The Rules of Growing

An Amazing Grow Room Built Inside of a Cave: Birds Botanicals

An amazing grow room built inside of a cave: Birds Botanicals

Most of us live a technology-packed, fast-paced life with push notifications influencing our behavior as we walk down the street, and our pockets constantly buzzing, dinging, and ringing as we sync our ever-busier schedules from phone to tablet to desktop. It is no surprise that we have lost touch with Mother Nature. Whatever the excuse for our lack of connection with the earth, the fact remains that sometimes what we need most is our hands in the dirt as a reminder that all of our scientific innovations and accomplishments still pale in comparison to the magic of a seed sprouting and growing into the very food that sustains our bodies. Gardening is for everyone. It is a reconnection with nature, a time where we can think in peace, pound our frustrations into the soil, and all the while regain a Zen state of being. No matter your schedule or living situation there is a type of garden that will fit your life!

Traditional Gardening:

The Backyard Garden – Simple and easy. Find a sunny spot in your yard and dig away. Any size plot will do, just stick your shovel in the ground and start turning the soil. Add plants or seeds and you have a garden!

The Raised Bed GardenFor the DIYer or those of us that have less than ideal soil, simply buy or build a raised bed, fill it with soil, and start your seeds.

The Square Foot GardenFor the space challenged, the urban gardener, or the balcony bound, a container or a few 3-5 gallon pots of soil along with a little planning and some organic seeds, and you are on your way to food self-sufficiency.

Urban / Modern Gardening:

 The Closet Garden – For anyone with a closet to spare. Protect the floor, reflect the light  (more on that in a minute), add a grow light, soil, and some seeds, and you can be a year round farmer.

A Great Example of a Grow Room: See Why Below...

A great example of a grow room

 The Grow Tent GardenThe simplest and fastest way to have a garden that meets your needs, as well as the needs of your plants. A perfect fit for every space (they come in lots of sizes), with all of the forethought already built in, it will make your garden a lush cornucopia in no time.

The Vivarium – This terrarium-style garden can be designed to meet the needs of more exotic plants, but for you “Type A” control freaks out there this might be what you are looking for. These little gardens are designed to be tiny working ecosystems behind glass. Attractive and compact, it is a perfect fit for your high rise apartment overlooking the concrete jungle, adding a bit of nature back to your brick bastion. Check out Orchid Karma for an exciting look at Vivariums.

A Vivarium is Like a Living Painting in Your Home

A Vivarium is like a living painting in your home

The “Out of the Box” Garden:

The Trailer Garden – Although not every gardener’s cup of tea, this type of garden is proving to be perfect for dooms day preppers and businessmen alike. It’s essentially a re-purposed  shipping container transformed into a cash cow or an end of the world Eden. Check out our friends at Podponics in Georgia for a more in-depth exploration of this contemporary take on farming.

A Shipping Container Makes a Great Garden...

An impressive garden built inside of a shipping container

The Cave Garden – I admit this one is a bit of a stretch as most of us do not have a vacant cave in our real estate portfolio, but this is really cool. What can you do when your mine shuts down, and you are left with a maze of tunnels winding inside the earth? Well if you are smart you may turn it into an underground farm. Check out Bird’s Botanicals to see how this gardener made an environment without sunlight into a horticultural oasis.

The Rooftop Garden – With a strong movement towards locally grown produce and a desire to reduce carbon footprint, many gardeners have transformed urban rooftops into productive and profitable farms.

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So what do these different gardens have in common? Basic needs. All plants require that five basic needs be met: Light, Air, Water, Fertilizer, and Substrate. Let’s examine how these needs are met by growers using the the various gardening methods above.

A Rose Grower Has Chosen To Use High Pressure Sodium Light to Grow Their Roses Indoors

A rose grower has chosen to use high pressure sodium light to grow his roses indoors.

Light:

Light provides the input of energy for the chemical process of photosynthesis that turns carbon dioxide and water into sugar and oxygen. Outdoor gardeners simply utilize the sun as their light source; after all it is free and effective on all but the cloudiest of days. Indoor growers like the closet gardener may employ a variety of light sources to provide energy to their gardens including fluorescent, HID, LED, and plasma lights. All mentioned will work for providing the energy necessary for photosynthesis, but some might be better suited to your needs. Talk to the associate at your garden specialty or local hydroponic store to find the best light for you.

Air:

Air is a category that encompasses several factors including carbon dioxide, temperature, and humidity. All of these are critical to plant growth and are all important to account for in any type of garden.

Carbon dioxide naturally occurs in the air we breathe (and ironically by the air we exhale), but the 400+ parts per million (PPM) in the air may not be sufficient if there is not enough air exchange or air movement in the garden. Outdoor gardeners have it pretty easy in that the natural movement of air ensures they always have enough CO2.

Indoor growers who have constructed rooms and grow tent gardeners must actively work to ensure their plants receive adequate CO2. For a grower just starting out a grow tent can be a good option. The grow tent manufacturers built in all of the same universal and necessary features of a grow room, affording a novice grower a well designed grow space without the years of experience necessary to design a grow room on their own.

A Well Designed Grow Room: Grow Tents offer all of the Same Features with Less Work

A well-designed grow room: grow tents offer all of the same features with less work.

One of the best things about grow tents are that the manufacturers, knowing that CO2 is necessary, have designed ventilation holes for both the intake and exhaust of air. Exhausting the air with an inline fan creates negative pressure inside the tent, and allows for the passive (or active if a second fan is also used) flow of fresh CO2 rich air from outside via the intake flaps. A gardener can also choose to supercharge their indoor garden by utilizing either bottled CO2 or a COgenerator to increase the available amount of CO2 in the room to 1500 PPM, but we’ll touch more on methods of adding CO2 to grow rooms in another blog post.

Achieving the Proper Temperature Inside The Cave Garden Took 6 Months: Now it is Perfectly Controlled With Just the Heat From the Lights & a Network of Fans

Achieving the proper temperature inside the cave garden took 6 months. Now it is perfectly controlled with just the heat from the lights and a network of fans.

Temperature requirements vary with the plant, and although most plants can survive for a short time outside of their ideal temperature range, longer exposure to extreme temperatures will slow growth and possibly kill them. Some orchids for example, like the Phalaenopsis (2nd most grown potted plant in the world) prefer a minimum of 65°F but prolonged exposure to temperatures below 50°F will cause severe damage or even death. That is why I must tip my hat to the ingenuity of David Bird, the cave gardener. He knew the ambient temperature of the cave in the mid 50s combined with HID lights would increase the temperature by 15+ degrees providing ideal temperatures for his tropical plants. Cooling is accomplished with fans pulling colder air from unheated areas deeper inside of the cave, while simultaneously exhausting the warm grow room air.

Humidity is sometimes overlooked by gardeners, but a necessary factor to be aware of and mitigate. Plants will grow in a wide range of humidity but some are more finicky than others. Humidity being too high can result in an environment that is overly hospitable to mold and bacterial infection, while low levels of humidity can stress a plant as it tries to replace moisture constantly lost to transpiration. The vivarium gardener must keep a watchful eye on their humidity as the small volume of air in the garden allows for rapid swings in humidity with slight increases in temperature. Often both a humidifier (to raise the humidity) and an exhaust fan (to lower humidity) are built into the design of a vivarium.

Water:

Water is necessary for all life, and one that all of our gardeners must supply. Fresh water can be provided from any number of sources including streams, reservoirs, ponds, aquifers, and wells. One of the simplest and best sources of water is rainwater. Using a simple rain water collection system and a rain barrel allows our rooftop gardener or square foot gardener to provide fresh water to their garden. When it comes to water, the question isn’t just its source, but how to use it. For plants growing in either soil or soilless mix, the best advice comes from a sage old orchid grower who said, “You can never water too much, only too often.” What he meant by that is if you water a little bit every day the growing medium will stay wet and the roots will rot. Conversely if you water a 1 gallon pot with 20 gallons of water the growing medium will be fully saturated but as long as you wait until the growing medium dries out appropriately your plant will not suffer. In fact heavy watering will help prevent fertilizer build-up in your growing media.

This Roof Top Herb Garden Relies on Rain Water for Irrigation

This rooftop herb garden relies on rainwater for irrigation

Fertilizer:

There are 16 elements that plants must have, although some would place that number in the twenties. There are many brands and formulations of fertilizer to choose from, and none of them are “the best.” That is because different plants, growing mediums, and growing environments all necessitate different fertilizer choices. So what do our square foot and back yard gardeners do? Many make their own fertilizer using grass clippings, leaves, and organic kitchen waste, by tossing it into the compost bin. It takes just a few months for free, supercharged, rich compost for their gardens that feeds the plants an organic diet rich in minerals and nutrients, while improving the quality of their soil.

Square Foot Raised Bed Garden

In a square foot garden, using rich organic compost helps improve the soil

Substrate:

The growing medium can have a significant impact on the success of any garden by determining several factors: moisture, pH, drainage, fertilizer retention (CEC), and oxygen content in the root-zone. There are many growing mediums to choose from: soil, soilless, LECA stone, diatomite, perlite, vermiculite, coconut, redwood fiber, sawdust, recycled glass (Growstone), volcanic rock, gravel, rockwool, and even air. Each of the growing mediums listed above (and by no means is it an exhaustive list) have attributes and differences that will make them more or less effective in a particular application. However, sometimes you just do not have many options, like the two inventive youths from Swaziland who took the limited materials they has access to (sawdust and chicken manure) and used them as the media for a hydroponic science experiment, winning $50,000 and the Scientific American’s inaugural Science in Action award.

Regardless of the type of gardener you are, the style of gardening you practice, or the crops you grow, the five basic needs of plants will always need to be addressed. The better you are at meeting the fundamental needs of your plants, the greater amount of attention you can devote to the details which differentiate a good gardener from a great one. With so many gardeners and innovative methods of farming coming into practice, remember the basics of growing remain the same.

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The Kratky Hydroponic Method: A Simple & Effective Hydroponic Technique

When I first heard about this new method of growing from a friend, I thought he said it was called the “Cracky” method. After hearing his explanation of how it worked, I thought my friend was actually on CRACK! I was more than skeptical- I was incredulous. After some research my curiosity got the better of me, and I decided to try this “revolutionary” new method of hydroponic growing. The style of growing was developed by B.A. Kratky at the University of Hawaii. His method contradicts traditional hydroponic theory on multiple levels: no active movement of water, no aeration of the reservoir, no change-out of nutrient solution. It is best for growing leafy greens, such as the lettuce shown here, and it has not been proven suitable for growing fruiting or flowering crops. All I can tell you is that although contradictory to my years of education and training, I cannot argue with the results in front of me…

Kratky Hydroponic System 1 Week After Planting

Kratky Hydroponic System 1 Week After Planting

Kratky Hydroponic System 2 Weeks After Planting

Kratky Hydroponic System 2 Weeks After Planting

Kratky Hydroponic System 3 Weeks After Planting

Kratky Hydroponic System 3 Weeks After Planting

Kratky Hydroponic System 4 Weeks After Planting

Kratky Hydroponic System 4 Weeks After Planting

Kratky Hydroponic System 5 Weeks After Planting

Kratky Hydroponic System 5 Weeks After Planting Ready to EAT!

The basic idea behind the Kratky method, as it has been dubbed, is that the plants start with their roots submerged in a mixture of water and fertilizer as seedlings. The growing container should be well sealed to minimize moisture lost to evaporation. The roots will then grow longer into the water as the water/fertilizer mixture is absorbed by the plants. As the water level goes down, the plant will make aerial roots able to absorb the necessary oxygen from the airspace between the top of the water and the top of the container. By the time the water is gone, you should have harvested your lettuce and can start again. No pH adjusting, no adding more fertilizer, no topping off the water/fertilizer mixture. I admit I am shocked, but I swear it works. Grow some in a Kratky Method Hydroponic System and see for yourself.

An Element Too Good To Pass Up: The Benefits of Silicon to Your Garden

Si on Periodic table

Si on Periodic table

Would you use a product that would increase your harvest weight by as much as eighty percent? What if it also provided increased tolerance to environmental stressors such as drought and high temperatures, provided resistance to insect attacks, and additionally had been proven to protect your crop from powdery mildew (Sphaerotheca fulginea), root rot (Fusarium oxysporum), damping off (Pythium), and grey mold (botrytis cinerea)? Now, what if I told you this product is real, that it is available, and that the above list of accolades does not even scratch the surface of what it has been proven to do?

This miracle product happens to be the second most abundant element on the surface of the earth: silicon. Although not regarded as one of the 16 essential nutrients that plants must have to grow, silicon may prove to be the best addition to your fertilizer regimen you can make. Plants have certainly been shown to grow in hydroponic solution devoid of silicon, but when the same plants are grown with silicon, tissue analysis has shown that silicon accounts for as much as 10% of the dry weight of the plant. Everyone wants bigger harvests, and using silicon could be the key. A study conducted by the University of Florida found that silicon responsive plants had “dry weight increases (which)…ranged from 6-80% depending on the species” (Chen et al, 2000).

So how does this “non-essential” element have such a huge impact on so many facets of your plants’ existence? Silicon performs its multitude of functions in two ways: by the polymerization of silicic acid leading to the formation of solid amorphous, hydrated silica, and by being instrumental in the formation of organic defense compounds (Epstein, 2009). To simplify, silicon is actively transported into the plant similarly to macro nutrients like potassium. From there it moves up the xylem and is distributed out to the growing shoots. There, the silicon forms larger polymer chains (polymerization) which allows plants to deposit silicon in the form of solid amorphous (non crystalline), hydrated silica which is then incorporated into the plant’s cell walls, thereby armoring the plant’s cells against rasping and sucking insects. If you are growing leafy greens think how much better the texture of the leaves will be when every one of the millions of plant cells has thicker cell walls from the added silicon.

Additionally, silicon is deposited in the trichomes of plants, according to Epstein; it “is the silica in trichomes that lends leaves and awns (stiff bristle or hair-like appendages in plants) the roughness and the toughness that impede the penetration of herbivores and pathogens through the cell walls. It acts as a physical barrier.”

The other mode by which silicon benefits your plants is in its ability to promote the synthesis of organic defense compounds. When a plant is under attack by insects or pathogens it sends out chemical messages which trigger the plant’s natural defenses. A study conducted on cucumbers yielded conclusive proof the plants were protected from fungal pathogens by the presence of silicon in the hydroponic solution (Cherif et al, 1992).

Another benefit of the use of silicon is that it balances the nutrient absorption of your plants. Silicon can balance nutrient elements in plant tissue through the suppression of Al, Mn, and Na, and by mediating the uptake of other elements like P, Mg, K, Fe, Cu, and Zn (Chen et al, 2000). When used with peat or bark based soil/soilless mixes, silicon prevents the over-acidification of the mix, which can lead to pH induced nutrient lockout, as well as inhibiting the absorption of toxic elements like aluminum. When anthuriums were grown in soil with available aluminum the tissue tested had 150 PPM of aluminum, while the plants grown in the same soil but fed silicon tested at only 41 PPM.

One bit of advice when introducing silicon additives into your feeding program: silicon products must be the first thing added to a fresh reservoir of water, even before base nutrients. By their inherent chemical properties silicon additives are alkali, and because most fertilizers are acidic they must be diluted before they are added to a hydroponic reservoir or any water fertilizer mixture. This will allow for the concentrated alkali silicon solution to diffuse, thus preventing localized chemical reactions from causing the formation of undesirable nutrient precipitates.

Silicon can be a cure, a booster, a medicine, and a messenger. It can counteract damage to your plants from extreme temperatures or prevent the absorption of toxins that would otherwise destroy your plants. It can send insects to more inviting hosts, and it can increase the weight of your harvest. Silicon truly is a multipurpose beneficial element that should be in every gardener’s toolbox. Think of it as the best and cheapest plant insurance you can buy!

Control Your Plants by Controlling Your DIF: A Guide to Daytime and Nighttime Temperature Differential

Day Night Temp Differential

We have all had that friend that needs to control everything; from where you eat, to what movie you see…everything seems to be their choice. While that friend might need to loosen up (or maybe they need to seek professional medical attention), controlling all aspects of your garden will repay you in spades. Indoor gardening is all about control; control over photoperiod, control over temperature, control over plant nutrition, etc. By controlling everything from the photoperiod to the specific nutrition a plant receives, we effectively remove all barriers that may hinder our plants; optimally that control will allow them to reach their maximum genetic potential. An often overlooked environmental factor that can greatly impact your plants is the DIF, or the day night differential. DIF is the difference in the highest day time (lights on) temperature and the lowest night time (lights off) temperature. Control over your DIF will give you control over your plant’s height and internodal spacing without the use of dangerous or untested chemicals or plant growth regulators.

Research about DIF is not new to science; back in 1944, Went made detailed observations about the effect of the night time temperature (Tn) on the stem growth rates of tomato plants. He originally proposed the term ‘thermoperiodicity’ to describe the apparently greater rate of plant growth and development in diurnally fluctuating temperatures compared to plants grown at constant temperatures. Although his research was disproven in 1990 by Ellis et al, Went’s research was the beginning of our attempts to understand the impact of temperature on plant growth.

In 1983 while studying the effects of temperature on the Easter Lily (Lilium longiflorum), it was observed that there was an interaction between day and night temperatures that affected the length of the floral stem. This relationship, coined DIF (Erwin et al, 1989), was used to describe the elongation of the stem in response to diurnal thermoperiod and photoperiod interaction. They noted that the magnitude and nature of the internodal elongation varied between different species and also between different cultivars of the same species.

Plant height or stem length is simply the sum of the lengths of each of the internodes. Therefore, to control plant height one must manage internode number, internode length, or both. The number of nodes and the length of each internode (the distance from one node to the next) are strongly influenced by temperature. As DIF increases, so does the internode length of most plants. It is important to understand that the effect of DIF on internode length is due to increased cell elongation, and not an increased number of individual plant cells. Plants respond rapidly to changes in DIF, with altered growth rates that are often observable in as little as 24 hours.

Although managing your garden’s DIF will afford you some control over your plant’s internodal elongation, there are factors that influence or compound the DIF response. The Average daily temperature influences internode length and thus the response to DIF in many plants. The quality of the light being received by your plants has been shown to influence the DIF response, presumably through effects related to phytochrome photoequalibria (Moe and Heins, 1990). While incandescent lighting used for photoperiod control can eliminate a plant’s response to DIF, fluorescent lighting has been shown to increase the response (Moe et al, 1991).

With the proven effects of DIF at controlling plant height, how do you exploit this information to grow a better garden? First, day time and night time temperatures must be controlled independently and excess humidity must be removed from the air by using dehumidifiers. Watch for significant increases in your DIF; a large swing between your day time and night time temperature will bring a marked increase in humidity. If the high night time humidity level is left unchecked it can lead to mold and disease on your fruits and flowers.

During the vegetative light cycle (18 on, 6 off), your target DIF should be 5 degrees Fahrenheit. Try to maintain a daytime or “lights on” temperature of 85 degrees Fahrenheit, and 80 degrees Fahrenheit when the lights are off. For the blooming or fruiting phase of your plant’s life cycle (12 on, 12 off), your target DIF should still be 5 degrees Fahrenheit; but the daytime “lights on” maximum temperature should be limited to 80 degrees Fahrenheit, and your “lights off” temperature to 75 degrees Fahrenheit. By maintaining the DIF at 5 degrees your plants will exhibit the tightest internodal growth, lowering the overall size of your plants while building a tight network of branches. Remember that the temperature and DIF recommendations above are starting points as different species and cultivars (or clones) will react differently to a controlled DIF. Controlling your DIF could make all the difference to your garden!

And the Winner is…

Heavy 16 & APTUS  vs GH Duo

Which Fertilizers Will Work Better? Check Back Soon and You Decide…

In one of our recent blogs, Atlantis Hydroponics let the world decide which fertilizer experiment we would conduct, blogging the results in real time as they occur. The winner of the experiment poll from the blog Which Hydroponic Fertilizer is Best? Experiments with a Purpose! is:

Heavy 16 and Aptus versus General Hydroponics Flora Duo, garnering 41.82% of the vote!  We will be setting up a side by side trial garden to compare how these fertilizers and additives perform. We are very excited to test Heavy 16 and Aptus as they are two brands that we currently do not stock; as a policy, Atlantis Hydroponics only carries fertilizers and additives that measure up to our high standards of quality after in-house testing by our hydroponic research and development team. Check the Atlantis Hydroponics Blog frequently for pictures and updates of the experiment.

Is there a Light at the End of the Tunnel? A Look at LED Technology in Horticulture

LED Side by Side Trial With Lumi Grow ES330

Side by Side Trial – Lumi Grow ES330 LED vs. 270 Watt HPS (on left)

We have all seen the plethora of advertisements in the magazines about LED grow lights.  When LEDs first hit the horticulture market they were little more than Light-Brite™ toys with expensive price tags and big promises. They claimed that each watt of LED lighting was equivalent to more than 10 watts of HID lighting, on top of which they asserted LEDs would produce no heat, have better penetration of light through the canopy, and that they would revolutionize the growing industry.  Unfortunately, the early LEDs were unable to deliver on most of their promises.

LED stands for Light Emitting Diode.  Unlike traditional light sources with delicate filaments, electrodes, or pressurized gas filled lamps (i.e. HIDs), LEDs are solid state electronics, and as such are more robust and longer lasting (Bourget, 2008).  Solid state by its most simple definition means “made without any moving parts.”  A flash memory card is solid state device, where as a typical hard drive is not.  By not incorporating moving parts into the design, solid state electronics are less likely to break, wear out, or malfunction. This added level of reliability is one of the biggest benefits of LEDs.  Current LEDs are rated for as many as 70,000 hours of operation before they reach the point where replacement is advisable.  Although they will still be working at that point, at 70,000 hours of operation they will have reached a 30% diminishment in luminous output making it cost effective to replace them.  Seventy-thousand hours means that a grower using LEDs will not change the diodes for almost 16 straight years, running 12 hours per day, every day.

LEDs have not always had the longevity and reliability they are able to deliver today.  The history LEDs being used in horticultural applications started in the late 1980’s with crude arrays of red only (660 nanometer) LEDs.  Early experimentation with LEDs in horticulture was driven by their potential for use in growing food for space travel.  In the late 1990s the crops research group at the Kennedy Space Center conducted several studies on the yield and physiological response of several crops to LED lighting.  LEDs became even more promising with two critical advances in LED technology; the advent of blue LEDs, and high output diodes.  For a full timeline of LED lighting in horticulture please see the timeline below (HortScience Vol.43(7) Dec. 2008)

Horticulture LEd Lighting Timeline

Horticulture LEd Lighting Timeline

The advances in LED technology keep on coming; each decade LED prices have fallen by a factor of 10, while their performance has grown by a factor of 20 (a phenomenon known as Haitz’ Law).  So it seems the future of LEDs is getting brighter! In the next blog we will look at the different applications of using LEDs for growing plants and see if they are close to delivering on their original promise of revolutionizing the horticultural world.

Bringing Your Outdoor Garden in for the Winter: Don’t Leave Your Plants Out in the Cold!

Snow on Garden

Snow on Garden

The leaves are changing; the temperatures are steadily dropping day by day. It is time to tend your garden one last time before Jack Frost’s impending visit. Cover your garden beds with several inches of chopped shredded leaves to protect tender plants and bulbs. In September a high nitrogen fertilizer applied to your lawn would have promoted vigorous new blade growth, but now in November it is more beneficial to use a high phosphorous fertilizer which will add inches to your lawn’s roots. What do you do with those container plantings, citrus trees, and expensive ornamentals that are planted in pots on the patio or porch?

Simple; you build a small indoor garden to overwinter your tender tropicals and pricey petunias. It can be fun and easy to bring plants inside and can also allow a real jump on planting next year’s garden. Setting up an indoor garden requires a few simple steps. First look at the plants you want to bring inside, also take into consideration if you want to start annuals for next year’s garden, or if you would like to grow some fruits or vegetables for yourself or your family over the winter. Now that you have a rough idea of how much space you will need for your garden, look around your home for an area that can accommodate it. You will need to find a space which will be protected from the cold, has electrical access, and preferably is close to a sink and drain. I suggest you consider a closet that doesn’t get much use. It will allow your garden to be tucked away out of sight, when you so desire.

If you choose a closet line the walls with plastic sheeting like Panda film to create a moisture barrier. Put a tarp down on the floor and use a staple gun to tack it 6” up the side of the walls. This will protect your floor should you inadvertently spill a bit of water. If all this sounds like too much trouble then simply purchase an inexpensive grow tent. A grow tent also offers the advantage of being able to be placed inside any existing room while maintaining a closed environment for your garden.

Next you need a light. Based on the size of your garden, and your financial and electrical constraints choose the lighting for your particular situation. The most common lights for over-winter gardens and those new to indoor gardening are either a 400 watt High Pressure Sodium / Metal Halide light system or T5 fluorescent fixtures that will fit your space. A 400 watt HPS light can easily cover a 4’ x 4’ garden. By including some shelves off to the side you can make even better use of your space. If all you want to do is keep plants alive over the winter then a 400 watt light is capable of covering a 6’ x 6’ space. Be aware that a 400 watt light gives off about 2,000 BTU of heat per hour, and you should plan to use this heat to warm your garden or help heat your home. Also make sure your plants are at least 18” from the bulb to avoid burning the tops of your plants.

Once you’ve hung your light and protected the walls and floor it is time to move your plants inside. In the interest of keeping your plants healthy it will be necessary to treat your plants with an organic insecticide to prevent bringing pests into your new indoor oasis. Wipe down planters and pots with a wet rag to remove any dirt. Now you are ready to bring your plants in to their new winter home.

Lumens are for Humans but PAR is for Plants!

Prism Splitting Light

Prism Splitting Light

It blew my ten-year-old mind when my “all knowing” grandmother told me that the Blue Jay we were watching was in fact not blue. She explained that light is composed of many colors, and it is the colors that are reflected, not absorbed that our eyes perceive as the color of an object. This is a necessary reminder that what is perceived might not be what it appears to be. For decades the indoor gardening community has used Lumens as the standard increment for the measurement of light. Lumens were unfortunately a poor choice, here’s why.

Diagram of How a Prism Works

Diagram of How a Prism Works
coutesey of freedigitalphotos.net

Lumens are essentially a measure of brightness based on human perception. Precisely, a lumen is equal to the light emitted by one candle falling on one square foot of surface located one foot away. This however presumes a human as the perceiver of the light. Plants “perceive” light differently; from a plant’s perspective, light that is useful for photosynthesis is not necessarily bright. Light, or more specifically, visible light is made up of wavelengths of energy on the electromagnetic spectrum ranging from 380-770 nm (nanometers). Plants utilize wavelengths from 400-700nm for photosynthesis. Brightness does not accurately describe if the light will be more or less useful to a plant.

Light can be characterized in other ways when discussing its benefit to plants. Color temperature is often referred to in the horticultural industry on lamp boxes to describe the color of the light emitted by the lamp. Does 4,000K grow a plant better than 7,500K? Color temperature is listed in Kelvin (K), which is a measurement of temperature. The temperature of what you might ask? It is a description of the relative whiteness of a piece of tungsten steel when heated to that particular temperature in degrees Kelvin. This accurately characterizes the color of the light as we perceive it, but color temperature again fails to address how effective a particular light source will be at providing the energy necessary to drive photosynthesis.

Don’t get frustrated by this inadequate information. There is in fact a measurement that precisely describes how effective a particular light will be for growing plants; PAR (Photosynthetic Active Radiation). PAR spectrum accounts only for light or more precisely photons emitted between 400-700nm. Scientists have concluded that it requires about 9 photons to bind one CO2 molecule in photosynthesis [6CO2 + 6H2O (+ light energy) C6H12O6 + 6O2]. Even though blue photons have more energy it has also been found that there is little difference between the effectiveness of red versus blue photons at driving photosynthesis as long as the photons are within the 400-700nm range. This leads to a direct correlation between the number of photons produced in the PAR spectrum by a given light, and the photosynthetic potential of that light.

Photons are emitted by light sources in very large numbers so we do not talk about billions or quadrillions of photons, instead we refer to them using the multiplier moles (which stand for 6.0221415 x 1023) To make the numbers even more accessible, the number of moles is often divided by 1 million resulting in micro-moles (μmol). Light sources emit photons continuously over time so the number of micro-moles is more accurately described as μmol/per unit of time (most commonly seconds).

When trying to quantify how effective a light source is beyond the total output of μmol/per second, you must consider one last piece of information… the size or area of your garden. Inevitably some of the photons produced will not reach your garden. So the most accurate representation of a light source’s ability to drive photosynthesis will take into account the area being lit and how many photons reach that given area per second; usually a square meters. That representation which actually summates the effectiveness of a light source for photosynthesis is written as μmol/m2/s. This descriptor is actually referred to as Photosynthetic Photon Flux Density or PPFD for short.

So in light of all of the information above, let’s remember that lumens are not a useful descriptor of a light’s ability to drive photosynthesis. I think I will sit back with a drink, and digest all of the information about PAR & PPFD while I watch the not blue Blue Jay outside my window.

Key to Success- Keeping a Clean Hydroponic System

Clean Hydroponic System

Want to grow happy, healthy plants every time? Well here’s a tip that could help you keep your garden on a nonstop path to success. The hydroponic system your plants live in will run more smoothly and efficiently with a little attention to detail. Plants are living organisms, and they attract many other forms of life to your garden. The photo above shows what your plant nutrients will grow in addition to your plants. Algae is generally harmless, but allow it to grow out of control and you might end up with a big mess on your hands.  Not only does it produce a terrible grow room odor, algae can harbor pathogens and even consume valuable nutrients before your garden plants (what a waste of fertilizer)!

It takes only a few minutes and some elbow grease to make your hydroponic system look as good as the day you bought it. Routine cleaning will ensure that no mess is too much to handle! And did you know that your equipment will last longer if you scrub it from time to time?

My favorite things in life do not include scrubbing hydroponic flood tables, but routine cleaning beats having to buy new equipment. This holds true for all types of hydro systems as well as water pumps. Deep Water Culture buckets, for example, will perform better and your plants will be healthier if you scrub them lightly with warm water between each nutrient change, rather than simply pouring out and replacing water. Cleaning can also help you avoid pH spikes and root rot.

Clean Hydroponic System

Keeping your indoor garden tidy is just like going outside to a raised bed garden and pulling weeds, it has to be done.  If we don’t weed our gardens or clean our tables then the stuff we don’t want to grow will take over and cause all of our valuable time, energy, and garden plants to go to waste.  And who wants to watch their garden die?

Well maintained gardens will thrive and in return reward their gardeners for a job well done. Clean equipment not only looks good, it helps to keep disease pathogens and pests in check. So if you’re really in it to win it, remember that cleaning is a small price to pay for the happiness of your garden, and happy gardens make happy growers!

Indoor Garden Lighting (Part 2): Choices, Choices, Choices!

Sun and Fluorescent bulb

Photo courtesy of Freedigitalphotos.net

In my prior blog I discussed the obstacles that indoor gardeners must contend with when using horticultural lighting as the primary source of light for their gardens. With those challenges of indoor garden lighting in mind, lets review what options indoor gardeners have when selecting lighting.

Fluorescent lighting comes in a variety of sizes, shapes, wattages and styles. The old standard 4’ shop light T12 bulbs (40 watt) produce about 2,600 Lumens. The newer 4’ T8 bulbs (40 watts) produce about 3,200 lumens. The preferred horticultural fluorescent lamps are T5 bulbs (54 watt) and produce about 5,000 lumens per 4’ bulb. There are also compact fluorescent lamps (or CFL) that have built-in ballasts in either 125, 200, or 250 watt options that produce about 45 lumens per watt.

Lamp Type 4’ T12 4’ T8 4’ T5 Compact Fluorescent
Lumens Per Watt 65 80 92.6 Roughly  45

The pros of fluorescent lighting are that they have relatively low wattage, can be utilized in all sorts of size areas and configurations, and they are more affordable than some of the other options. However, fluorescent lighting does not deliver the intensity of light to provide good penetration through the canopy. There are also issues with  fluorescents lacking the intensity necessary to produce fruit on high light plants. Lastly fluorecent lights give off a good bit of heat. They are an excellent choice for mother plants, clones, and young seedlings.

HID or high intensity discharge lighting has been the standard lighting for horticulture for decades. Although they produce an enormous amount of heat, they are able to provide good penetration of light through the canopy to about 3 feet. Utilizing switchable ballasts & different bulbs you can choose a spectrum heavy in blue light (Metal Halide) for vegetative growth, or heavier in red light (High Pressure Sodium) for flowering and fruiting.  HID lights are reasonably priced, they are proven as a primary or sole light source, and they able to produce enough intensity of light to allow high light plants to produce excellent crops. For more information about HID lighting, check out this helpful HID lighting guide.

Plasma Lights are a type of electrodeless lamp energized by radio frequency or microwaves. The interest in this type of lighting is driven by two factors: spectrum and the potential for financial savings (based on lower electrical consumption). The spectral output of a plasma light is almost identical to the light spectrum of the sun making it ideal for horticultural applications. Plasma lights are also capable of producing large amounts of light from relatively small amounts of electricity yet they still produce large amounts of heat. Currently there are Plasma Grow Lights available for sale made by Gavita Lighting in Holland but they are still in their respective infancy.  Based on my personal testing I will say they hold a LOT of promise.

LEDs or Light Emitting Diodes are starting to draw a lot of attention, not just from indoor gardeners but also from the general public. There are LED bulbs to replace your standard incandescent household light bulbs, LED flashlights, and even LED wallpaper. Why this explosion of LEDs, and can we as gardeners benefit from LED Grow Lights? Stay tuned to future blogs to find out.