Issue 16


Table of Contents:


1. Chickens and roses

Yes, I know you probably won't believe this. But now there is a commercial operation where chickens and roses are both grown hydroponically together. The company is named Harmony and Roses. In a joint venture, the chickens are a product of a Japanese company named Nature's Harmony and the roses are sponsored by Beall's Roses which produces for the US market. The roses are distributed by Seattle Roses.

The chickens are raised below the roses which are in hanging tables that can be moved back and forth as desired. The chickens are raised on a bed of decomposing straw and chicken wastes.

This way the chickens give out extra heat while the decomposing litter bed gives off carbon dioxide. Both of these are beneficial to the roses. When the litter bed has decomposed to about six tons of nutrient over the course of twelve months the nutrient is used to feed the roses (in addition to regular hydroponic rose nutrient).

The operation is set up so no excess water or nutrient or liquid from the litter bed is allowed to escape to the outside environment and consequently seep into ground water. For the roses, drip irrigation is set to make sure there is no excess water. But if that does occur, the excess will drip to the chicken litter bed below.

The chicken litter bed is tightly sealed at the bottom to keep any liquid from escaping to the outside. This company uses plastic but concrete can also make an effective shield. Excess water is drained away and placed in tank which is periodically emptied.

To allow the chicken litter bed to decompose properly, 8 inch aeration pipes are laid on top of the bottom seal. Then about a foot of straw (usually grass straw) is placed on top of the floor and the pipe. Above that is laid 4 inch aeration pipe which can also transport water. Again, another layer of straw is strewn six inches deep.

Thus in a greenhouse which is 120 feet by 30 feet, you get straw amounting to 40 tons and chicken waste of 25 tons combining together to give the six tons of nutrient mentioned above.

This design yields chickens valued at $7,000 and roses valued at $36,000 for a total of $43,000 per year. Not bad for about a tenth of an acre!


2. Let's talk about CO2

To generate carbon dioxide for your crops, you can either use compressed CO2 or you can use a CO2 generator. The first is usually used for small operations because they don't put out the heat and moisture that generators do. Large commercial operations have the equipment which can handle any excess heat or moisture which CO2 generators put out.

The application of CO2 for small operations is done in a "straight-line" method. The CO2 is released at plant level along with the incoming ventilation (or cooling) air. The exhaust fan (again at plant level) at the other end of the greenhouse will pull out the excess heat and humidity.

So for small operations it's just a simple matter of adjusting the flow of the CO 2 with the normal intake and exhaust fan cycles. After a period of week or two you can examine your crops to see the results which should be quite good.

If you don't see any growth changes, check these other items before you blame the CO2 or add more. Look for high temperature, air which doesn't move properly, a poorly mixed nutrient supply which doesn't let CO2 do its work, disease or bugs. If none of these are present, then check your CO2 application procedures and see what can be done there.

Since plants do most of their growing at night, CO2 should be applied just during the daylight hours. A flow which is continuous is best.

Now about those generators. As mentioned before, they put out a lot of heat and moisture but are very efficient generators of CO2. One good solution is to have the generator "outside" the greenhouse in another location and the CO2 gas piped into the plant growing area.

You can also hang it above the plants - way up above. When all other fans and exhausts are turned off you can have this generator work at short intervals to let CO2 gas fall down to the plants. Then turn the generator off allow the other fans do their work.

Which may well work except chances for too much heat and humidity can build up and you really don't get that much CO2. This so-called "trickle-down" method of using CO2 generators seems suspect when you consider that plants have their breathing pores on the underside of their leaves, not the top side. So where's the benefit?

There is also too much risk of high humidity at night time which can greatly promote disease.

The best choice? The remote area, away from the interior of the growing area.

As would be suspected CO2 generators are best in large high-ceiling greenhouses and/or gardens. It's a good idea to use two generators for large areas because they offer more evenly distributed CO2 and less heat problems. CO2 generators can supply CO2 a lot cheaper than compressed CO2. They just require care and a little planning.


3. Too much heat in the growing area?

Wonder why the intake fan is on the low side of one end of the greenhouse and the exhaust is on the high side at the other end of the greenhouse? Because cool area goes to the bottom and hot air rises to the top. Done properly this would be the least expensive way to keep the temperature inside a greenhouse under control.

But what if the air coming in from outside is hot? Well then you will need an air conditioner or those big water pads you see covering one whole end of a greenhouse which air blows through and is cooled. One way or the other you will have to cool off the air before it reaches the plants.

One of the reasons aluminum tubing or plastic tubing (which also has smooth walls on the inside) are used in greenhouses is because the resistance is reduced and the blower fans operate more smoothly. Exhaust fans are usually on a thermostat which tells them when to turn on.

One alternative to attempting to move the entire volume of air inside a grow room or greenhouse is to use grow lights which are air cooled. Here you have intake and exhaust fans attached to the upper frame of the lamp. This way you move a lot less air and the heated air from the lamp doesn't get into the rest of the room. You also save on CO2 because most of it is in the grow room and not under the lamp.


4. Some criteria for HID lighting

In high intensity discharge lamps (known as HID) several criteria are important to know. They are color rendering or CRI, color temperature, lumens and initial lumens. CRI measures the quality of light. The highest measurement is 100 which is the same as daylight as well as incandescent lights. The higher the CRI the better plants grow.

In color temperature what is actually being measured is the appearance of the light. For example: white or blue-white is 3600 K plus and is referred to as cool light; yellowish and red-white light is 3400K or less and is referred to as warm light; average daylight is 5500K.

What is a lumen? it's the amount of light which falls on one square foot of surface. Every point on that surface is one foot from the light source, such as a light at the center of a sphere with a radius of one foot. Thus 1 candlepower would give off 12.57 lumens.

New lamps have high initial lumen capacity but should be replaced after they have been used for about 60-65 per cent of their life expectancy. They grow dim with use. Needless to say, to grade high on all of the above, the lamp will also cost more. So sometimes, one must choose between one desirable over another to get within a budget.


5. A few odds and ends

A. If you use a solution of 10% bleach be sure to thoroughly rinse out the media after finishing. Bleach residue left behind can burn plant roots. A product like Clearex is good to use also because not only can you clean the media but you can place some in your nutrient reservoir just before harvesting a crop. This will leach out any salts which have accumulated in the tissues of your plants.

B.What about organic nutrients? You can use them but you must first have the media inoculated with the necessary microorganisms whose main function is to decompose and help break down elements into a form which the plants can take up through their root systems.

Organic nutrients are quite difficult to employ (compared to regular nutrients) and they cost just as much. To use hydroponics organically you are going to need a lot of patience and time to get everything the way it should be.

C. Many career opportunities are available to those interested in hydroponics. But bear in mind that commercial applications have become highly technological. Most commercial applications are ten to twenty acres in size. Computerized to the hilt, such applications need skilled managers and operators. Since these are not in abundance within the US, most such skilled workers are recruited from Holland, Israel and even Belgium.

Some universities are beginning to set up course plans designed to meet this need. The University of Arizona and Delaware Valley College in Doylestown, PA already have course plans set up and in action.

D. Once in a while you get some good information from a newsgroup.

Here's one to look at: This individual "sanitizes" his greenhouses every month. He moves out all pots which don't have plants in them, then hoses down all walls and floors and plants with something like hydrogen dioxide. If it's the time of the year when there are insects about, he uses liberal doses of insecticidal soap.

Obviously, he is not much into beneficial insects nor, I suspect, hydroponics. Because he is too much inclined to use heavy doses of insecticide.

But he is on the right track by keeping cleanliness foremost in his operation. If you wait to the end of the season to clean up everything, you'll be to late. You need an on-going program of sanitary measures to employ on a regular basis. And you need to set up that plan now - BEFORE the season begins!


6. Aphids - Bug of the month

These pesky rascals can be easily identified by the small cornicles which stick out from their tails or rear ends. No other insect has this characteristic. They are anywhere from one-thirtysecond of an inch to one-eighth of an inch in length and form small colonies where they all bunch together, including adults and the young which all look alike.

In fact the young are born already pregnant, like embryos inside of embryos, and that's why they can devastate a plant growing area so quickly.

Though their main purpose in life is to feed on the juices of tender plant growth, the diseases aphids carry are what can ruin a crop very quickly. Leaf distortion is the main sign of aphids being in the vicinity. Not to mention the "honeydew" which they place down on leaf surfaces. This honeydew should be hosed down as soon as it appears. Otherwise, the honeydew will be covered with a mold which will choke the plant.

Aphids are pear-shaped and come in a variety of colors. There seems to be an aphid for every plant. In any case there's an awful lot of them around. If you see leaves which are curled or discolored or even puckered you can just about place a sure bet that there's a large colony of this little rascals feeding close by.

But to the rescue!

Ladybugs are the prime aphid demobilizers. They eat them by the ton, so to speak. Of course, lacewings do a fine job too as well as aphid predators and aphid parasites with the predators being the best choice for an entire season.

You can start out with ladybugs and green lacewings and then continue with aphid predators. My book on "Beneficial Insects - How to Mass-Rear for a Profit" may be of interest to those of you who might like to grow green lacewing. The book tells you how. Just go to http://www.mayhillpress.com/insects.html for the details.

The only problem with ladybugs is they like to wander off into the "next pasture". You can slow this tendency down by spraying them with diluted soda pop which will "glue" their wings for a week or so. Meanwhile they'll be eating as fast as they can and decimating the aphid population.

If you use these beneficial insects for control you will not have much to worry about when it comes to aphids.


bsaffell@mayhillpress.com...Last Update: 52008 copyright 1996 - 2008 by Hilmur Saffell

They are as follows:
"How to Start on a Shoestring and Make a Profit with Hydroponics"
"Big Dollars Growing Gourmet Salad Greens"
"Beneficial Insects - How to Mass Rear and Make a Profit"
If you would like a copy or copies of your own,

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