“Gardening is civil and social, but it wants the vigor and freedom of the forest and the outlaw.”
— Henry David Thoreau, American writer
One of the biggest mistakes greenhouse rookies make is leaving the greenhouse as it is once they have build the greenhouse and put the benches and pots in. They forget some of the most important parts of the greenhouse, and those are the things that are inside, which some consider frivolous add-ons. However, these can help make your greenhouse growing experience much more successful.
There are a wide variety of items which you can install in your greenhouse, from misting systems and humidistat to lighting meters and even music. Yes, that is right, music can help you and your garden, yet many greenhouse builders do not even think about it.
Sound
The greenhouse looks great. You are ready to garden, but something is missing. The greenhouse is just a big empty glass box unless you can add some atmosphere to it through music. Many people consider the use of music to help plants grow as nothing more than folk knowledge, but studies have been done to determine if music helps plants.
In 1973, Dorothy Retallack published, The Sound of Music and Plants. In the book, she detailed the work she did at the Colorado Women’s College in Denver using bio-chambers. She would put plants in these chambers and then play particular styles of music, noting the progress and changes in the plants over the course of the experiment.
In the first experiment she found that playing a constant tone for eight hours disturbed the plants to the point where they would die within two weeks. However, using the same tone for only three hours a day caused the second batch of plants to grow extremely healthy.
She followed this experiment with one using radios. In one chamber, she turned the radio to the local rock station; the second chamber had easy listening music. She played the music for three hours a day and found that the chamber with soothing, easy listening music, in it had the healthiest plants. After two weeks, the plants in the easy listening chamber were leaning towards the radio. In contrast, the plants that were subjected to music such as Jimi Hendrix and Led Zeppelin were very weak.
Music for Your Consideration
At this point, you may be wondering what music you should think about using in your greenhouse. First, you need to consider how to get the music to the plants. Depending on how much you want to spend, you can have a complete surround sound system that broadcasts equally to all corners of the greenhouse, or you can have a radio set up that plays music loud enough it can be heard anywhere in the greenhouse.
A good course of action is to determine what music you find relaxing and what music you find irritating when you are trying to calm yourself. Keep in mind the music you find relaxing may be different from the music you listen to on a regular basis. You can enjoy thrash metal, but you probably do not find it relaxing. The types of music to avoid include heavy metal, hard rock, most types of rock, and alternative music. Pop can be okay if it is soft, as is easy-listening music. However, by far the best music to use is classical music. Classical music is not only calming, but plants really seem to enjoy it.
In a study by composer Don Robertson, he played modern classical music to one group of plants, and 16th century classical music to another group of plants. Plants that listened to the older form of classical thrived, most likely because the music from the 16th century composer was far more soothing than the more modern classical music.
According to some research, low frequency sounds can activate enzymes in plants, while promoting DNA replication and increasing the fluidity of the cell membrane in plants. Frequencies between 125 and 250 Hz were found to stimulate a plant’s growth the most, while frequencies of 50 Hz, produced plants with less growth. Another study by the Tuscan winery Il Paradiso di Frassina, found that shoot growth and leaf area per vine was higher on vines that had classical music playing near them, versus vines that did not have any music at all. In this study, it was found that the volume does not produce any noticeable changes, but low volume is probably the best as it is more soothing than loud.
Shading
In hot summer months, shade will be important for your plants. It will give relief from the sun on very hot days, and keep your plants from becoming burned out. Shading is used extensively on greenhouses located in hot climates like India. When you choose shading for your greenhouse, there are several options available to you. One of the most effective options is to have curtains that you can open and close throughout the day to provide your plants with a bit of shading. These are an inexpensive, but they do require you to go out to your greenhouse every few hours to adjust the curtains so your plants do not sit in the shade too long.
Shade Nets are a fabric with lockstitch construction that defends against fraying, tearing, and sagging. The fabric will not fade, mold, or mildew. You can use it to cover your entire greenhouse or parts of it.
Photo courtesy of Juliana America, LLC.
Curtain system
Curtain systems will work on one of two systems: a gutter-to-gutter system and a truss-to-truss system. The gutter-to-gutter system involves the curtains being pulled flat across the width of the greenhouse at the height of the gutters. One benefit of this method is that the volume of greenhouse air below the curtain is minimized; therefore, less has to be heated. There is also less installation and maintenance with this method. However, if you have circulation fans or heaters that are above the gutter level, the curtain will block the heat or circulated air from reaching your plants. It is harder to mix and reheat air in this type of curtain system as well.
Truss-to-truss system
The truss-to-truss system involves the curtains moving across the distance between one truss and the next. One advantage of these is that when rolled up or in a bundle, truss-to-truss systems are more compact and minimize the unwanted shade created by the bundle. Installation is easy, and the curtains can be flat at the gutter height, which therefore minimizes the heated area. These types of curtains can follow the slope of the roof as well.
This is an example of a commercial greenhouse that utilizes a truss-to-truss curtain system. It uses curtains along the sides of the greenhouse.
Drive mechanism
If you want to go the extra mile with your curtains, you can get a drive mechanism installed. This is an electric motor and gear box that will extend and retract your curtains for you. A drive mechanism can save you the time and effort of having to go and move each curtain individually, or as a whole with a crank, which can be very tough to do if you have large and heavy curtains. The push-pull drive can be used to move a truss-to-truss system, while the cable-drum and cable-chain drives can be used for both types of curtain systems.
Screening Agents
For the gardener on a budget, a screen agent can be a great alternative to a shading system. Although, it is still a shading option, these agents provide an easy, perfected, and cost effective method for providing you with the shading your greenhouse requires without the hassle.
Temperzon whitewash
Another option is temperzon whitewash, which is a screening agent used on glass and poly houses. You can get this in liquid form and it will dull the light coming into the greenhouse, giving your plants enough light, without too much heat. On days where you want as much sunlight as possible coming into the greenhouse, like rainy days, the whitewash will become transparent when wet.
Decilight®
Decilight® is a calcium-based screening agent that will work on glass and plastic and is one of the best methods of shading you can use to get the optimal screening and maximum heat reduction. In dry conditions, it will produce a screening rate of 80 percent, and a screening rate of 60 percent in wet conditions. Many horticultural greenhouses that have large crops use this method because it is very effective and is perfect for sunny regions. In addition, because it is made up of starches and carbonate, it is not harmful to the environment.
Luxtech®
Luxutech® is a screening agent that is easy to remove if you want to get rid of it, becomes transparent when it rains, and is free of harmful chemicals. In addition, it is long-lasting, which means you will not have to keep replacing it on your greenhouse panels.
If you want to go for the low-tech solution, which is even better than curtains, you can take care about where you are going to put your greenhouse. As mentioned previously, if you build your greenhouse so that it gets partial shade during the day, you will be doing your plants several favors. Your plants get the cooling aspect of the shade, and a break from the sun, which can become very hot in a greenhouse. Look for trees that can give some shading, or even a building that will provide shading from the sun’s rays. By just using a bit of thought and using your creative ingenuity before you put your greenhouse plan into the ground, you can save yourself time and money instead of buying curtains or screen agents.
Misting Systems
One of the drawbacks of a greenhouse is that, because it protects plants from the elements, it keeps out some of the vital necessities your plant needs to survive, such as water. Therefore, you need to provide water for your plants. You can walk around with a hose but this will often lead to wasted water, which means wasted money for you. It also means there is a time commitment for you to go out every day, or at least every few days, to water the plants. Instead, what you could do is install misting systems, which will help your plants grow, save water, and save time for you.
A misting system is also a very effective way to control the humidity within your greenhouse, which is essential to the health of your plants. In a greenhouse, you want to have a humidity level of between 50 and 70 percent, for the best results in growing your plants.
If you do not have a misting system within your greenhouse, it can be very difficult for you to keep the humidity from fluctuating greatly with the temperature changes. If the humidity level drops quickly, the plants can suffer from extensive stress. One of the important things about misting systems is that the water droplets are small enough that they will hang in the air, helping the humidity. However, if the water droplets were to be larger, they would just fall, without helping the humidity level. Depending on how high-tech the system you install is, you can get some systems that will detect the humidity level and either increase or decrease the level of humidity through spraying. One great thing about a misting system is that you can have fertilizer added to the water supply, which will allow the misting system to spray fertilizer on your plants, allowing them to grow better.
The misting system essentially takes advantage of the natural ability of the plants to process water through their leaves and roots. This is probably the biggest advantage of the misting system, along with how it aids in maintaining optimum humidity. There are, however, some disadvantages to misting systems that you should be aware of. Overly damp surfaces in a greenhouse where mist pay pool can create pools of water where bacteria and mold will be formed, which can be harmful to plants. Gray mold, which can cause infection in plants, is one type of mold to be aware of. Mildew can also infect plants and reduce the quality of the vegetation that you get out of your greenhouse garden. Some high end misting system will keep too much water from being emitted, which will then save you from having to deal with mold and mildew.
Mist & Cool® is a do-it-yourself misting and cooling system that can be used with an automatic timer.
Photo courtesy of Juliana America, LLC.
If you are going to get a misting system, you need to consider the type of misting nozzle that you are going to use. The most common type is the brass misting nozzle, which is reliable and will last for many years. If you cannot afford brass, you can go with a ceramic misting nozzle. Some of these nozzles have a stainless steel coating, but most ceramic misting nozzles are made entirely of ceramic. When you get a ceramic misting nozzle, you should find one that creates droplets between 1 and 10 microns in size. The smaller the water droplets the system creates, the more water pressure is needed in your system. Ceramic misting nozzles wear less than other materials, and therefore are a long-lasting product.
One thing to consider, when you have a misting system that has small orifices for the mist, is that the systems can become clogged. Misting nozzles will have a filtration system that will catch the particles, filtering out anything down to 5 microns in size, with another filter system filtering out particles one micron in size. Over time the filters clog and you will have to clean them. However, that being said, typically misting nozzles are low maintenance, and you will not have to check the filters often.
If you do want to clean the misting system, you will need to remove the misting nozzles. When water is left to sit in the nozzle, it can create a deposit that affects the nozzles which can clog the nozzle. If you want to clean it, remove the nozzle from the line and place it in a vinegar solution that is weakened by water. You can buy mist nozzle cleaners if you do not want to use vinegar in the system. Follow these simple steps to clean out your mist nozzle:
1. Leave the nozzles sitting in the vinegar solution overnight, and then take the nozzles out of the solution the next morning.
2. Tap them lightly with a screwdriver to loosen up the nozzle deposits, swirl it around in the solution once more to get any bits of particles still left in the nozzle.
3. Do not use pins or nails to clean out the holes in the misting nozzle because you can damage the nozzle and effectively keep it from working properly.
Grow Lights
It may seem odd to have lights in a greenhouse, because a greenhouse is designed to get the maximum amount of sunlight, but grow lights can be very beneficial in the offseason. During the winter, especially in northern latitudes, there is far less sunlight so you may have to supplement the sunlight with grow lights. In the winter, you may only get three hours of good sunlight for your greenhouse, and the grow light will help you get the extra amount of light that you need. A grow light is essentially an electric light, or a series of lights, that emit an electromagnetic spectrum of light that is beneficial to photosynthesis. These lights emit the same type of light spectrum as you would see from the sun, which allows for indoor growth in a home, and even in a greenhouse.
Incandescent grow lights
Incandescent grow lights use a red-yellow tone and low color temperature, but they are not considered to be true plant-growing lights. They can typically last for 750 hours, are not energy efficient, and give off plenty of heat, which is why they are not energy efficient.
Fluorescent grow lights
Fluorescent grow lights are used for growing vegetables like leaf lettuce, spinach, and herbs. They are often used as a way to grow seeds, and to start spring plantings as well. Unlike incandescent lights, the fluorescent grow light can last for 20,000 hours. You can also get high output fluorescent grow lights that produce double the light of typical fluorescent lights and are useful in areas that are limited vertically in a greenhouse. You can also get compact fluorescent lights that are smaller and used for growing larger plants. They are designed with reflectors that direct light to plants, thereby limiting the wasted light. They can typically last for about 10,000 hours. The last type of fluorescent lights you can get for growing are high-output fluorescent hybrids that do not emit much heat but also have a high intensity discharge technology that allows them to blend light colors and have plenty of coverage over the plants. The electricity costs of these lights are also much less than incandescent lighting.
This greenhouse is using fluorescent lights to grow vegetables.
High-pressure sodium lights
High-pressure sodium lights are used for the second phase of growth for a plant, typically during the reproductive phase when the plant is flowering. The big advantage of these high-pressure sodium lights is that they enhance the fruiting and flowering process within the plants because of the orange-red spectrum that helps plants in their reproductive process. However, sometimes, due to the poor color rendering of these plants, the plants do not appear healthy when they are growing. That being said, these lights often produce high quality herbs and vegetables. These plants have extremely high energy-efficiency and that makes them very popular to use in greenhouses. One thing to be concerned with is the fact that the HPS lamps emit plenty of heat, and create a distinct infrared signature that can attract signatures. In some high pressure sodium lights, you can use a metal halide bulb. This provides the extra bit of colored light for the plants, creating the perfect spectrum blend. These types of lights cost more and they have a shorter lifespan.
Convertible two-way lamps
Convertible two-way lamps use a metal halide bulb or a high pressure sodium bulb. Unlike the above example, you cannot have both of these lights in the fixture at once. These are very easy to change out when you need to; all you need to do is switch the bulb off, set the right setting, and put the new bulb in.
LED grow lights
LED grow lamps provide cheap, bright, and extremely long-lasting light for your plants. Because these do not consume much power, they are highly beneficial for use in greenhouses during the winter when they may need to be on for several hours. One big benefit of these lights is the lack of heat they emit, which means you have to water less because the soil around the plant will not become dried out as quickly. Of course, make sure you do not overwater the plants. New LED grow lamps use grade 6 watt LEDs that create the same type of power seen in HID lamps. You can typically do the following when replacing your other grow lamps with an LED lamp:
• A 90 watt LED light can replace a 400 watt Metal Halide or HID grow light.
• A 120 watt LED can replace a 600 to 800 Metal Halide grow light.
• A 300 watt LED light can replace a 1,330 watt Metal Halide light.
• A 600 watt LED light can replace a 1,600 watt HID light
When you are using grow lights for your plants to supplement the lack of sunlight you may receive in the winter or fall, keep the following suggestions in mind:
• It is important to remember that the bigger the plant gets, the more light it is going to need. If it does not get enough light, the plant will not grow.
• Vegetables grow best in full sunlight, which means you need to mimic the light of the sun as closely as possible. Fluorescent lamps and metal halide lamps work the best.
• Foliage plants grow best in full shade, and therefore do not need to have grow lights over them.
• Plants need to have dark and light periods, and you should have a timer that switches off the lamps for a time. The amount of photo dark period for the plants will depend on the plant. Some plants grow better when the days are long (more light) and the nights are short (less light), while other plants prefer to have the opposite amount of light.
You should know about light density, measured in lux, when you are using grow lights in your garden. One lux equals one lumen of light falling on one square meter of planting area. If an area is brightly lit, it will be illuminated for about 400 lux.
Temperature Gauges
An often forgotten piece of greenhouse building is the temperature gauge. The temperature gauge is very important, because it will keep your plants from becoming victims of heat damage. Too much heat can cause your plants to die, and a temperature gauge will alert you when you may be running into a danger zone for heat. Sometimes called a temperature monitor, this gauge can be very simple or very high-tech. The simplest type of temperature monitor will emit a beeping noise within the greenhouse and hopefully you will hear it as you are walking by. Higher end temperature monitors will send you a text to your phone when the heat gets too high, or even call you or a backup number you have set up if you are out of town. Going even further, some temperature monitors will alert you about power failures, humidity problems, and even intruders into your greenhouse. You can also get a temperature monitor that will allow you to call the monitor from your phone and get an update on what the temperature in the greenhouse is, no matter where you are in the world.
This may seem like a frivolous expense, but when you lose your plants because the heat becomes too much and no one has opened a vent, you will know just how valuable these are. If you cannot afford a temperature monitor in your greenhouse, then you should at least look at getting a thermostat. You can get a thermostat for only a few dollars, and all you have to do is make the commitment to go check the thermostat every day to make sure that your greenhouse is not suffering from excessive heat. At the very least, you should have a thermometer in your greenhouse.
Humidistat
A humidistat is an instrument that will measure and control the humidity within your greenhouse to ensure the greenhouse does not have drastic changes in humidity, which can be disastrous for your plants. Many greenhouse enthusiasts will combine a humidistat with a thermostat and an air conditioner in order to have complete control of the greenhouse mini ecosystem. A humidistat will be used in conjunction with fans, humidifiers, and dehumidifier. The way that the humidistat will control the humidity within a greenhouse can be done through several methods, depending on the system that you have implemented within the greenhouse.
• Changing the speed, or switching on and off a fan or vent blower in order to bring in more air, or removing air to adjust the humidity.
• Activating or deactivating the humidifier.
• Changing the openings of dampers to change the humidity within the greenhouse.
• Switching a dehumidifier on and off, depending on whether or not the situation requires it.
When the humidistat works, it does so in the following manner:
1. You set the humidity to a comfortable level for your plants that will maximize the growing potential for them.
2. When the humidity level goes below what you set on the humidistat, the humidifier will be switched on.
3. As the humidity level changes within the greenhouse, and returns to the normal level you have set, the humidifier will switch off.
4. When the humidity level goes above what you have set for the greenhouse, the humidistat will kick in and start the dehumidifier.
5. The dehumidifier will lower the humidity level within the greenhouse and, when it reaches the right level, switch off.
Lighting Meter
Lighting meters are an important part of your greenhouse plans, because the right amount of light can ensure that your plants prosper and thrive. With the lighting meter, you will know how much light your plants are receiving, and whether or not you have to adjust your shading or grow lamps. A light meter will measure the amount of light in an area. Often, a light meter will include a computer, which allows you to program alerts if the light changes to something that is not beneficial to your plants. Understanding the amount of light your plants need to survive is important when you are using a lighting meter. One important thing to remember when you are dealing with changing the level of light for your plant is to do it gradually, because sudden changes in light can shock your plants. Plants in general will utilize morning light the best, because the plant metabolism is most active in the morning. Of course, if the region in which you live often has fog in the morning, then the plants are going to get the best light in the afternoon. You should watch your greenhouse plants very carefully to avoid sunburn on your plants. Also, species grown in light that is too low for them will not flower or bloom.
Light meters use the measurement of foot-candles (fc) and you can probably expect the following values depending on how much light is coming in.
• 5,000 fc: Full sunlight during midday will register this high on your light meter. In some lower latitudes, you may find that the level may increase to 10,000 fc. Sunlight going through fiberglass will reach 5,000 to 7,000 fc.
• 4,000 fc: Bright light, about half what the midday sun would read on your light meter. This is often the most efficient level of light for your plants.
• 1,800 fc: Light or dappled sunlight will read this much on your light meter.
• 1,000 fc: Reduced sunlight, which typically does not produce a shadow, will register this much on your light meter.
• 500 fc: When your plants are in deep shade, the light meter will register this much in the greenhouse.
Artificial light will register low on the light meter, but that does not mean your plants are not getting the proper amount of light to allow them to grow. One thing to remember with artificial light is that the light is constant. Therefore, though the light level is low, it is spread out over several more hours.
Automatic Vent Opener
The perfect greenhouse is one that manages itself. When the greenhouse is automatically controlled, you are able to watch your plants grow without worrying about the humidity affecting your plants. One more thing to consider with your greenhouse is the vents. Purchasing automatic vent openers can help maintain the temperature and humidity level within your greenhouse.
A roof vent will provide heat with an escape route out of the greenhouse, while at the same time providing a way for cool air to get into the house. Automatic roof vents have the additional bonus of allowing the intake of cool air to be a gentle flow, rather than a sudden blast of air that causes the temperature to suddenly go down. You do not have to use just roof vents though, as side venting will assist in the cooling of the greenhouse during the warm season.
An automatic vent opener works without electricity because it is self-contained. On a sunny day, heat will build up in the cylinder mechanism of the vent opener. This will cause the vent to slowly open, rather than opening suddenly. When the weather cools, the vent will slowly cool as the air around the cylinder decreases in temperature. It is important that when you do have a greenhouse automatic vent opening system, you use it in conjunction with greenhouse exhaust fans. A greenhouse exhaust fan can help drive air out of the vents, keeping the temperature within the greenhouse at the optimum temperature. If you are growing orchids, chrysanthemums, or tropical plants, then you may need an exhaust fan to maintain the controlled environment within the greenhouse. With an exhaust fan, you should have it constantly distributing air throughout the greenhouse, turning slowly to maintain the air circulation. Condensation within the greenhouse can actually be reduced greatly when you have air circulation.
Ground Cover
A ground cover is a black and woven polypropylene fabric that will control weed growth, while at the same time retaining moisture within the soil. Because it is woven, water and nutrients can still get down into the soil, preventing puddles of water from forming. Although you can use black fabric to help keep weeds away, you may want to think about using white on black, because this will reflect photosynthetic active radiation back to the leaves of the crop, which then will maximize the total energy that the plant produces, helping the plant grow even more. Ground cover is very important in a greenhouse, because, though you may not think you will get weeds in your greenhouse, there is a chance that they can find their way in. As a result, you will want to keep weeds from growing all together, which is why ground cover is very important. Although chemicals are a useful alternative, the fumes could harm the potential growing environment. You can use chemicals but most gardeners are moving away from that in order to “go green.”
When you use the items discussed in this chapter, you can ensure you will get the optimum growing environment out of your entire greenhouse, thereby ensuring you have the most vegetables and herbs possible.
To recap, these are the items you should consider having in your greenhouse:
• Shading: The sun can be harmful for your greenhouse and shading can help moderate the temperature within the greenhouse. Whether you use coating that goes on the glass, a curtain system, or you just build your greenhouse so it is partly shaded by a tree, shading will help your greenhouse and the plants inside.
• Misting Systems: Humidity is vitally important within a greenhouse and therefore you need to think about using misting systems. Misting systems will keep your plants hydrated, regulate the humidity, and provide you with an easy method to transfer fertilizer to your plants, helping them grow even more.
• Grow Lights: If you are in northern latitude, or in an area like the Pacific Northwest where there are plenty of cloudy days and rain, grow lights can be a saving grace in a greenhouse. The grow lights will help your garden grow when there is not much light. In the winter this is especially important. When you choose LED lights, you save money and that will help make growing items in your greenhouse all the better for you.
• Temperature Gauge: If you are not near your greenhouse, how do you know how warm it is in there? The temperature gauge can be as simple as a thermometer or as high-tech as a temperature gauge that calls you when the temperature gets too high. If it is too hot in your greenhouse, your plants will die and you do not want that to happen. That is why something like a temperature gauge is so important for you and your greenhouse.
• Humidistat: This might be something you have not heard of before, but it is important for your greenhouse. With a humidistat, your greenhouse is monitored for its humidity level and you can ensure that if the humidity gets too high, or too low, the humidifier or the dehumidifier is going to kick in and therefore maintain the optimal humidity for your plants.
• Light Meters: Knowing the right amount of light for optimal growth is all part of being a greenhouse enthusiast. A light meter is cheap, and it can give you an indication if your plants are receiving too much or too little light.
• Automatic Vent Opener: One of the most low-tech and easiest things to install in your greenhouse is the automatic vent opener. Using nothing but power and heat, with no electricity, you can rest assured that when things get too hot in your greenhouse, the vent is going to open to help equalize the temperature and humidity. When you add in an exhaust fan, you can ensure there is a constant circulation of air within the greenhouse.
• Ground Cover: Ground cover is something that you may not think of when you are building a greenhouse. Greenhouses keep the weeds out, not bring them in. However, you can bring them in with your clothes, the dirt, and the compost that you bring in for your greenhouse plants. Weeds take away vital nutrients and minerals from your greenhouse plants and vegetables, so you want to use woven black and white ground cover to keep weeds from growing, while also making sure that your plants grow. The white reflects vital light back to your plants, giving them an extra boost of energy as well.
The important thing to remember is that much of the technology discussed within this chapter is completely optional. In no way is it completely necessary to purchase the items previously mentioned in order to have the most successful greenhouse. Although there is a level of convenience in automatic systems, manual options are equally sufficient for your greenhouse. However, utilizing the items covered in this chapter can ensure that you get the most out of your growing experience.