Issue 5
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Table of Contents:
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1. What's this about NFT?
NFT? What's that? Nutrient Film Technique, that's what. If you're not in the know on this, you might want to read the fundamentals on pages 90-93 in my book. "How to Start on a Shoestring and Make a Profit With Hydroponics", amply described at (http://www.mayhillpress.com/hydroponics.html). This article is for those who want to know more about it and how to make it work.
And according to one prominent Australian grower, NFT is the wave of the future. NFT is a hydroponic method of growing which was intro- duced by Dr Alan Cooper of England. His hope was that it would be the savior of the world, especially the third world. Our Australian grower thinks so too but he also thinks that most people are going about it in the wrong way. In fact he bluntly states that most people are going about growing hydroponically in all the wrong ways. (By the way, Australians and New Zealanders are quite big on hydroponics.)
The problem with most growers is they don't pay enough attention to the oxygen needs of plants. They too often allow NFT channels to sag and puddle. Where the puddle occurs is where the damage is done - because the roots get water-logged. Too much water or nutrient and not enough oxygen. In addition to that, growers send too much nutrient at a time down an NFT channel.
To get the best results from NFT you must have the following:
Too many growers are using PVC piping for NFT. According to our Australian grower, this is asking for disaster - or at least poor growing conditions - as the PVC pipe does not have a flat bottom. Flat bottom is very important in NFT. Pay attention to that and prosper. Gully or channel bottoms which have uneven surfaces will pond and therefor cause ponding and poor growing conditions.
How does one go about getting that flat bottom?
The floor of the greenhouse or growing area must be graded to where it is
absolutely flat with the downhill slope at a grade of 1:40 (1 inch to 40
feet or 1 1/2 inches to 60 ft). It must be so evenly graded that no
depressions of any kind occur. In other words: absolutely flat.
You can then pour on a skin of concrete at least 1 cm thick so it can be easily worked. This will seal off the area to all soil diseases.The concrete should be poured all at once and then screeded and then trowelled to a smooth finish by using power floats. The expansion joints should be cut as soon as the concrete permits and then cleaned and filled with a silicon or other suitable product.
After the concrete is fairly hard, etch it with a weak solution of acid (usually phosphoric) and then wash it with lots of water. After that the floor can be painted white which will reflect heat back to the plants. Day and night the concrete floor will absorb and release heat to plant root systems.
This is the way the growers do it in New Zealand and it makes a perfectly flat floor on which you can place your rigid triangular NFT gullies or channels. The beginning cost is a bit high - but this kind of setup can last for years and be very easily cleaned and maintained.
Why NFT and not other setups?
According to our Australian grower, here is a short list of things that can go wrong with large commercial setups which are not rigged in correct NFT fashion. Small "hobby" systems may get by, but not the large commercial.
Now though these setups will work fairly well on a small scale, a commercial operation using the same methods could be courting disaster. In any case, according to our Australian grower, NFT, when done correctly, can furnish bigger and better crops and a lot more easily.
One more thing: try to find a polythene which is black on one side and white on the other (they call it Pandafilm in Australia). The black when used as the inside cover of your NFT triangular gully will keep out light which promotes algae growth. The white side will reflect heat away from the plant, especially in summer months.
Well what do you think? Drop us an email at mailto:bsaffell@mayhillpress.com with your comments. I'd like to set up part of this newsletter for such comments from time to time.
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2. This and That...
As a followup on the NFT article above, an American CEO of a large hydroponic supply company suggests that, though NFT is an admirable system, what happens if the pump goes down? That's right- you lose the crop. Another system, called aero-hydroponics, has the roots with their tips under a moving stream of nutrient and the upper sections of the root systems being misted with nutrient spray. So if the pump goes down, the plants can survive for awhile.
A grower in the San Francisco area gets about $4.00 per pound for his tomatoes. He doesn't believe in shipping long distances as some of the flavor is lost. So he sells to the high end market where people will pay for quality and taste. These would be health food stores, high-end grocery stores and even the farmer's market where he has a ready and eager audience awaiting his arrival each weekend. One way he does this is by conducting "taste tests". Once the prospective customer tastes the tomato, he's usually hooked.
In Hawaii, a grower has a hydroponic greenhouse built somewhat like the one pro- posed in our book on hydroponics. (See pages 70-80) All he has is a long wooden frame house with one layer of polythene on the roof to fend off heavy rain. And as suggested in my book, the sides are left open. This grower uses raceways with floating styrofoam rafts to grow his crops.
Many strawberry soil growers are going to have governmental problems if they continue to use methyl bromide as a fumigant. Hydroponics is the answer for them where they can grow high quality crops without harm to the environment.
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3. Rearing Crickets (Part Two):
Fundamentals:
Different size boxes will be needed for different activities. Boxes which are used for holding (like for sale later on or for further production) are made of wood, sometimes fiber board. The boxes have hinged screened lids with a heat supply. They are about 2 ft square by 1 and 1/2 ft deep. Such boxes will hold in good shape about a thousand adult crickets, which can be used for breeding or for sale.
If you want maximum egg production you must not let the temperature vary more than two degrees one way or the other from 86 degrees Fahrenheit. This will ensure the largest sized growth of adults. Keep the temperature at this mark throughout the breeding period. Pans for egg laying which hold a thousand breeder adults can be placed inside the boxes described above.
Heating can be maintained in the boxes by having a 60 watt light bulb in each box. This light bulb can be switched on and off by using a thermostat such as that used for chick (chickens) breeding. This is the cheapest and effective way to go. Bear in mind that a fan should also be used in the vicinity to keep down the humidity which can cause disease.
Some growers use fuel oil heaters which are thermostatically controlled. This method is more expensive, but you can heat an entire room containing several breeding boxes.
Crickets, like all animals, require their space for crawling and general getting about. You need extra space besides what's contained in the box. An excelsior which is wide-cut comes from the supplier which, when dried out, allows ample crawling space. Don't use ordinary thin-cut excelsior as it breaks down too easily.
What kind of food an water do crickets need?
Oatmeal is a good feed as well as mash used for starting chicks. Be sure the meal is fine-ground. Sieve out the larger particles and discard. Buy only what you need for any given breeding period. You don't want too much as it may spoil or become infested.
Too make sure there is no infestation, you can heat in an oven to 200 degrees Fahrenheit for a couple of hours and then allow to cool. Crickets like their food at hand all the time. Make it a habit to check the feed and the crickets every day or so. You can also place sliced apples in the breeding boxes to provide extra food and moisture.
Some extra care must be taken with watering to prevent younger crickets from drowning. One way to do this is to use quart-sized fruit jars. The jars are placed on small square wooden platforms which are built so that the jar level is high enough to allow small crickets to crawl underneath. You could make the square platform on pegs (legs) so it would be easier to remove and replace the jar and the small platform without crushing young crickets.
Each jar is placed on a cellulose or rubber sponge which fits tightly around the rim of the jar and only lets water out when the sponge begins to dry. You can get a better idea of how this works by visiting a pet shop or a bait shop which may have such watering devices. In all cases, the jars and their sponges must be cleaned and washed every 4-6 days.
Hatching, Grading and Shipping:
Any pan which will not rust and which has a rough surface will do the job. The media in the pan must be moist and can be composed of good soil, peat- moss or rotted sawdust. Just as you sterilized the feed to prevent pests and disease, so you should also use the same procedure and temperature to sterilize the media.
Water until damp but not wet. Sprinkle the top with water when needed. Do this until all the eggs in the pan have hatched. The normal size pan used for hatching (breeding) runs about 3 inches deep x 5 inches wide x 12 inches long. This size will allow you to control the number of crickets you want to hatch.
When it comes to grading, you can do like some growers do: just allow eggs to be produced for two days and stop the process there. Then move the egg laying pan to the hatching room. Since they are not counted individually, for convenience the normal quart jar holds about a thousand adults which is the size fishermen prefer. Use smaller jars of pint size for smaller quantities.
If you want more production from the same hatching period, then you will have to do some grading to separate the adult from the young. One way of doing this is to take a large tin can, the restaurant type size. Clean thoroughly and punch holes in it all around with a 20-penny nail. This hole size will keep the adults in side and let the young out which you collect by using a feather to brush them into another smaller can.
The adults can be placed into holding boxes - be careful not to crowd. The young are placed back into the breeding section and eight to ten days later the process is done again.
They are sold and mailed to buyers at one thousand to the box. These boxes are about 10"x10"x10" and are usually cardboard with openings screened for air access. You may or may not need a mailing permit . The USDA and/or the post office can give you details on that. It sometimes depends upon how far you have to ship and if it's state to state.
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