Neophilia
Noun. A strong affinity for novelty. Neophiles (also known as “Neophiliacs”) adapt rapidly to changes and loathe tradition, repetition, and routines.

Here Comes the Sun

Sunlight is the first order of life – the energy that drives the life systems of our planet, from humans to plankton. So it follows that the ‘heart’ of your indoor garden is the grow light. After all, its purpose is to provide the incident energy required by your plants to grow and bloom: to synthesize the sun. The grow light is the motor of photosynthesis in the indoor garden, driving all other plant processes.

Today, the majority of indoor gardeners in North America use 1000 Watt High Pressure Sodium (HPS) lamps to light their plants and many growers still use magnetic ballasts. It may surprise you to learn that this technology has been around in more or less its current form for over 30 years. In other disciplines, most notably computing, a great deal has changed during this time. Can you imagine buying a personal computer today that even closely resembled that which was available thirty years ago? In 1980 the latest and greatest microcomputer boasted a measly 16kB of RAM (barely enough to store a ringtone these days) and a 5-inch CRT display. If you’re not abreast with the current state of computing technology, then consider this: a megabyte of storage would have set you back over $6,000 in 1980. Today, one hundred times this amount can be purchased for under a dollar. Things have moved on.

So what drove this huge amount of innovation? Essentially, nothing more than a heady mix of human ingenuity and rampant consumerism. That is, we all went crazy about computers and demanded more and more. In just a few decades they went from being arcane university research projects to being suffused into almost every part of our mainstream culture. Will the recent and dramatic rise in the popularity of indoor gardening serve as a similar catalyst for technological development in the field of indoor horticultural lighting? We certainly hope so.

New Paradigms of Lighting for Plants

If computers are measured in terms of processor speed and memory capacity, what is the equivalent set of metrics for the performance of a grow light? Okay, okay, obviously a grow light should make things grow. And the plants we want to grow have all evolved over millions of years to best exploit the solar energy generated by the Sun. So we don’t need a Ph.D. in Photobiology to assert that the Sun is the only benchmark we need when it comes to producing artificial light for plants.

That’s a point worth restating. We’re talking about light for plants here, not for humans. It’s very important that we de-personify both our plants and, for that matter, our grow lights. Lumens measure general light intensity for the human eye, not the photo-systems in the leaf. What we perceive as a single color is actually a combination of many different wavelengths of light.

How plants relate to light is more like hearing would be for humans: by frequency. Sunlight contains a ‘full spectrum’ of different frequencies. PAR light, nanometers, and other older references for light can’t be used as a reference for frequency; nanometers and frequencies are inversely related (backwards) to each other. Frequency means it’s more about the energy that plants really need, and nanometers is more about what’s best for people to understand.

The "Plant Sensitivity Curve" shows photosynthetic response to light at various wavelengths. (X axis = WAVELENGTH (nm); Y axis = "SENSITIVITY") Photo credit: Chameleon Grow Systems.

One of the primary reasons that HPS light was adopted by indoor gardeners is a NASA study produced over 20 years ago that basically stated: “Plants are efficient at using red light.” You have probably seen the spectral distribution charts on some HPS lamp packaging showing the peaks in spectral output. However, plants are efficient at using red light because, of all the colors in the spectrum that shine on the Earth from the Sun, red light has the least amount of energy. Photobiologists refer to this in terms of “electron volts per photon.” You can excite the cells of a solar panel with a violet light that has 3.1 electron volts per photon. But shining red light that has only 1.7 volts per photon on a solar panel is not sufficient to excite the cells. So, just because plants are efficient in using the low amounts of energy in the red parts of sunlight, it doesn’t necessarily mean that the best lighting for plants is high in the red parts of the spectrum. We don’t need to bombard our plants with red light. Plants require all the colors of the light spectrum as they utilize these different parts in different ways.

Another reason HPS light is used by indoor gardeners is to imitate the commercial greenhouse growers who use HPS for daylight supplementation. However, it’s important to note that, in greenhouses, HPS is used in addition to the blue light of natural daylight. It’s clearly a different ballgame to grow indoors using only artificial light, and we should treat it as such.

Who Turned Up The Heat?

So what’s an indoor gardener to do? We want to give our gardens lots of light – especially if we are growing light-loving varieties such as tomatoes and capsicums. HPS lamps output a lot of light, but in limited parts of the spectrum. They also produce a LOT of heat in the infrared part of the spectrum. And, as we all know, unless you’re growing indoors in Alaska, excessive heat is the nemesis of the indoor gardener. Surely there has to be a better way to grow indoors? Think of all those kilowatts of energy used to power grow lights, and all the kilowatts of energy used to power air conditioners, chillers and fans to remove the heat they generate! What technology exists to give our plants all the light they need indoors without creating other problems that require energy-intensive solutions? Do we need to improve current technology or go back to the drawing board? Do we need new lamps? New ballasts? New reflectors? New light movers? These are all very important questions.

Before we embark on our preview of alternative grow light technologies, please bear in mind that some of these technologies are further away from being stocked in your local grow store than others. Research and development is happening all the time, and this work is not confined to universities – real growers (albeit super enthusiastic hobbyists) are involved too. Right now, some of these technologies, for a variety of reasons, are less accessible than others. But things will change, if we drive that change. Remember, it was possible to buy a 1GB hard drive in 1980 – it was just the size of a refrigerator, weighed 550 pounds and cost $40,000! Today a hard drive 500 times that size will comfortably slip into your pocket … if there’s room! (It will only set you back $70.)

Now put yourself in the shoes of an IT enthusiast in the ‘80s. Are we at an equivalent point on the technology/accessibility curve for indoor garden lighting? If so, these are indeed exciting times! Okay, that’s quite enough preamble! Let’s take a look at the contenders …

Light – A Crash Course

The human eye is most sensitive to a yellowish green color. But what seems 'bright' to us is not what plants respond best to. Photo credit: Chameleon Grow Systems.

In one sense, light can be thought of as electromagnetic radiation, like radio waves, microwaves waves, X rays and gamma radiation. What we refer to as ‘visible light’ is simply the radiation that we can sense with our eyes. The average human eye will respond to wavelengths from about 380 to 750 nanometers. We perceive light as colors, with our maximum sensitivity at around 555 nm, in the green region of the optical spectrum. Light with a wavelength of 380-450 nm is perceived as violet. As the wavelengths become shorter it becomes ultraviolet (UV). At the other end of the visible light scale, wavelengths of 620-750 nm are perceived as red. As the wavelengths become longer (infrared) we perceive this electromagnetic radiation as heat, rather than light.

Light can also be conceived as a stream of light particles, called photons. One method to calculate the intensity of an artificial plant light source is to count the number of photons that hit a leaf per second. The unit for this calculation is “micromoles per second” (μmol/sec). Some growers reference the Photosynthetic Photon Flux (PPF) – just the photons that are between 400 and 700 nm. This is clearly a more relevant way of measuring light intensity for plants than, say, lumens, but it should still only be treated as an indicator. When all has been said and done, we’re trying to establish the quantity of usable light that hits the leaves of our plants.

Spectral Distribution

The distribution of energy in the lamp on the frequency spectrum is called the Spectral Distribution. The Sun has a full, continuous spectrum – and that’s what we’re aiming for too with our grow lights. The ideal grow light efficiently transforms electricity into the maximum amount of usable light energy (for the plants), with as little heat (infrared) as possible. Other factors to consider are lamp life and depreciation, and, of course, cost!

Inverse Square Law

Remember, if you double the distance between a leaf and your artificial light source, the amount of energy that hits the leaf is divided by FOUR. Stated another way, when you double the distance from the light source you lose 75% of the light energy from the light source. So when we talk about how much ‘usable light’ a grow light puts out, we need to consider environmental factors too – namely heat! Experienced indoor growers shoot for a temperature of around 80-82°F around the canopy of their plants in a CO2 enriched environment, slightly less for atmospheric CO2 levels. It’s important that we evaluate the potential of any grow light in the “real world,” and not just the isolated data of manufacturers’ technical specification charts.

Sulfur Plasma

Plasma International's Sulfur Plasma grow light. Photo credit: Clive Wing & Boris Lutterbach and Aad Baar.

Plasma International, a British/German company, has developed a grow light based on sulfur plasma technology. The lamp and magnetron unit is an electrode-less lamp that includes an evacuated quartz bulb partly backfilled with argon and with a little sulfur, plus a source of microwave power, a magnetron, for exciting a ball of plasma within the bulb. The lamps themselves are manufactured in Germany and can be powered by any 400W to 1400W Plasma Lighting System. The lamp produces almost no ultraviolet light and just a little infrared. It delivers a full and continuous spectrum (which means there are no troughs or missing/lacking color content). Full spectrum lighting is regarded as crucial for healthy plant development because it’s what plants have evolved for millions of years to exploit.

Wageningen University in the Netherlands has been using Plasma International’s Sulfur Plasma lamp to research simulating daylight in an indoor environment. Researchers had to shine the incredibly powerful light indirectly at cucumber cuttings through mirrors and filters. The tests, conducted in a climate-controlled room, showed that young cucumber plants grew much better then under HPS. Researchers believe this is due to the color of the light and its ability to influence the shape of the plant. At the right light color, the young plant captures light energy far more easily.

The cucumber plants grew more than 60% faster than those grown under HPS, and more than 120% better than those grown under compact fluorescents! There was also a marked increase in branching and larger leaves. The first results (released September 2009) also showed that the specially-created artificial sunlight spectrum made the young cucumber plants 64% heavier than those grown under HPS (SON-T) light, at equal light strength.

Plasma International’s lamp draws 1300W from the mains and delivers 1000W to the bulb. It is dimmable down to between 10-40% depending on which bulb is being used. The moving parts inside the lamp are guaranteed for 100,000 hours of use – this movement, the manufacturers claim, gives greater control over the plasmoid. They also claim that they can quite easily alter the mix of the bulb and adjust the spectral output to specific applications. To date, Plasma International has developed one lamp for vegetative growth and another for flowering. The lamps produce less than half the infrared heat per watt compared to HPS or Metal Halide.

The lamp comes as two boxes. Each box is 9” x 6.6” x 6.6” in size. One box contains the plasma-i-tron and the other is the power supply. The lamp can easily cover the same area as a 1000W HPS but, because of the reduced heat, it could be positioned closer to plants.

More information: www.plasma-i.com
Time to market: 1-2 years.
Cost: Currently only available for research purposes. Expect to pay upwards of $3,500 per unit.

Light Emitting Plasma – LIFI

Luxim's lightweight Light Emitting Plasma Emitter.

Luxim Corporation in California has developed a solid state light emitting plasma – it uses metal halides and argon, not sulfur. It uses no electrodes and draws 266 watts. Their latest model, announced in February 2010, is the LIFI-STA-41-02. Luxim only produces the light unit. It is up to companies further down the ‘technological food chain’ to develop specialized appliances for their specific market, such as TVs, theatrical lighting, healthcare, horticulture, etc. Crucially, the LIFI Plasma light was NOT invented to grow plants. The spectrum is still lacking a lot of red.

LUXIM is researching how to use different metal halides in the plasma cell in order to create a better spectrum for plant growth. Until they, or somebody else, figures this out, various companies in Europe and North America are experimenting with LEDs in an effort to correct the spectrum. However, whether this is actually possible or not remains a bone of considerable contention. One such example is Chameleon™ Grow Systems in Florida. They have developed the Solar Genesis VI (due for release later this year) which houses two LIFI plasma units and banks of high output LEDs. Infrared (IR) radiation from the light is minimal.

The Solar Genesis VI spectral output compared with an HPS, overlaid on plant light sensitivity. Photo credit: Chameleon Grow Systems.

The internal ballast has 91-93% conversion efficiency and the lamp life is rated at an incredible 50,000 hours (11.5 years) with no replacement every 9-12 months necessary.

The Solar Genesis VI supplements two Luxim 266 watt LEP units with four banks of high power LEDs. Photo credit: Chameleon Grow Systems.

Tech Stats: LIFI-STA-41-01
Emitter Length: 72.9 mm
Emitter Diameter: 116 mm
Driver Unit L × W × H: 193 × 85 × 32 mm
Rated Average Life: 30,000 hours
Total Initial Lumens: 15,000 lumens
Typical Turn-on time: 30 seconds
CCT: 5800 K
CRI: 94
Dimming Range: 20-100%
Nominal AC Power @ 277v 266 watts

More information: www.luxim.com www.chameleongrowsystems.com
Time to market: 3-6 months
Cost: $7,000 per unit for Solar Genesis VI

Other Technologies

Phillips HPS 400V

Lumatek's new ballast will enable growers to run highly efficient 400V lamps on 230V power.

Lumatek is in the process of developing a new 400V professional ballast that drives the professional Phillips HPS 400V lamp, but runs on normal 230V. Gavita, a leading European horticultural lighting company, has teamed up with Lumatek to develop and bring their products to the indoor gardening market. Industry insiders concur that this allegiance is great news for growers!

The 400V bulb, which is more efficient, performs more consistently and lasts longer – and it has an enhanced spectrum. Even better: it was built specifically to run on electronic ballasts.

Time to market: 3-6 months
Cost: To be announced
More information: http://tinyurl.com/yjzx2dk (pdf)

SunPulse® Pulse Start Metal Halide

SunPulse® bulbs were specifically designed to produce the true photochemical reactions plants need to make the maximum amount of photosynthesis and produce the most chlorophyll. This is a very important point. SunPulse® bulbs were made for plants. They were designed by Gerald Garrison – and if that name sounds familiar, you may remember he was featured on the cover of Urban Garden Magazine 003 in relation to his indoor food production facilities in February 2009.

The original SunPulse® digital bulbs, the first digital bulbs to ever be introduced, are made in four unique Kelvin colors: 3k, 4k, 6.4k and 10k. The lamps’ wattages range from 100 to 1000.

SunPulse Pulse Start Metal Halide Lamps were designed for specifically for plant growth.

Central to their lighting model is a photosynthesis delivery system which houses and rotates multiple lamps (of different Kelvin temperatures) over the plants, to provide full spectrum lighting. A lighting schedule is located on every bulb box which outlines when to use each particular bulb, as well as suggestions for those who aren’t budgeted for four bulbs per fixture.

SunPulse’s 1000w Commercial Grade bulbs were originally designed exclusively for commercial food production facilities, but are now being made available to growers everywhere for the first time. The Commercial Grade bulbs come in three proprietary colors: 2.8k (fruiting/flowering), 5.7k (full spectrum) and 10k (ripening). Commercial greenhouses around the world are already enjoying the benefits of the greater efficiencies and color rendering made possible by this series of bulbs. The Commercial Grade lamps’ high-temperature tolerances, rugged design and top quality components are the perfect choice for full-scale production facilities and now are available for smaller producers as well.

Time to market: Available now.
Cost: 1600W 4 x 400W (3K, 4K, 6.4K and 10K) Spinning Light Complete System – $1,950
More information: www.sunpulselamps.com and www.lifelighttec.com

Want to know more about these or any other horticultural lighting technology? Fire your questions at will by posting a comment below!

Everest shares some time-honored heuristics to help beginner growers increase the productivity of their indoor gardens.

1.) Reduce Your Concentration!

Hydroponic growers adjust the pH of their nutrient solution to around 5.8 to 6.2 – this provides the best accessibility to the widest range of nutritional elements.  pH adjuster products are sold in grow stores in concentrated liquid (sometimes powder) form.  However, some growers get lazy and add this stuff neat (undiluted) to their nutrient solution.  This causes nutritional elements to precipitate out of the solution and therefore become unavailable to your plants.  To avoid this, make up a dilute solution of your pH adjusters – 1 part pH adjuster to 100 parts water – and use this instead.  The weakened concentration of your pH up or down will enable you to safely adjust the pH of your nutrient solution without damaging your nutrients!

2.) So Near, So Far …

More light = more yield … but only to a point!  In fact, grow lights can represent a mixed blessing for the indoor gardener.  Sure, they provide the all-important light photons essential for photosynthesis – your plants ain’t growing without them!  But these same lamps also generate a lot of radiant heat!    If your plants grow too close to your lamps they will become too hot and shut down (stop photosynthesizing).  In extreme cases they will scorch and burn and the growth tips will die.  This causes untold stress to your plants and drastically reduces your yields.

On the other hand some growers are overly cautious and raise their grow lights too high, causing their plants to stretch in search of more lumens.  The ongoing aim of every indoor gardener is to get as many growth tips in the “sweet spot” as possible.  This is the area where your plants are just at a safe distance away from your bulbs and receiving maximum light intensity.

Different growers combat this problem in different ways.  All growers should try to move the air in between the tops of their plants and the lamp using an oscillating fan.  Some growers also air-cool or water-cool their grow lights while some put their lights on a mover or spinner.

As well as a light meter, use a thermometer with a remote temperature probe to measure the heat at the tops of your plants.  For many popular indoor crops, the magic number is 82°F (28°C).  What’s the temperature reading at the top of your plants?

3.) Brrrrr!  Using Cold Tap Water!

First off, tap water can contain chlorine and chloramines plus high levels of other minerals (often not in a form that is useful to your plants) and other impurities.  You should always feed your plants with the best quality water you can.  Many professional growers and keen hobbyists take control over their water quality by investing in a water softener and reverse-osmosis water purifier.  Also, you should always make sure that the temperature of your nutrient solution is around 65 – 68°F (18 – 20°C) before feeding it to your plants.  Cold water shocks your plants’ roots and warm water contains drastically lower levels of dissolved oxygen.  If your indoor garden is suffering from high temperatures, using a slightly cooler nutrient solution can help your plants get through until you manage to correct your environment.

4.) Lights++ Environment–

So, you’ve managed to dial in your indoor growing environment with two, three or four lights and you’re growing healthy, happy plants and enjoying regular crops of your favorite veggies all year round.  Great, but don’t make the mistake of thinking you can expand by simply adding more lights!   You need to also consider how this will effect your growing environment.  Firstly, more plants will mean more transpiration, and a need for more CO2.  More lights equals more heat to get rid of.  So if you are thinking of adding more grow lights, make sure you budget for increased air transfer too – you’ll definitely need it!

5.) Unruly Plants

A crucial skill that every indoor gardener needs to learn is how to shape and train their plants so that they make the most of any artificial light source.  You need to let your plants know who’s boss.  Do not grow your plants too large.  Small to medium sized specimens are the way forward for most indoor growers.  Remember, your plants receive exponentially less light the further they are from the lamp.  As most gardeners light their plants from above, a common goal for many indoor growers is for shorter, squatter plants with wide canopies.  Think of a candelabra.  Pruning out the leading growth tip will encourage many types of plants to adopt this formation.

TIP:  If you are growing plants that are sensitive to photoperiod bear in mind that they will not respond immediately when you change your light cycle to induce flowering.  Growers of many plant varieties are often stunned by the amount their plants bolt (or stretch) after changing the day length simulated by their grow lights.  Err on the side of ‘small’ when deciding when to switch your plants from vegetative to flowering mode!

6.) Grow Like A Gardener, Not a Robot

So you think you’ve got your nutrient recipe down and now it’s just a question of making it happen.  But the best growers are always in a state of flux.  They are observing their plants on a daily basis, getting in among them, looking for signs of under / over fertilizing and adjusting their nutrient regimen accordingly.

This is especially important if you are making any chance, whatsoever, to your growing environment.  Improved air exchange or CO2 levels in your indoor garden will cause your plants to grow more vigorously.  The saavy grower observes and recognizes this and increases the strength of his nutrient solution accordingly.

Conversely, if the ambient temperature inside your indoor garden rises above optimum levels (e.g. during the summer months) your plants will inevitably use more water.  You should therefore decrease the strength of your nutrient solution.

7.) Stale Food

Re-circulating your nutrient solution?  Great – you’ll save on precious water resources, not to mention expensive nutrients and additives!  But ask yourself – how often do you really drain your reservoir, then rinse, and replenish with a fresh batch?  Once every week?  Once every two weeks?  Or once every … when you can be bothered?  Younger plants will tolerate less frequent nutrient solution changes than more mature plants.  But if you’re really going to turn on the charm, the time for super frequent nutrient solution changes is during flowering and fruiting.  This is when your plants’ nutrient requirements are at their highest and will benefit most from regular nutrient solution changes.

8.) Poor Propagation

Care early on pays massive dividends later.  Be especially patient and watchful during the propagation stage.  Give your plants time to establish healthy root systems before rushing them into a hydroponics system and flowering them off.  Ensure humidity levels are kept fairly high at 60-80%, especially early on.  This reduces stress on the young plant which, in turn, allows it to focus on that all-important root system.

A plant that has been “hardened off” for five or six days under a fluorescent veg lamp, for instance, still needs to be introduced to a 1000W metal halide with care.  Raise the metal halide 3-4 foot above the plants until you see the first signs of growth.  Break those babies in slowly.  What is often diagnosed as “transplant shock” is often more due to the shock of an increase in light intensity.

9.) Lack of Oxygen

Dissolved oxygen in your nutrient solution is so important we can’t harp on about it enough.  Oxygen in your nutrients promotes root health and speeds up your plants’ metabolism meaning it can grow faster and bloom copiously!  Lack of oxygen in your nutrients, on the other hand, invites all sorts of problems, the leader of the pack being pythium which can destroy your crop in a matter of days.  You can increase levels of dissolved oxygen in your nutrient solution by bubbling air into it – the smaller the bubbles, the better!

10.) Don’t Be a Dirty Sanchez

What’s that carpet still doing in your indoor garden?  Is that decomposing plant matter in the corner over there?  Still not got rid of that bag of old root balls from last crop?  Get a grip on your garden!  Clean as you go.  Keep it as spotless as possible.  Filter all air vents.  Think of your indoor garden as a laboratory and you won’t go far wrong.  The cleaner your growing environment, the fewer viruses your plants have to fight; the more energy your plants can put into their primary mission – growing and blooming!  Cleaning sounds boring, and it is.  But how boring is 10% more yield?  Nuff said.