Plant Light of the Future

The LED desk lamp I just bought doesn’t look quite as jazzy as this one, but it cost only $20. Unfortunately, I'm having some problems with it. It doesn't maintain its maximum light as measured with a digital light meter.

It's a cool little lamp and would be great for keeping a desktop plant alive in cube culture. It's cordless and runs on 3 AAA batteries. There's no doubt in my mind that this is the light technology of the future. It could have a significant impact on the use of plants in our workspaces and elsewhere.

I'm going to contact the importer and see if the problem can be resolved. I'll let you know how it turns out.

Via: Inhabitat

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Lighted Room Divider

Jules at IKEAHacker posted photos of these lighted room dividers from IKEA. Unfortunately, it appears that IKEA doesn’t carry them any more. That’s too bad. There’s a need for products of this type.

I made a prototype vertical floor lamp from a Sonotube with a 4’ fluorescent fixture inside. I still have it and will photograph it when I find time.

In the past I’ve used fluorescent shop lights propped up vertically to maintain floor plant size Ficus benjamina trees. They were on timers so that the lights came on when the room was unoccupied. This technique works very well. I maintained Ficus trees in very dark rooms using these lamps with timers. All that’s needed is for someone to manufacture some well-designed fixtures.

I have several ideas for IKEA hacks to create furniture for displaying indoor plants. When I’m free of maintaining the lab, I plan to prototype them. There’s a need that no one is filling. It’s sad that there is simply no market leadership in the indoor plant market.

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LED Lighting Outlook

Hank Green (aka EcoGeek) answers a question about LEDs and offers his opinion about their future. LED lighting has the potential to make a significant impact on the use of plants in buildings.

Second, LEDs have a very high theoretical efficiency, but that doesn't mean they're all created equal. While incandescents and fluorescents have had all their kinks worked out, the materials that will go into creating LED bulbs haven't been settled yet. Engineers at GE, Philips and elsewhere are all slaving away trying to get the maximum light out of the least amount of power without sacrificing the quality of the light...all while decreasing costs.

But I guarantee you it'll be worth the wait. LEDs promise huge energy savings, high quality light, instant turn-on, and long-term lifespans while containing absolutely no toxic chemicals. What's my estimate for a $5-$10 120 watt equivalent LED bulb at Wal-Mart? Five years. Which, luckily, is right around when your CFLs will start burning out!

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Natural Light From a Tube

Photos - NW Natural Lighting

From the Natural Living blog.

Solatubes are a great addition to any green home. They are an innovative, tubular-shaped skylight. They are innovative because they do not require restructuring your home to install them. They take only about two hours for an unexperienced person to install. Since they are only 10-21 inches round, they can be installed between the beams of your home. Yet, they sure do brighten a room! If you install one in a bathroom with no windows, you will probably not have to turn on the lights at all during daylight hours, saving on energy.

In fact, your plants will thrive in a windowless room under the light provided by a Solatube. You can even have a traditional light for night time and a fan for a bathroom installed into the product, if you desire.

There are many more photos of Solatubes (and solar tubes) here.

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Twisty LED Lights

The future of LED indoor plant lighting for both display and plant growth is looking brighter every day.

Source: Inhabitat
Glide

Indoor Plant Lighting of the Future

This is an excerpt from a post about LED lighting from the archives of WorldChanging.com.

Solid-state lighting is indeed a big deal, however, for multiple reasons. One reason is not always appreciated-- the color gamut. LEDs offer far more colors than the usual fluorescent or incandescent emission spectra (and phosphor response spectra). LED light can be made to resemble natural sunlight. The impact on health for people who often work inside could be noticeable, and it could help indoor plants too.

LEDs are now at work in the Greenscaper Consumer Lab, not for growth lighting but for ambiance. On a recent trip to Costco, I spotted a set of 3 wireless LED puck lights for $14 (AAA batteries included). They do a nice job of providing mood lighting (either up lighting, or overhead light).

Being wireless, they are very convenient. The circle in the middle is the on-off switch (just press). Note the tilt of the puck light on the right (middle). The light heads swivel and pivot. Very cool!

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Compact Fluorescent Desklamp

Click to enlarge. Does it look like some creature from outer space is visiting this little Ficus tree? It’s a $10 desk lamp from Wal-Mart.

With a 27-watt (100-watt incandescent equivalent) compact fluorescent bulb, it provides more than enough light to keep a Ficus very happy on your workspace wherever it is. The range of light from the bottom to the top of the foliage is about 200 to 2000 foot-candles.

The bulb was too long for the lampshade so I extended the shade with a recycled food container. I spray painted the container flat black after cutting off the bottom half. It press fit inside the reflector so well that it didn’t need glue and it doesn’t get hot.

You can judge how it looks compared to these lamps from prior posts. It’s certainly less expensive.

Click to enlarge. This is a close-up of the compact fluorescent (CF) bulb. You can’t tell in the photo that it’s a “daylight” bulb providing natural white light. Most of the CF bulbs you see in stores are “warm light.” Warm light is yellow light that is comparable to the light from traditional incandescent bulbs.

Incidentally, it’s necessary to read the packaging very carefully to find “daylight” bulbs. The words are not prominently displayed and the bulbs are all the same color white.

I’ve gotten very used to the light from daylight bulbs and much prefer it. To my eye, it’s much more compatible with the green color of plants and it emulates natural outdoor light.

In my opinion, we have so much so-called “warm light” not because of preference but rather the technology of incandescent bulbs that leaves no choice.

Whichever you prefer, CF bulbs provide a choice, and more important they save significant energy.

Lux Your Plants

Light and water are essential requirements for healthy plants with light as the first priority. Without adequate light the plant will die and there's no need for water. This is about the most important first step you can take to provide adequate light and end Black Thumb Syndrome (BTS).

Use a light meter to measure the light in your indoor space to determine if you have enough for the plant(s) you wish to maintain.

Forget about window direction. Using window direction to judge light is advice usually given by outdoor gardeners and horticulturists with insufficient indoor plant experience. They typically don't understand the vast difference between indoor and outdoor "shade".

You may be familiar with foot-candle light measurement here in the U.S. Most of the world, however, measures light in lux, which makes more sense linguistically.

Whether you measure in lux or foot-candles do yourself and your plants a favor by buying a digital light meter. It’s a wise decision to buy one if you count the cost of your plants and your time.

Once you have a meter you’ll find that a difference of just one foot in location can mean the difference between a healthy and sick plant.

It's a waste of time and money to spend six months killing an indoor plant because there just wasn’t quite enough light. If you’re ecologically conscious, also think about the energy used to produce the plant that was wasted unnecessarily.

What does a digital light meter cost? Not too many years ago, you’d need to spend a hundred dollars or more.

Today you can buy a digital lux meter online on eBay for about $35 including shipping. You can now eliminate the importer and buy direct from sources in Asia. There are “Buy it Now” lux meters available directly from Shanghai, Hong Kong, and Tokyo. You can also bid on one from Sacramento, CA starting at $19.00 (without a case or light sensor cover).

My pick would be the one from Shanghai with a padded storage case and light sensor cover. I have very positive experience buying on eBay however no experience with this particular seller. I'd have no reluctance to buy one here but I already have six light meters.

Read the following about lux measurement and then look at the photo above. You'll then understand that a lux meter is really a combination lux and foot-candle meter. All you need do is move one decimal point to the left in your head.

The meter is reading 276 lux or about 27 foot-candles. That's close enough for indoor plant work.

It's not, however, enough light for the majority of indoor plants. So, don't put a plant there! That bit of information could easily save you the cost of the digital light meter.

Read a lot more about indoor plant light and lighting here.

Lux versus footcandle (from Wikipedia)

One footcandle = 10.76 lux. The footcandle is a non-SI unit of illuminance. Like the BTU, it is obsolete but it is still in fairly common use in the United States, particularly in construction-related engineering and in building codes. Because lux and footcandles are different units of the same quantity, it is perfectly valid to convert footcandles to lux and vice versa.

The name "footcandle" conveys "the illuminance cast on a surface by a one-candela source one foot away." As natural as this sounds, this style of name is now frowned upon, because the dimensional formula for the unit is not foot • candela, but candela/ft2. Some sources do however note that the "lux" can be thought of as a "meter-candle" (i.e. the illuminance cast on a surface by a one-candela source one meter away). A source that is farther away casts less illumination than one that is close, so one lux is less illuminance than one footcandle. Since illuminance follows the inverse-square law, and since one meter = 3.281 feet, one lux = 1/3.282 footcandle = 1/10.76 footcandle.

In practical applications, as when measuring room illumination, it is very difficult to measure illuminance more accurately than ±10%, and for many purposes it is quite sufficient to think of one footcandle as about ten lux.

On Your Desk for About $30 Complete

Click to enlarge. Here’s a sure cure for Black Thumb Syndrome (BTS) for about $30 complete—plant, clear glass bowl and compact fluorescent desk lamp. Wouldn’t this look nice on your workspace wherever it is? With this lamp, you don’t need to worry about having window light.

The natural light of this lamp will provide cheer for both you and your desktop plants during the coming winter. Do yourself a favor and ignore the advice to move them outside during the summer. It is simply bad advice.

Hurry to Costco. There’s a $5 rebate on an already affordable price for the 27-watt lamp. The output is equivalent to a 150-watt incandescent bulb. The net price is $21.99 after the rebate. Read more about the lamp here.

The lamp provides about 500 foot-candles, enough to support a flowering Spathiphyllum. I converted this new plant to expanded clay pebble sub-irrigation (aka hydroculture) in full bloom.

If you’re going to convert from soil to clay pebble media, I would recommend waiting until the flowers have expired. However, I wanted to photograph it in full flower. I’ve done this before and expect that the plant won’t even notice the hydroconversion.

You can even maintain high light requirement desktop trees like Ficus benjamina or Schefflera arboricola (dwarf Hawaiian Schefflera) with this lamp.

This is modern digital age indoor deskscaping. The plants need for light and water are met by modern methods. Anyone can cure Black Thumb Syndrome with this setup. Don’t let anyone tell you it won’t work.

If you have questions or need help, don’t hesitate to email me at bobhyland [at] insideplantslive.org

The Lowe’s Lamp

I was in my local Lowe’s store earlier this week and thought I’d look at the 27-watt floor lamp. I could not find it and asked for help. The lighting department staff could not find it either and didn’t know what it was. They found it on the computer all right but not on the shelves. They were most helpful but I didn’t have time to wait around while they tried to find it. I’ll stop back another day.

Incidentally, Lowe’s featured the lamp as a Father's Day item on the front page of a mail flier.

This illustrated to me how little is known about these lamps even by store personnel. Even the manufacturers do not understand that these are excellent plant lights. My thought was that if there were a demo lamp with signage in the houseplant department they would sell them out in no time.

Lowe's 27-Watt Floor Lamp

I noticed this lamp on the front page of a Lowe's flier today. It's also online for $39.

It appears to be equivalent to the specs on this floor lamp but you need to do your own due diligence. The specs online are rather sparse.

67" H x 11" D x 13" W Black Plastic Includes one 27-watt bulb

These natural light 27-watt fluorescent (equivalent to a 150-watt incandescent bulb) lamps are most beneficial for your plants and your eyes.

Adequate light is arguably the most important factor in maintaining healthy plants in buildings. Inadequate light leading to over watering is the leading cause of spindly plants and plant mortality.

Provide adequate light for your indoor plants and keep them inside all year. Moving them outside in the spring is not a good thing. Disregard the advice you read from outdoor gardeners and USDA extension program agents.

Two or three of these 27-watt fluorescent lamps could change a dark, dreary apartment into a bright and cheery environment for you and your plants. Consider a combination of floor and desktop models.

Natural Light on the Floor

Click to enlarge. This floor lamp uses a compact fluorescent bulb with the same specifications as the Lights of America Fluorex desklamps. The 27-watt compact fluorescent bulb is equivalent to a 150-watt incandescent bulb. It does not matter whether it’s a floor lamp or a desk lamp the amount of light generated is the same. It’s a function of the bulb not the fixture.

This is the first time I’ve seen a plant in a product photo of these 27-watt natural light lamps. Note however that this plant is too far away from the floor lamp to gain much if any benefit. The plant, chair, and light need to be located in close proximity to benefit the plant.

I continue to enjoy the natural light provided by the desk lamps. This is the best interior lighting I’ve experienced both for plants and for people. I’d encourage anyone to buy one…or two.

Desk Lamp Update

Click to enlarge.There is a new model of the Lights of America 27-watt compact fluorescent desk lamp now available. I previously reported on it in October 2005.

The new model is called a Sunlight Executive Desklamp. New features are a touch switch and convenience outlet. The one I bought from Costco is brushed metal with a cherry wood finish on the column. It cost about $29 including tax.

Were I the manager of a business, I'd authorize one of these lamps for every employee's desk. It would be a good human resouces decision, a good business decision. Studies have demonstrated the benefits of plants in a working environment. Many employee plants, however, are light starved and consequently over-watered leading to the propagation of fungus gnats and mold. Subirrigation coupled with one of these lamps would solve the problem at relatively low cost.

Get one of these lamps for your office at home. I now have three of them. They are without doubt the best desklamps I’ve seen for both plants and humans. The light is as close to natural light to my eyes as any I’ve experienced.

Home Depot is now carrying these lights and replacement bulbs. The one I saw in my local store was brushed nickel and black. The lamp didn’t have a price tag. There is also a floor model at about $60. The 27-watt bulb is the same on the desk and floor models. They also had the first version for about $20, which is what I paid at Costco.

The new executive desklamp is also available online at ESPLighting.com for about $35 plus shipping.

If you search online, you will find many of this style of compact fluorescent lamps with 13-watt bulbs. That may be fine for reading but I would highly recommend the 27-watt version (equivalent to a 150-watt incandescent bulb) for the best health of a desktop plant.

Following are approximate foot-candle readings at various distances from the bulb. You could keep a high light requirement plant such as a Ficus benjamina healthy with this lamp. It would probably provide enough light to maintain an orchid but not rebloom it. A long list of low light requirement plants would live happily under these lamps.

Approximate foot-candle readings
6” – 675 f-c
12” – 160 f-c
18” – 80 f-c

Recognize that the light level drops away as you move away from the center of the light zone.

Replacement bulbs
Home Depot – local store - $11.97 each
ESPLighting.com, Orange, CA – 2-pack $13.80 ($6.90 each) plus shipping
EFI – Energy Federation Incorporated, Westborough, MA - $6 each plus shipping

Tabletop Plant Light

Click to enlarge.This new desklamp is a winner. It’s elegant in design and functionality. It’s the first practical, affordable plant lamp I’ve seen. I’d rank it among the top ten technology advances for plants in buildings (has there been 10?).

It’s from Lights of America and incorporates Fluorex (compact fluorescent)technology. Some have used the Fluorex worklights for plant lighting. Worklights may be suitable for the basement or a dedicated plant room but not as an interior furnishing. This new desklamp can go anywhere.

Would you like to simulate how it adjusts? Place your elbow on your desk or tabletop. The lamp emulates the movement of your forearm and hand. It is very flexible as you will see when you buy one.

For some reason, the new desklamp is not on the Lights of America website.

This information is direct from the box graphics.

Sun Light Desklamp

• Natural Full Spectrum Lighting
Simulates Daylight Inside
• Saves Energy
150 Watt Light Output Uses 27 Watts of Energy
• Brilliant White Light
FLUOREX Technology Creates Sharper Images and Reduces Eyestrain
• Long Lasting and Cool Operation
Fluorescent Lamp Last Up To 13 Times Longer and Produces 80% Less Heat Than a Regular Light Bulb
• The Sun Will Always Shine!
The SUNLIGHT lamp brings many of the benefits of natural daylight for glare-free full-spectrum lighting that’s perfect for a variety of indoor activities such as reading, writing and sewing.

It’s interesting to note that nowhere does it mention, or display a photo highlighting it’s use to maintain plants in buildings. Such is the current low level of knowledge and awareness of the subject.

I bought the lamp at Costco for just under $20. You can also buy it online. Sams Club has it for the same price plus shipping. You can also find it on eBay.

New Light on Meters

Seemingly unnoticed by interior horticulturists is that we’re in the digital age. It was somewhat of a shock to read yet another recommendation for the GE foot-candle light meter. This is as up to date as the 8-track player in your grandmother's Oldsmobile is. Do not buy a GE analog meter or this analog meter.

This is a previous post about buying a digital/lux meter on eBay. You won't find any better selection or prices than these for digital light meters suitable for measuring light for plants in buildings.

The options range from a Lux meter at only $20 to a combination Lux/Foot-candle meter for just $50. It's a good idea to buy a meter with a carrying case.

How Low Is Low Light?

If we posted links to all of the outdoor gardening advice columns we read with misinformation about indoor plant care we'd use up our bandwidth in a hurry. This well intended article, however, has some significant misinformation worth highlighting, pun intended.

The author, an extension educator for horticulture, demonstrates a lack of understanding about light measurement inside buildings. He’s not alone. We read misinformation of this type daily.

Householders commonly move houseplants outdoors during the summer even though it's a bad idea. If they’re located in a shady location the natural light is in the range of 3,000 to 5,000 foot-candles. In the fall, they are abruptly moved back inside and plunged into a low light interior that may range from 50 to 500 foot-candles if in a window.

Doing the math, the reduction in light level is typically in the range of 80 to 99 percent. Would you lose weight in a hurry if 80 to 99 percent of your food intake was reduced in a day? This might convey an idea of the shock the plants are experiencing.

The author erroneously cites a reduction of “as much as 50 percent” which is a gross understatement. Further, the amount of light that houseplants receive in their Florida greenhouse is more like 20 to 30 times the light they receive in a Nebraska living room, not “two to three times”. The point here is that the article understates the degree of difficulty involved in bringing houseplants in from their so-called 'summer vacation'.

More than likely the author has never had a need to use a foot-candle light meter and perhaps doesn’t even know what it is. Outdoor gardeners, including professional horticulturists can get by without a foot-candle light meter. The range of outdoor light is much more forgiving.

The range of light indoors is not forgiving. The margin of error is small and the cost may be loss of a valuable plant. Light for photosynthesis is critical to an indoor plants health and survival. Most symptoms of poor health are caused by light starvation. Water and plant food only aggravate the condition.

The article illustrates the need for extension horticulturists to learn the true facts about interior plant maintenance including foot-candle meters and measured sub-irrigation (MSi), before writing about the subject.

We observe that it is poorly understood within the extension and Master Gardener programs that indoor plant care isn't merely another form of outdoor gardening or greenhouse growing. It is distinctly different from either of them.

Excerpt: Over the past month or so, homeowners have started to move many of their houseplants indoors after the plants have been set outside all summer. Well, simply moving plants inside can cut back on their sunlight supply by as much as 50 percent. Also, many houseplants sold in the Midwest actually were grown in Florida, where they received two to three times the amount of sunlight they would typically get in a Nebraska living room.

The Real Killer Is...

We extol the benefits of sub-irrigation because it is justifiable. However, if the light is insufficient no watering method will save an indoor plant from death. Websites and houseplant books frequently cite over-watering as the primary cause of houseplant mortality.

It is our experience, however, that light is the most critical factor. If over watering is a gun that kills houseplants, the trigger is insufficient light. It is worth the time to study this chart before installing any plant indoors. And…get your hands on a digital foot-candle (or lux) light meter any way you can.

Let There Be Indoor Plants - And Better Lighting

The only thing missing is the Rhapis palm. We enjoyed this article. Barbara has the right idea.

However, we need better lighting options to support the creative ideas of professional interior designers...and the life of the plants of course.

 
 

Excerpt: There needs to be a place in our lives where we can close the door and relax. I like to think of our homes (or perhaps for some only our bedrooms) as an oasis, a sanctuary, a place to rest and renew ourselves so we can go forth again.

It’s very soothing to bring nature into your home at whatever level you can. If you can maintain a few green plants, large or small, it will do wonders for your space. Of course, fresh flowers, even if it’s a single flower in a bud vase, are uplifting. Flowering plants are a good deal financially because their flowers usually last longer than cut flowers.

Studies have shown that people feel better around plants. Something within in us craves nature and is healed and strengthened by it.

Indoor Plant Lighting

The author makes a case for buying an indoor plant lighting setup. This is a good path to take for those interested in indoor gardening involving small plants and seed starting.

Our point of view, however, is indoor plants would be a more typical part of interior furnishings if there were light fixtures designed to support them. Here is what we accomplished with one commonly available fluorescent fixture.

The stereotypical solution for ‘indoor gardening’ has been overhead light, typically installed on a rather expensive ‘light stand’. The light from a window is not overhead it is side light. We have yet to find a vertical or columnar plant light. We have supported the maintenance of a floor-standing Ficus benjamina tree with just one vertical fluorescent fixture.

Excerpt: I can never figure out why a population will spend hundreds of dollars on average for equipment and supplies to support annuals that last three months but be so stingy when it comes to buying a simple light setup to grow indoor plants for a season three times as long. The loyal reader knows I think all Alaska homes should have at least a simple shop fixture with two fluorescent bulbs and a timer for growing plants indoors during winter.

No Window In Your SOHO?

Click to enlarge.

Perhaps your home office doesn’t have a window and you would like to have some decorative plants.

No, you do not need to call a contractor. Just create a "window" with a fluorescent light. Look at the photo and think “replica window” rather than shelf.

This is not a staged photo. These plants live and grow here. This is their permanent home.

There are two phases of “replica window” light. This is the “moonlight” phase. Please overlook our amateur photography. We shot during the day with both natural and artificial light so that you can see the details. The "moonlight" is supplied by one low cost incandescent up-light.

The “daylight” phase is horticultural light supplied by one 4-foot fluorescent light. This one has a diamond pattern plastic diffuser. It could also be an ordinary shop light with no diffuser.

Both lamps are connected to timers so there’s no hassle involved in switching from “moonlight” to “daylight”. The light switches automatically.

Water is supplied by sub-irrigation. There is no need for special "plant lights". This is not indoor gardening but rather interior plant display for decorative purposes and to bring a bit of the outdoors inside.

Offer: Send us digital photos of your office and we will be pleased to help you design a "replica window".

Shared Light Meter

A digital foot-candle or lux light meter now costs less than a quality chef’s knife. We firmly believe it is a wise expenditure for anyone serious about maintaining quality inside plants. It could pay for itself by saving the replacement cost of a single floor plant such as a Kentia or Rhapis palm.

For those looking to economize there are solutions that are far better than guessing at light levels and putting their plants at risk.

Consider sharing the cost. A light meter is typically not in constant use. The primary need is in locating a plant upon acquisition. Here are some ideas about group use of a meter.

Share the cost and use within a family, garden club, condo or co-op association. If you live in a multi-unit apartment, recommend that the manager buy one for tenant use. It would be a valuable renter amenity at very low cost.

Campus organizations such as resident student associations, sororities and fraternities could own one for the benefit of members. College students new to indoor plant care would benefit greatly from spotting plants with a light meter and learning how to sub-irrigate.

Individual use of these group meters should probably involve retention of a deposit to protect against loss or damage.

Your ideas about sharing the cost would benefit everyone. Please post them by clicking on "Comments" below.

Photographic Meters To Measure Plant Light

There is much advice about using a photographic meter to measure plant light on extension/master gardener websites and in houseplant books. They typically provide a method to convert f-stops to foot-candles since the majority of photographic meters don’t read out in foot-candles.

This is a poor substitute for using a foot-candle or lux meter.

Photographic meters and those built into cameras are reflective meters. They measure the light that reflects from the object or subject (in this case plants). That is not what we are interested in.

We want to know how much light the plant is receiving rather than reflecting. That’s what foot-candle or lux meters measure. They are called incident meters and measure the light falling on the subject. Your plants will love you for using one.

O Say Can You See?

Do you have a digital foot-candle or lux light meter so you can see if your plants can "see"?

With the coming of the digital age, meters for precision measurement of inside plant light have never been as affordable and feature rich. I believe from long experience that a foot-candle/lux light meter is the most important investment anyone caring for inside plants can make, either on the job or at home.

Following are recommendations based on a study of the current market. To my surprise, I found some very good values on eBay. These digital light meters now cost less than most kitchen gadgets.

Buy a digital meter reading either foot-candles or lux or switchable to display either. Other desirable features are a protective carrying case and a hold button.

I would not recommend an analog foot-candle meter. This is obsolete technology. There is an analog meter in the $25-30 range widely available on the web. I have one and would not recommend it.

I also do not endorse the G.E. analog meter that many interior plantscapers still recommend. We used them in the '70s when I was in the interior plantscaping business. One significant bump and these meters were kaput.

We then bought a professional quality Spectra f.c. meter for about $150. It measures up to 30,000 f.c. and is housed in a durable protective case. I still have it but don't use it because a digital meter is much easier to use. It's replacement cost would be over $300.

For inside plant purposes I find more value in this meter I bought on eBay.

Best features, Best buy – C.E.M. DT-1301 – Features:
Switchable to read out in either Foot-candles or Lux
Hold button
Automatic shut-off
Built-in low battery indicator
Reads up to 50,000 lux
Padded carrying case with wrist strap
Snap-on light sensor cover
$49 + shipping

The same meter with lux readout only and no hold button is about $10 less.

I have also seen a digital lux meter on eBay for about $25.

If you’re not familiar, lux is the metric equivalent for foot-candles. One lux = 0.09290304 foot-candles. That’s close enough for our purposes to say 10 lux = 1 footcandle. When reading a lux meter all you have to do is move one decimal point to the left to convert to foot-candles. When you read 500 lux it is approximately 50 foot-candles.

It appears that all of the economical digital lux and foot-candles meters are Asian imports. I bought an Extech 401027 Pocket Foot-candle meter for $69 without a protective case. I inspected it and found that it was made in Taiwan by Lutron.

The Plants-In-Buildings website recommends using a light meter. This is an informative, well-written document (PDF file) worth reading and printing out.

Excerpt: The only way to accurately measure light is to use a light meter. NEVER rely on your eyes and your judgement about the light levels in a room, because your eyes adapt very quickly. No matter how much experience you have in specifying plants, you can never trust your eyes alone when making a decision about light levels.

I found the same Lux meter shown on the Plants-In-Buildings website online at FamilyDefense.com for $46.95 with a carrying case. It too is made by Lutron.

A New Meaning For The Word Shade

This chart (click on it twice for a readable copy) shows a comparison of outdoor, production and typical indoor ambient lighting. It puts in perspective how inappropriate the word "shade" is when applied to inside plant lighting. Outdoor gardening terms are simply inappropriate when applied to inside plant care.

Adequate light is the most critical requirement for inside plant health and longevity. Many plants die because of inadequate light and the caretaker erroneously places blame on watering practices.

New affordable digital foot-candle light meters will pay for themselves many times over in inside plant replacement costs over the life of the meter.

More Light Please…And Hold The Water, Thank you.

Popular opinion is that overwatering is the primary reason for poor indoor plant health. Many years of problem diagnosis coupled with experiments in my inside plants lab, however reveal the “back story”.

Behind the watering problem is usually a light shortage problem. Most often, the shortage is unrecognized because of the primitive means used to measure it.

Would you see a doctor who doesn’t use a stethoscope to check your heart or cuff to check your blood pressure? Would you take your dog or cat to a vet who doesn’t have an ophthalmoscope or otoscope? Would you check your sick baby’s temperature with your finger? Do you cook without measuring cups and spoons? Hopefully the answers are no.

Why then do houseplant books and indoor plant care websites advise readers to gauge light by window direction? How primitive is that? Why do they use vague immeasureable terms such as diffused, indirect, bright, shady, filtered, intense and reflected to describe it?

This is the digital age of the 21st century. It baffles us that houseplant book authors and website writers are still so techno apathetic or technophobic that they don’t advise buying a foot-candle light meter.

You can do the same searches I do and you’ll read the same pathetic advice. “Oh well, my doctor doesn’t have a stethoscope. Too bad, I’ll just suffer and die.”

Use of digital foot-candle light meters would save the lives of an untold number of houseplants. If houseplants could talk, there would be a nationwide houseplants rights movement screaming with indignation about the poor treatment of its members.

Look for the next peaceful demonstration in your town.

More Light Please…And Hold The Water, Thank you.

Popular opinion is that overwatering is the primary reason for poor indoor plant health. Many years of problem diagnosis coupled with experiments in my inside plants lab, however reveal the “back story”.

Behind the watering problem is usually a light shortage problem. Most often, the shortage is unrecognized because of the primitive means used to measure it.

Would you see a doctor who doesn’t use a stethoscope to check your heart or cuff to check your blood pressure? Would you take your dog or cat to a vet who doesn’t have an ophthalmoscope or otoscope? Would you check your sick baby’s temperature with your finger? Do you cook without measuring cups and spoons? Hopefully the answers are no.

Why then do houseplant books and indoor plant care websites advise readers to gauge light by window direction? How primitive is that? Why do they use vague immeasureable terms such as diffused, indirect, bright, shady, filtered, intense and reflected to describe it?

This is the digital age of the 21st century. It baffles us that houseplant book authors and website writers are still so techno apathetic or technophobic that they don’t advise buying a foot-candle light meter.

You can do the same searches I do and you’ll read the same pathetic advice. “Oh well, my doctor doesn’t have a stethoscope. Too bad, I’ll just suffer and die.”

Use of digital foot-candle light meters would save the lives of an untold number of houseplants. If houseplants could talk, there would be a nationwide houseplants rights movement screaming with indignation about the poor treatment of its members.

Look for the next peaceful demonstration in your town.