Issue 18
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Table of Contents:
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1. A word of caution about hydrogen peroxide
Although I stressed the specifics of the handling of hydrogen peroxide in our last issue, we want to make certain everyone understands the dangers that are inherent with high concentrations of hydrogen peroxide.
Here is a cautionary memo from Ray, one of our readers:
"I read your latest hydroponic newsletter about hydrogen peroxide. Very interesting. Having some background in hazardous materials though, I know about some of the dangers of higher percentages of hydrogen peroxide that you mentioned. You may want to warn people to be sure and read up on how to handle the material safely. At the higher percentages, it will react with organic materials.
It has caused fires before. Higher percentages than you mentioned can cause leather shoes to catch fire. Also a small amount of impurity in a container of higher strength can cause the peroxide to react violently.
The idea you wrote about sounds great, but you may want to warn people that they need to understand about the higher percentages of hydrogen peroxide."
So there you have it: use the chemical with care.
By the way, this newsletter is always open to sensible comments from its readers. So if you have something to say which may help the rest of us, please feel free to drop us an email or two.
I'd rather setup a discussion exchange in this manner than just opening a chat group or bulletin board. I also am personally taking care of my wife who has advanced vascular dementia (similar to alzheimer), so I don't have that much extra time.
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2. Enzymes and hydroponics
Enzymes have been used for years in soil agriculture to break down nutrients and condition soil. In hydroponics their use has been confined to one or two enzymes blended or occurring in nutrient solutions.
There is a new product, composed only of enzymes, which the distributor claims prevents root rot from fungal and bacterial sources in hydroponic systems. He also states that it reduces algae growth and may help enhance growth and yield in tomatoes and certain other crops.
The product is produced by natural fermentation, contains no chemical additives and is nearing the end of trials for organic certification. The enzymes have been marketed and used by growers in Canada for nearly a year now with good results.
It is being distributed by Steve Butterworth (mailto:sbusa@wayfarer1.com). Although Steve is targeting the distributors and commercial growers, he has promised to sell small quantities (1 liter bottles) to anyone who mentions having heard about Generic Enzymes in this newsletter. Contact him at his email address and he will email you the information about this new product for hydroponics.
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3. Grandpa's garden
In central California, a very successful hydroponic operation maintains two strategies in its growing operation. One strategy is to serve as an educational and intern facility. The other is to provide production for 50,000 lbs of tomatoes, all hydroponically grown under the label "Grandpa's Garden" to a very selective list of stores and customers.
By trademarking the product and making certain of its high quality, this operation has built a strong customer base.
How are these tomatoes grown to get such perfection and to be in such great demand? This hydroponic facility uses perlite bags with a timed drip system. How the nutrient is delivered to the drip lines is regulated by the amount of sunlight, the crop's age and the amount of fruit ripening on the vines.
Bulk fertilizer is mixed to specific requirements and then mixed in the water supply at a rate of 100 to 1. Only natural sunlight is used. Annual tomato varieties of an indeterminate nature are used.
Like all successful operations, attention to detail is required. The following tasks are done for every plant on a weekly basis: pruning of clusters, suckers and leaves as well as maintaining one single fruit bearing stem which must be clipped and lowered by leaning in one direction with all the other plants doing the same. This method gives top production of the fruit involved.
The selling process is simple and profitable. The tomatoes are wholesaled to the top restaurants and stores in the surrounding area. Special efforts are made to acquaint produce managers of the handling and care of Grandpa's Tomatoes.
Those tomatoes which are not of premium quality are sold at a stand set up in front of the producing greenhouses. Here, the locals and passersby can get a great tomato with great taste.
The growers at Grandpa's Garden believe in a no waste philosophy. The stand outside the greenhouses is also used to sell herbs, radishes, lettuce, carrots, salad greens, cucumbers and squash which are grown outside in beds.
These beds are used to get rid of any excess nutrient waste from the greenhouses. Since the growers overfeed their tomatoes by 10 per cent, keeping the grow bags saturated with nutrient, some nutrient will go to waste. What excess nutrient is left over from the outdoor beds is run to an orchard or other gardens. So there is little if any waste.
The plant waste is vermicomposted. Here worms help break down the plant material to make excellent compost. Worn castings and worms are then sold to market. As you can see, everything is turned into a profit and with no waste.
To offset the high winter heating costs, Grandpa's Garden has available an excellent supply of almond shells which the owners can buy at fifteen dollars a ton and use to heat their greenhouses. A ton will last a week. Backup propane furnaces are also available if needed.
To reduce the number of insects coming in from outside, insect netting was placed at the opening ends of the greenhouses. This enabled the growers to use beneficial insects to control insect infestations.
The water is purified at the well with an ozone generator. The ozone kills both viruses and bacteria. Filters are placed in line to remove any particles or organic matter.
All in all, I'd say Grandpa's Garden is a very fine setup indeed!
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4. How to survive with hydroponics and aquaponics
How about doing both with watercress, tilapia and lettuce? How about doing it with 10 greenhouses for a total of 33,000 sq ft or 3/4 of an acre? All of it integrated into one system?
The owners of a small farm outside Wichita Falls, Texas have got the secret to surviving as a small unit in their fight against large corporations. And they do it all in a climate which ranges from 5 degrees F below freezing to 115 degrees F in the summer.
How do they do it? First off, the greenhouses are designed to stand up against high winds and heavy ice and snow loads. For insulation, each greenhouse is covered with a plastic skin which is double and inflatable. Thermostats control the fans inside as well as the propane heaters. Automatic shutters are rollups. When the fans go on, the rollups go down.
In this climate, lettuce is an ideal crop, It likes cool weather. However when summer comes, you'd better keep those fans going. I know - I used to live near Austin which is just about 300 miles or so south of Wichita Falls. And like I know how important a good backup generator can be.
But temperature control isn't all there is to growing lettuce. You have to keep in mind the hours of light you will get as well as the intensity of the light.
The greenhouses used at the Wichita Falls farm are shaded with layers of lime. As the heat gets stronger, another layer of lime is sprayed on top of the plastic roofs. When the weather starts to cool, the lime is allowed to wear itself away. The plastic coverings last about four years and then have to be replaced. Which is pretty good for plastic of this nature.
The lettuce is grown in fiberglass pipes with the NFT method and occupies five greenhouses. One greenhouse is used for seedlings which in this case is Ostinata RZ. This is a Boston variety which has tight heads in winter and is more leafy during summer.
Other varieties of lettuce are also grown, such as baby lettuce and any others which may be in demand.
For nutrient, the owners of this operation mix well water, tilapia waste water and other ingredients. The watercress gets a weaker solution. When summer comes, the nutrient is given in the evening to slow down tip burn.
There are four greenhouses devoted to watercress. This setup is striking when you first see it. What seems to be a long table of flood and ebb is instead a series of tables over which the nutrient flows over a table and down to the next. Like a series of waterfalls!
The tilapia is the latest addition. They are housed in a large rearing tank big enough for 13 to 17 thousand fish. If you keep the water in fair shape and feed them well, tilapia will multiply rapidly. They will even tolerate water which is not as good as it should be.
Because of extraordinary attempts to keep everything clean, there are very few pest problems. For the watercress, beneficial insects are used as well as other biological agents. Pythium is corrected with 3-4 ppm of hydrogen peroxide.
What makes this operation so successful is the marketing tactic of aiming at the quality restaurant and upper end market where the buyer is looking for quality and doesn't mind paying a premium price for what he gets.
With that in mind, right now might be a good time for you to visit my site at (http://www.mayhillpress.com/hydroponics.html). Because a lot of what these folks in this newsletter are doing is explained in more detail in my book on hydroponics.
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5. Thrips - Bug of the month
They like it hot an with low humidity. If your greenhouse is in this condition, then you may well be putting your plants at risk for thrips who thrive in this kind of climate.
What do thrips look like? They are tiny and slim, only one tenth of an inch long. Like tiny worms - but these worms have legs! The adults have wings so they can get about and infest quite easily.
What kind of damage do thrips do? A few of them won't do much harm, but a large colony can knock your plants for a loop. Thrips will rasp and scrape your plants new leaf surfaces where the leaf is most tender.
After a short time you will see leaves which are dotted with small spots, usually yellow in color. The black specks you see is their fecal matter.
Though there are hundreds of different kinds of thrips, they all do about the same damage and they all act about the same. There are two main kinds of control. Most thrips go "underground" in theirpupae cycle. Predator nematodes can be used for control in this situation. ("Underground" in the greenhouse means down into the rockwool or any other media you happen to be using.)
Bear in mind you'll have to use the nematode strategy more than once (for about two months), because the adult thrips are not killed. So use Safers Soap to control the adults.
Some thrip varieties pupae inside the plant leaf itself and are best controlled with thrip predatory mites. Their tell-tale mark will be small volcanic or dimple eruptions on the surface of a plant leaf.
Environmental controls are good also, such as having a greenhouse with temperatures well below 90 degrees Fahrenheit and above which thrips love. (By the way, what in the world are you trying to grow at ninety degrees?) Thrips don't like high humidity either. So all you have to do in this case is grow plants which like temperatures and humidity in the middle range. (Lots of plants don't like high humidity.)
Other predatory insects you can use for thrip control would include ladybugs, lacewings and pirate bugs.
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"Beneficial Insects - How to Mass Rear and Make a Profit"
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