Thursday, January 04, 2007

The Mighty Force of Nature vs. our Greenhouse

You’ll never hear Chuck or I speak disparagingly about the scientists who are trying to warn us about climate change. Especially not after what Mother Nature had in store for us this past week.

It started off very reminiscent of that Winnie the Pooh cartoon, “Blustery Day.” Dried leaves started blowing all over the place and the occasional small tree branch was seen flying.

It grew into a full-fledged windstorm with hurricane-strength winds gusting to 65 miles per hour. Our poor greenhouse had withstood a snowstorm, a power outage, and torrential rains, but this was to be its true test of endurance.

You might remember that we produce 400 heads of Boston lettuce a day in our 3,000 sq foot Quonset-type greenhouse, which is covered with a double-layer of polyethylene. I thank my lucky stars that I stuck to my guns during the planning stages and insisted on galvanized steel supports. Chuck wanted to save money and go with aluminum.

The other thing I made sure of was that the foundation anchors went extra deep into our concrete flooring, even though our neck of the woods doesn’t usually get winds over 50 mph. The poly fastening system used to attach the greenhouse covering to the computer-bent framework had to be extra strong as well.

You have to make sure prior to the strong winds that your door and any openings are firmly shut. Otherwise, the wind grabs the entire structure and your covering becomes a sail.

I’ve seen glazed glass covered greenhouses with half their panels missing after a storm, with the materials strewn as far as 60 feet away.

The other danger is knocked-down trees. In spite of the temptation to surround your greenhouse with shade trees, it’s best to be at a distance from them. Nothing ruins your business quicker than a fallen cedar destroying your greenhouse and with it your cash crop.

A large branch did fly and hit the side of our greenhouse, but luckily it had soft needles instead of sharp protrusions, so it did not puncture the polyethylene. Besides, the material is pretty tough, even though the projectiles in this devastating storm were flying around like pieces of shrapnel.

I heard mention of the impending storm on the 11pm TV news so I drove immediately to the greenhouse to make sure that all the openings were properly fastened.

Also, I thought it prudent that the water and the power should be temporarily shut off, in order to prevent a surge of electricity from frying our sensitive equipment or a rush of water coming in to create havoc on our Nutrient Pond.

I had about an hour before the storm hit, so I decided to make sure that the feeding of our lettuce continued uninterrupted while this emergency was taking place. So before I shut of the electricity, I measured the parts per million of our nutrient solution.

At this stage of their vegetative growth (our crop is in perpetual vegetative phase) the mature plants near the harvest end of the pond require a ppm reading of 1300, but the solution at that point only read 1100 ppm. So I had to add some ingredients.

Our basic fertilizer is Grow and Micro (without the Bloom—we do not want our lettuce to start flowering). I added some of our basic fert, plus Humic Acid and Fulvic Acid, two dynamite supplements that mimic the rich humus of the world’s best soil, since they are derived from a layer of dense, organic “leonardite” that is mined from on top of some coal beds.

I measured again, and found that this manoeuvre raised the ppm of this section of the Pond to 1250, still not quite enough. So I poured in enough Scorpion Juice, to raise the level to the desired 1300 ppm.

Scorpion Juice imparts induced systemic resistance to many pathogens and pests, and thus is an invaluable tool in a horticulturalist’s satchel.

Prior to shutting off the reservoir pumps, I made sure that the pH level of the pond was at the desired level of 5.6 for our hydroponic crop. The reading showed 5.0 pH, which is too acidic, so the number had to be raised by adding the proper amount of pH Up, a very fine Advanced Nutrients product.

By this time the wind was literally howling outside and I shut off the power just in time. You never know with these freak storms, some electrical charge could build up and lightning could strike the sources of our power, so it’s best to be on the safe side.

It was almost two in the morning and Chuck arrived, out of breath. I only opened the door a crack to let him in and shut and locked it immediately after. We watched as Mother Nature gave us a spectacular show.

We also prayed. Although Chuck professes to be a non-believer, from the corner of my eye I saw him make the sign of the cross as the fierce winds shook our greenhouse to its very foundations.

As it is, we are very lucky. Aside from a few minor rips, no major damage was done to either the structure or the double-layered covering of our greenhouse. But you can bet your fresh-picked salad that I insisted on galvanized steel construction for our two planned greenhouses, and Chuck didn’t fight me this time.

I also won with regard to growing pak choi in one of them, while Chuck decided that specialty lettuce should be grown in the other one, instead of spinach. “No use growing a difficult vegetable,” was his entire argument.

Specialty lettuce is the crinkly kind, usually with a red tinge around the edges. Some people add it to their salad to provide color. Since many people consider Boston lettuce as part of the specialty family, Chuck felt more comfortable deciding to grow another type of “specialty lettuce,” rather than yet another unknown vegetable.

Pak Choi, sometimes known as Bok Choy, is also called Chinese mustard cabbage. It can be sautéed for five minutes and with the addition of stir-fried tofu, it can make a complete meal.

It is a popular vegetable in the ethnic Chinese communities in many cities around the world, including the urban center in our vicinity. I’ve researched the market thoroughly and have already lined up buyers for 600 heads of pak choi per day.

Our planned greenhouses will be slightly larger than our present one to enable us to produce 50% more of our cash crops. We’ve done the math, and our daily sales will make the construction of the new facilities cost-effective.

But you can firmly bet that the anchors securing the framework—the bow, rib-brace, purlin, and cross-brace—of our planned greenhouses will be sunk extra deep into their solid concrete foundations.

We inspected the entire structure the day after the storm and found that some of the locking pieces had come loose, while a few scrapes and tears needed patching. The framework withstood the onslaught quite well, only some nuts and bolts had to be tightened afterwards.

Also, every time the power is shut off the computer-controlled timers and logarithm calibrations have to be reset. It’s like having to reprogram your DVD player and VCR after every power outage.

Brand new pH and ppm and EC readings had to be taken to make sure that the continuous operation of our Boston lettuce production line was not impeded. I’m glad to report that with the help of the irreplaceable Advanced Nutrients products that we use, our daily output of 400 heads of lettuce was not interrupted—neither did the quality of our produce suffer.

A lucky start to the New Year, indeed.

posted by silvio @ 9:21 PM   2 comments


At 1:46 PM, Blogger Cody said...

We are new to the commercial hydroponic lettuce growing business and were wondering if anyone could help us in finding a wholesaler who would be interested in buying our lettuce. Presently we are about to start an operation that yeilds us 12,000 heads of lettuce a month and we have the capability to do double that. If anyone knows someone we can contact who would be interested in buying our lettuce please let us know. All of our lettuce heads are individually packaged in lettuce crispers with sticker logos. We can be reached at Thank you,
Cody Harris President

At 1:48 PM, Blogger Cody said...

Do you know where I might get rid of 12,000 heads of hydroponic lettuce a month?


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