marijuana horticulture book

The Second Crop

Marijuana Horticulture

by Jorge Cervantes

This was a time of change and serious improvement. Over the past three months, Nigel and Terry had visited the local hydro store on many occasions and had struck up a friendship with one of the owners who worked there. He had given them heaps of useful advice, and the boys realized that without his input, the first crop could have been easily ended in failure.

The Store owner (we’ll call him Bob) offered to help the boys design their new double sized room, provided they purchase all their new equipment from him, of course. He insisted that the system they were currently running used too much power, generated too much heat, and was to labor intensive to be successfully doubled in size and maintained by two guys already working full time jobs. As usual, Bob was talking sense, and Nigel and Terry decided it was a safe bet to play it Bob’s way and part with the necessary cash. The total cost of Bob’s proposed improvements weighed in at USD $7552 (Eur $6000). Calculating at a rate of Eur $2200/kilo, the first crop paid for itself and more than half expenses of the proposed expansion and improvements. Cool!

Bob’s plan was to: 1 – Double the length of the existing two benches and line the walls of the other half of the storage area with white laminated wood; 2 – Set up an automatic watering system with a large reservoirs to reduce manual labor; 3 – Plant double the amount of clones per area to reduce time in vegetation by a week; 4 – To achieve adequate air flow, install a new 500 cu/hr fan for air extraction, and use the existing 3200 cu/hr for air intake; 5 – Make use of current advancements in reflector technology to decrease the number of lights required from 20 to 14 and consequently reduce the power usage for heat generation by the same ration; 6 – Bob also suggested ditching the pot idea in favor of cocopeat slabs. “Just supply the plants with a top quality organic nutrient, and the garden will be state of the art and organic.”

The room was setup pretty much as Bob had planned. Five Danish made plastic 6 foot 6 inch x 3 foot 3 inch trays were loaded up with coco mats and placed on each 33 foot long bench top. Each tray was installed with a 3-degree tilt to promote drainage. An elaborate systems of drippers and drainage pipes was constructed and each bench was run as a separate entity with its own 400 liter reservoir and 6000 L/hr pump. Both pumps were timed to run x times a day for y minutes, and nutrient runoff was pumped out of the grow room and into the shower drain.

The fans were installed placing the 5000 cu/hr fan high at one end of the room and the 3200 cu/hr fan down low at the other. The 5000 removed air via the vent in the upper central part of the room. The vent was box shaped and permanently connected to a carbon filter. When the filter was not required, a cover on the underside of the box was removed, and air was drawn out through the exposed opening. The 3200 forced cool air through ductwork that ran along the floor under each bench. This air entered the room in four places under each bench, equally spaced along their length. Four pedestal fans were used to mix the air and push it in the general direction of the outlet vent.

The room was lit using fourteen 600-watt lamps, each covering an area of 4 feet 8 inches x 3 feet 11 inches. This was achieved by using high tech adjustable double parabolic reflectors (Adjust-a-Wings). These flexible “wings” were highly reflective and could spread light evenly and broadly at a range of heights above the plants. They were rated to cover areas of 4 feet 11 inches x 4 feet 1 inch and above with 600-watt lamps, so 4 feet 8 inches x 3 feet 11 inches was within prescribed limits. Another lighting product was used in conjunction with the wings and referred to as a Super Spreader. These fit below the lamp and spread excess light and heat from that hot area across the light’s entire footprint. They allow lamps to be close to plants to produce rapid growth but keep growth rate and plant size even.

When compared to the first, this crop almost seemed to grow itself! The irrigation system alone (reservoir size, how many days reserve, nutrient dosing, the coco/Danish tray/run to waste system) saved Nigel and Terry about two hours a day.

The ventilation design combined well with the simple, effective lighting strategy. Air was pumped in and pushed up from below, cooling plants and lights on its way up. The heated air would rise naturally, be trapped by the ceiling, sucked towards the vent/filter, and exhausted from the room. With a small amount of adjustment, the air temperature could be maintained at 80-82F even when the plants formed a dense mass across the whole room.

The wing reflectors could be adjusted to provide even lighting when they were close to the plants (growth and flowering phases) and when they were farther away (early vegetative and final maturation phases). When reflectors were hung low over the plants, the spreaders dealt with any hot spots and insured even lighting.

Nigel and Terry’s second crop grew vigorously and evenly all the way through to maturity. They had a small problem early on with spider mites. Seems the clones they bought had a few mites on board. The mites were dealt with organically and effectively. Bob had suggested the boys use Ecolizer organic nutrients and follow their program exactly. The program suggested misting clones regularly with their “Bugs Away” foliar feed. This solution contains nutrition plus essential oils that coat mite eggs and suffocate them. No chemicals and it worked!

After a total of nine weeks growing, the room was filled with plants that formed a dense layer of evenly developed, dense, sticky, fat bud. The room resembled a “sea of green” rather than a collection of plants of assorted size and shape. As they harvested, Nigel and Terry joked about mowing down a mass of sticky green corn cobs. Cutting, hanging, drying, and particularly manicuring this much weed was one hell of a job and took them a month to finish. The final yield was 12.5 kilos (27.5 pounds) and the quality was A++.

At this point, the boys had covered all their expenses, they were almost half way into their third crop (which was growing strong), and were already 10 kilos in the black. This had been an ambitious project. Nigel and Terry had not achieved success without significant risk and a lot of hard work! Guess who was planning a well deserved “holiday in da sun”?

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