine bristle brush. Be careful not to scratch or damage the microscopic facets that help reflect the light.

Now rinse in plain water and do a final rinse in distilled water. This should remove the dirt and give you better reflectivity.

Remember, after awhile you will not be able to bring your reflectors back to 100 percent. Testing will show when they will actually need to be replaced. Replacing older reflectors with the newer MIRO ones can bring 7 percent of more light to your plants over the older style reflectors.