Wednesday, March 14, 2007

Three greenhouses going full tilt ahead!

The two brand new, 5500 square foot greenhouses are finished and in operation. We have gone through the first ten days of pak choi and specialty lettuce production. In this blog posting, I’ll concentrate on what we do with the pak choi.

Day 10 is for transplanting. We’ve treated our seedlings with No Shock and Jump Start, in order to minimize the stress of moving them from the germination area to the main Nutrient Pond.

Each seedling gets 42 square inches of space to grow in, with 37 pak choi plants per square meter polystyrene board.

Daytime temperature in the greenhouse is kept at a steady 25º C (77º F), and at night the temperature is allowed to drop down to 20º C (68º F).

The pH of the Nutrient Pond is automatically adjusted to 5.8 by adding small quantities of pH Up or pH Down, whichever is necessary. The EC of the Pond should measure 1.2 and the dissolved oxygen should be 4 mg per Liter.

Relative humidity goes from 30 to 70%, depending on the respiratory cycle of the plants, as well as the amount of CO2 being generated. Since the ppm of the solution is kept at 840 ppm (equal to EC 1.2) the computer-controlled system automatically sets the CO2 generator to 840 ppm as well.

These growing condition remain the same from day 10 to harvest, for the pak choi.

On Day 17 the leaves of the pak choi plants have filled the canopy and respacing is required. Polystyrene boards with 18 three inch holes are used to put half as many plants per square meter as before.

Piranha, Tarantula, and Voodoo Juice are added regularly at half strength to the pre-mix tank and then the reservoir, in order to colonize the roots of the pak choi plants with beneficial fungi, bacteria, and microbes, respectively.

In addition to their basic diet of Micro and Grow, we also add the usual supplements to the nutrient solution.

These include Grandma Enggy’s Humic Acid and Fulvic Acid, as well as her Seaweed Extract. They add the all important organic ingredients that simulate the composition of a rich, black, humus-like soil, only in liquid form.

Seaweed Extract is like a shot of multi-vitamin (as well as natural antibiotics) while we also add B-52 which is a B-complex for plants designed to reduce stress.

Sensi Cal Mg Mix Grow adds the vitally important Calcium and Magnesium, which help to grow robust, crisp vegetables (as well as salad greens). This is a proven recipe, we’ve been using it on our Boston Lettuce for a long time, and it always results in healthier produce.

Relatively low light levels for the pak choi might be 200 micromoles per square meter, while on sunny days the light level may be increased to 400 micromoles per square meter. The bank of 55 600W Metal Halide lights will be automatically adjusted to compensate for these levels by the computer system. There are also shading mechanisms built into the roof of the greenhouse to reduce the impact of sunlight, when necessary.

From Day 29 to Day 34 the plants continue to add weight and on Day 35 (from the time of seed germination) they will be harvested.

Since these greenhouses are larger than our original one, we had to hire extra staff. Instead of two full timers, plus two part timers, each new facility requires four full timers to run it properly, not counting Chuck and myself.

posted by silvio @ 9:47 PM   0 comments


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