Light Sensor for Measuring Plant Light Levels

Hi everyone and welcome to my channel. Today’s Tuesday January 24th and we just had a close call with a nor’easter. Luckily it was warming up or it was all rain but fully smell we would have had some serious snow falls someplace we got over two inches of rain I think. The Boston area had over like 1.2 inches of rain. I definitely would have had to breakout or snow blower. Still have some gusts here. I just the coast to Cabrini had about 20 mile an hour gusts.

But I want to talk about in the light condition. I’ve been thinking about that in particular for the orchids that I have in the window. I don’t have don’t have any supplemental lighting for those and I’m just relying on the Sun that comes through the window but on days like today it’s really low light levels and it’s even lower inside the house.

Aiming for the email research we’ve had stretches of days where this is the extent of the Sun to solid overcast. So I’ve been thinking about getting some supplemental light lately. I’ve been curious as to exactly what the light levels are and what the requirements are for the orchids and I found online is that cat leaves in particular need about two to three thousand foot candles. I did find information that a day like today typically with overcast it’s about 100 foot candle that’s it. That’s a thousand Lux and direct sunlight is 10,000 foot candles and a hundred thousand lux. Just in direct full daylight of the thousand foot candles which is equivalent to 10,000 Lux and dusk is just ten foot candles or 100 lux.

So I like to see what the light level is on a day like today in the window for those orchids and also curious – how much light is being put out by those fluorescent lights I have over the citrus from the cellar. But the only way I can figure that out inside is by measuring it. So I went ahead and purchased a light meter.

Let’s go take a look at that so you can see here it’s little dark and gloomy here on the windowsill and I don’t think that’s enough light for these orchids. At least not enough light to produce some healthy growth and bloom.

So here’s a light meter. I bought it off of Amazon for 39.98. It’s a Digital Lux meter, Dr. Meter. Of course made in China, comes a little carrying case here. There this seems to be a couple of design philosophies. With these some the meter is built right in to the unit so it’s just all one piece and these you have from separate light detector attached by a cord to the meter. So you still have to use two hands to take a mobile type of measurement with this type of meter.

Let’s open it up take a look inside. Let me turn on a light, like I said it’s overcast today. We’ll talk in the house so let’s open this up here, warranty card and with the warranty is 24 hour response time 30-day money-back guarantee 12 months replacement warranty lifetime support, guarantee booklet.

I hope it’s self explanatory. So we’ve got the meter separate attached by this cord so you can go around and check different light. If maybe if you’re a photographer that’s important. I don’t like it. As I said some of them they just have the whole thing built into it and you just want something to have this type of design but there’s a little plastic cover like rubber bumper for the meter and I thought maybe this was returned because I had open this previously trying to figure out how the battery or if the battery was included. One is I just didn’t put the screw in so this is the cover and it was like this. Nice typical battery you get. One that you’ve never heard of,  Golite. At least I’ve never heard of that. Hope it doesn’t end up leaking into this.

Lets get this connected it’s your typical classic book covered in plastic. I have to get the plastic off of this first. Okay so we’ve got the battery stop measuring light levels. I’ll put that screw one later. Let see, be nice to pay attention you take things apart on they go back together again. Luckily there’s a towel there and a knotch for the cable. All right so power and you have the option here of changing from two different units here Lux which is currently on and foot-candles.

Please just take this cover off here pop up the sensor start measuring light. Wow, 71 Lux or less than 7 foot candles that’s less than dusk light. Let’s go check out the other window. So we look here we have what do we have. And so that’s odd, there’s scales on this unless this has to be perfectly flat that’s weird. For some reason that range, oh there is a range. Okay there is a range button because that seemed like it was going out of range it was maxing out and the display was watch. So how do we know what range were on. And press this I don’t see any in the calibration. There it is this up in the window says 10 X, 1 dot 100. So we have very low light levels that’s 250 Lux. If we want to look at foot candles that’s only 24 foot candles for these orchids, that’s not cutting it.

So I need from in-between over 2,000 foot candles is equivalent to 20,000 Lux. So yeah I’ve been looking at LED lighting for supplemental lights for these orchids. So now I know definitely you know verify here that light levels are way too low. So these Kathleen to produce some good growth and in flowers and I’ve been looking at some LED lights as a possibility for these orchids. I’m interested to see what the light levels are on the citrus. Okay so you can see here with the citrus this particular one. I do have some new growth here so it’s responding to this shop light that I installed with the four fluorescent lights. Let’s see what the light level is let’s see here range is 10 so we have over 2,600 Lux and foot candles that’s equivalent to about 240 foot candles. You can see that we’re back to Lux as x 10 scale. As we get closer up four inches away from the light or up to 10,000 and foot-candles that’s 1,000 foot candles.

So I would think for citrus if you can get as close to direct sunlight as possible that would be the best. That’s about a hundred thousand Lux or ten thousand foot candles and here I only have a thousand foot candles. No wonder these other lights here look at this I just notice the Shinoda orange here and South Orange has just loaded with buds. Let’s see what we have the light here should be similar to the other one. Let’s see range, it’s not auto-ranging so we have about 840 foot candles or 9,000 lux. So at least I know now what the levels are. And it’s pouring out again really dodge the bullet this time. If it was the smell we would have been buried.

Just wanted to add this real quick to compare it with the overcast day, here we have full Sun and have the curtain to the side there. So it’s just the frosted contact paper you can see the extent of the of the Sun falling on the kathleen’s as opposed to Phalaenopsis there. Let’s measure that, let’s measure that light level. Okay when I turn the sensor towards the Sun here that’s over 4000 jumping there get over 4000 foot candles. So the ones the one on the back here are already dropping down it’s just over 2,000 for candles. So like it says the cat leaves I think it’s supposed to get between two and three thousand. So it’s all showing there is adequate light coming through the window here for the Cavaliers. But if you have several days in a row with the overcast, that’s definitely not enough light.

So this is the citrusy earlier I have in the window here just through the glass and the light level here is over 5,000 foot candles and that’s over 50,000 lux.

So that’s the Doctor Meter Light Meter and now I know the light levels that I have on my orchids and on my citrus. So even if you have supplemental lighting and you’re just guessing. Probably good to have a meter to know for sure what your light levels are so you get healthy growth and healthy plants. So this is a New England Gardening checking out the light levels and probably needing to purchase maybe an LED light for the orchids.

Thanks for watching.