Issue 15
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Table of Contents:
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1. Electrical do's and don'ts
Make certain EVERYTHING is properly grounded. The reason why is if you accidentally touch a grounded circuit you don't receive a shock. Why? Because it's easier for the current to go to the grounded wire than through your body. BUT if you are standing in water chances are you will be electrocuted or severely injured. Even if the wire is grounded, water allows the current to flow through your body more readily.
Always unplug an electrical product before you decide to service it, especially industrial timers. In addition stow all electrical wiring off the floor or where they won't accidentally get in touch with water. This will take some planning because a greenhouse contains a moist climate. It goes without saying that you don't want to take any shortcuts here - no cheap wiring for example.
Keep in mind that the capacitor for HID lighting still has an electrical charge AFTER its has been unplugged. Use protective electrically insulated gloves for servicing such units. And if you're using a lot of these HID lights, a timer panel should be used with each separate light. You don't want to overload the circuit and cut off a main breaker.
Ballasts can manifest lots of heat - keep them separate and away from flammables.
All lights should be hung with chains as extra support. They should never be hung by their wires.
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2. Growing lights which are water cooled
These lights can be very handy. You can construct a mini-indoor culture by using them. Some companies manufacture special units based upon the use of growing lights which are water cooled.
Like a miniature greenhouse, such units would be like boxes with everything needed for plant growth contained inside. Such as fans, watering equipment, controls, etc.
The advantages are considerable, albeit on a much smaller basis than the regular large greenhouse structure. In effect this is a good idea for supplementing kitchen needs from inside the house.
You get more productivity from a smaller unit of space. You can add or detract CO2 with ease. And you can control insects and disease more readily. Less ventilation is needed, and your crop is isolated from the outside world. And, just like a greenhouse, you can operate year round.
You can even set them up in modular fashion - if you don't mind the expense. Bear in mind, though, that this is a trend toward the hobby aspect rather than large-scale commercial production. Nevertheless, NASA has been experimenting with this idea for some time now for future space colonization.
One big problem: how to get rid of the heat generated by the lights? This is where water cooled lights come to the rescue. The heat can be gotten rid of by running a garden hose from your city water supply and let the heat flow out the other end with the water. This would be a cheap and effective method for those with just a few lights to cool.
You can also recirculate the water by using a heat exchanger. Another way (to save water) is to hook up your grow room in line with other water using devices which when turned on would automatically help cool the lights. Some people have even used the waste heat from the light to help heat a pool. But if it's a swimming pool, you're going to have to have a lot of grow rooms!
If you have a stream or lake nearby, you have the best and easiest way to get rid of the excess heat from the lights. You'll need a garden hose or piping of some sort, a reservoir, a filter and a pump. Nothing could be simpler.
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3. A few items of interest
A. Recent research indicates that adding an organic fertilizer preparation to your nutrient supply can mean extra benefits not only to the plants but to you the consumer. Even plants grown under optimum conditions will benefit.
Bear in mind, however, that the organic preparation must be like a tea and, if from manure, must come from a completely composted bin where no pathogens can be introduced to the plant systems.
B. Do not soak your rockwool in nutrient solution as it will cause the seedling roots to rot. Just dampen well with water before setting in the seedlings. Keep in mind that rockwool has a tendency to get too damp at the bottom.
C. There's a new mylar film put out by Nielsen Enterprises, 3019 S 256th St, Kent, WA 98032 253-941-7281.
It's supposed to reflect 90% and more light back into the greenhouse or structure where you intend to use it. Could be very effective for hydroponic situations, especially in the Pacific Northwest where adequate light sometimes is a problem.
D.Aquamist maintains that aeroponic misting makes plants grow and produce faster than ordinary or other hydroponic growing techniques (see related links at http://www.mayhillpress.com/link.html). This growing technique can be compared to a tropical rain forest where moisture and nutrients reach the roots through a fogging process.
E. Ozone is a great deodorizer because it stops the odors where they begin, but it has its problems. And Ultra Violet light seems to have the edge when it comes to room deodorization. It's cheaper than the corona discharge units used to make ozone, takes less maintenance and more effective. It also takes less energy than one 100 watt bulb.
F. Mesclun mixes come in various guises, depending upon the consumer. Although most mesclun mixes have lettuces as a base, the leaf-type lettuce gives more color and grows faster.
Perhaps you like some bitter taste. Then add endive, dandelion, radicchio or chicory.
For some spice, use escarole, radishes, nasturtiums, some mustard or watercress.
Exotic additions could be the delicate mizuma or even purslane.
If you would want a hint of herbs, consider adding basil, garlic or onion chives. You can also use chervil, coriander, lovage, dill angelica, anise, chard and spinach.
It's your mesclun mix. Fix it to suit your taste. And remember: you can grow all of these without much extra effort on your part.
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4. Much ado about bugs
Nitrogen for plants comes in two available forms: ammonium or nitrate. Some scientists feel that the availability of nitrogen in a plant has a direct effect on aphid growth. This would seem to indicate that nitrogen from nitrates would be more available to the plant system and therefor be linked directly to aphid population growth.
That said, the best pest management program you can devise is one you will stick with for the long run. Your plans should eliminate the short pesticide (chemical) fix and be based on beneficial insects which would be eventually more profitable.
If you use pesticides to kill one pest but end up with other types of pest, what have you accomplished? Even if you insist on using a pesticide, you can have a backup beneficial (after the pesticide has dissipated) to take over until harvest time.
Sometimes, however, it is difficult to get employees to understand the importance of what you're doing. Changing programs is disturbing to most of us, and it takes time to re-educate.
Yellow cards which are sticky will help. Here you can see the evidence of what's happening. And it's a good preventative measure too. Careful monitoring of the plants by the employees will show after a short time after beneficials have been introduced that the plants are now pest-free.
Employees need to be encouraged to hang in there and wait for the final results. Of course this is true with any procedure you initiate, not just the introduction of beneficials for a pest-free environment. We all need to see in order to believe.
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5. Spider Mites - Bug of the Month
This is our new feature article. Since bugs of all kinds sometimes threaten our crops, it's a good idea to know what they look like and what beneficial(s) will attack and eradicate them.
Spider mites are one of the most prevalent pests in the greenhouse. Years ago, when I was managing a nursery in Houston, Texas, I used to hate to see the trucks come in with deliveries of croton and areca palm. These plants were almost always infested with spider mites. Grown in the fields of Florida, they were wide open to attack.
It was always a pain in the neck to cover the plants properly and use the proper insecticide without burning the leaves. One manager, my former boss, did just that and wiped out an entire shipment of areca palms. You can bet management had to change their upcoming ad with as much haste as possible. And there was a grower in Florida who received a good tongue lashing.
How do you know you have spider mites on your plants? By examining the underside of the leaves where, with good eyes, you can see the tiny mites, shaped like ovals, running here and there. In extreme situations you will see a fine web on top of the plants while the leaves will either dead or turning brown.
Two-spotted mites are the most prevalent. There are two spots, one on each shoulder while the body can be yellow or tan or green. But like I said you need good eyes or an eyeglass to see all of this.
One of the scary things about spider mites is that they can become dormant in winter and find places to hide in the greenhouse or growing room. Even if you think you have eradicated them they will come back, either on the wind or from their hiding places. They can also be carried in on someone's clothing. That's why good commercial growers are so adamant in keeping things clean.
What's more, those few which do get inside the growing area don't take long to increase their population. At 70 degrees Fahrenheit, it takes only 2 weeks to produce one generation. Put that temperature at 85 degrees Fahrenheit and the population grows at double the former rate.
With this sort of condition, YOU NEED HELP!
To the rescue comes our beneficials, such as predatory spider mites which are the same size as their prey only nimbler and faster. If you haven't waited too long and let things get out of hand, within four weeks you can have the spider mite problem under control.
The predatory mites will continue feasting until all or most of the spider mites are gone. And you can go on to other problems.
One insectary which provides three different types of these predatory mites recommends you release them at the rate of 30-50 per plant, depending upon the degree of infestation. The more predatory mites you purchase from them the faster you gain control over the spider mites. And if you're growing ornamentals or foliage plants you will want the fastest control possible.
You can count the spider mites you have on one plant and then plan for 1 predatory mite for every 15-20 spider mites. Estimate the number of plants you have and multiply, then divide and, presto! you have the number of beneficial predatory mites you need to get control.
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WE HAVE THREE BOOKS THAT MAY BE OF INTEREST TO YOU.
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"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"
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