Jorge Cervantes

There are as many ways to grow marijuana as there are people who grow it. Not all new-fangled gizmos are worth their weight in bud, but the educated consumer can definitely increase harvest size with the right system.
Looking at the hydroponic innovations of the last few years, we see a menagerie of new gardens, meters and nutrient-delivery systems. Often these products are poorly thought out; beta models are sold to unsuspecting guinea-pig growers with the promise of immense yields and knock-your-socks-off performance. Too often, the real underlying goal is to make something different than the competition and ensure that the product has a high profit margin.

Every time a grower sees a new product, they must ask: What is the goal of those applying this high-powered technology? Does this new high-tech innovation actually increase yield? Are these products introduced to stroke my ego and line the pockets of manufacturers with the proceeds of green gold? Or are they launched to increase yield and improve the plight of growers? Are the purveyors of products able to show you real, visible proof behind their promotion? You must be skeptical and ask yourself these questions each time you see a new "high-tech" hydroponic product.

"Follow the trailing edge of technology" was the sage advice given me by one of my mentors, Sebastian Orfali. The leading edge of technology is often an equation for innovation with failure as the common denominator, hardly of interest to a grower with production in mind. But, put the tried and true principles of technology to work, and harvest heavy!

Over the past 20 years I have seen several gardens that used vertical space with promising results. Plants in small pots were placed on shelves around the perimeter of the garden to take advantage of wasted light, or a bare high-intensity discharge lamp would hang down among plants, or gardens would be tiered and lamps without reflectors would hang among plants. But these vertical principles were just starting to be exploited.

The innovative Cage is the first garden to combine hydroponics with lighting and vertical space to maximum benefit. The inventive garden stacks clones at a 45-degree angle in irrigated vertical columns around HID bulbs. The bulbs need no reflector, and all light plants receive is direct!

Technology is the application of science. When a grower finds a way to use all the light from a bulb by building the garden around the lamp, it is a major change in technology. Although simple, this shift allows growers to plant more clones that receive more light. The technology also lets hot air flow freely away from bulbs, because no reflector is in the way to act as a heat collector; bulbs burn cooler and heat is easier to evacuate.

The garden uses high-tech principles combined with simple pragmatic forces of nature to benefit growers. Direct, unreflected light from the bulb travels a short distance to illuminate plants and must penetrate a shallow mass of foliage only 6-8 inches deep. The bright, intense light reaches more buds in this vertical garden than with conventional horizontal gardens.

The principles of this high-tech garden are sound and compliment one another, but how do you grow in it? What is different about growing vertically?

HYDRO TEK [cont.]

I interviewed several growers using this system, but only one, Doc D., would show me his garden. I was fortunate to see his grow show, because he keeps his rooms spotless. This is the main reason that he has had but one brush with bad bugs. When he was growing in soil, the thrips moved in, laying eggs in the substrate. After he purged the soil and changed to rockwool blocks, the thrips left, never to return.

"I like this high-tech system, but I'm still learning how to grow in it," says Doc D., passing me half of a smoldering joint. "The problem I have is to keep plants growing consistently, so they max out their weight at harvest. This is a skill, and I am getting better with every crop,"

Four HIDs, two 400w high-pressure sodium and two 400w metal-halide lamps, illuminate the garden. They are stacked one on top of the other, in line, in the center of the garden. Bulbs are alternated between MH and HPS to give a complete spectrum for plant development. One grower I interviewed substituted 250w lamps and harvested almost as much as with 400w lamps.

Big 180-liter (50-gallon) reservoirs supply each garden with nutrient solution in this run-to-waste system. The solution is pumped into feeder hoses every three hours for 20-second stints. Each garden gets about 4 liters (just over a gallon) of nutrient solution with each irrigation. A total of 18 liters are used daily. The delivery system is simple and maintenance-free. A 0.06-mill grommet hole is punched into a 0.5-inch supply tube. The hole is large enough to let any debris pass through, but small enough to create a spray. Given the vertical orientation and number of distribution sites, nutrient solution always cascades over roots.

Doc D. takes cuttings and roots them in rockwool cubes for about 2 1/2 weeks. He grows them long enough so they have a chance to develop strong healthy roots, before transplanting them to a small ebb-and-flow system.

"I start the plants in a little net pot inside a cup on a flood-and-drain table," he explains. "When the roots have grown out of the net pot and circled around the inside of the cup, they are big enough to put into the columns. The roots have to hang down in the columns, so the nutrient solution reaches them and keeps them wet. If you don't plant them with a big root mass, you will have to hand-water from the top of the pot. It's difficult to water the pots, because they are stuck in on a 45-degree angle."

Clones are grown in the vegetative cycle under 18 hours of light on the flood-and-drain table until they are about 8" tall. They are transplanted into six planting sites on each of 12 columns (72 total plants) in the vertical garden, and given 18 hours of light for 4-5 days, before flowering is induced with an even 12/12 day/night light-cycle. Within a couple of weeks, the short plants elongate another 8".

Doc D. had a little trouble keeping nutrient-solution EC (electrical conductivity, or overall nutrient concentration) on an even keel. His problems were easy to solve, though, because the nutrient solution runs to waste and is used only once. He would check the EC daily, and add plain water or diluted nutrient solution to bring it into the desired range.

At planting, he starts with an EC of 7 and moves it up to 13 in 4-5 days. He keeps it between 11 and 15 until harvest. He maintains the pH in a range from 5 to 5.2; if it's any higher, nutrient deficiency problems start to crop up. Every day, the pH drifts up about 0.2 points. He meters the solution daily and adds pH Down to compensate. He fertilizes with GGold, a two-part mix that is easy to use, complete and gives good results. He pumps the runoff nutrient solution outdoors, for application on the soil garden--where his strawberries are the biggest and best on the block. Every week, he flushes each garden with Clearing Solution that he keeps in a smaller reservoir.

"Even though this garden is high-tech, it has taken me a few crops to iron out many of the wrinkles and increase production." says Doc D. "The biggest problem I have had to conquer is keeping plants growing the same size all the time. If one plant gets too big, it shades the others."

One thing he did not anticipate was how the dynamics of the room change when growing in single or multiple vertical enclosed gardens. A warmer microclimate forms within the garden, and the perimeter around the garden is a little cooler. When the gardens are not filled with plants, light escapes, heating the walls and floor, which warms the entire room earlier in the day, and it stays warmer longer. When the Cage is full of plants, the heat tends to stay within the core garden area. The surrounding area is slower to warm, and cools faster at night.

Once Doc D. understood those dynamics, he placed a circulation fan in the center of the garden, below the lights. CO2 from a tank is metered and transported via tubes to the center of the garden, just under the bulbs. The colorless, odorless gas is directed upward by a small fan. The fan serves to disperse the CO2 and evacuate heat from the lamps.

Following the trailing edge of technology reaps vast rewards when applied properly. For example, this grower uses two simple controllers attached to a vent fan to regulate humidity and temperature in the room. He could use the top-of-the-line Green Air atmospheric controller (, but his needs do not require this level of technology. A humidistat turns the in-line extraction fan on when the humidity climbs to 65% and goes off when it reaches 52%. The fan is also hooked to a thermostat that controls room temperature. When the temperature climbs to 85°F, the air is evacuated.

The humidity climbs to above 70% for about 15 minutes just after the lights go off. A timed vent-fan cycle that starts just before lights out and continues for 20 minutes afterward would keep humidity at bay, but no noticeable problems have been caused by the excess humidity.

The room temperature starts at 70° in the morning and climbs to 85° by the last three hours before lights out. When packed with plants in full bloom, the temperature inside the garden rises sooner than if it were empty. Doc D. is contemplating placing a larger fan in the center of the garden to keep temperatures more consistent.

Marijuana-growing is so common in British Columbia's Lower Mainland, which includes Vancouver and the surrounding communities, that the telltale smell of ozone escaping from a home alerts onlookers to the grow show stashed inside. "I always make a sniff test outside. The RCMP [Royal Canadian Mounted Police] are not idiots! They know what ozone smells like and what it's used for!" advises Doc D.

You would think that this high-tech grower would use some electronic gizmo to remove all traces of odor from the room, but not so. His choice is the old reliable, tried and true activated-charcoal filter ( The large, heavy unit can either stand on the floor or hang from sturdy fasteners anchored in the ceiling. Air first passes through a pre-filter that retains heavy airborne particles (dust) before it enters the activated-charcoal chamber. The activated charcoal absorbs virtually all of the fragrant molecules or ions, discharging clean, fresh air to the outside. As long as the humidity stays below 70% and temperature below 80°, there is no excess moisture to clog carbon filters. After about 12 months of constant use, the carbon runs out of absorption capacity and must be replaced.

"My biggest fear was the water hitting the lights," explains Doc D. "One night I smoked out and looked at the garden, and it dawned on me the lights are surrounded by nutrient solution. I thought something is going to spring a leak, water will hit one of those hot bulbs and kaboom! The thing is going to explode! But there has not been even one little problem at all. The lights stay cool and an occasional drop of water has not caused any trouble.

"I'll tell you another weird thing about this garden," he continues. "The light is coming from the side, but the plants continue to grow upward. I always thought plants would grow toward the light. I'm not sure why this happens, I just know that it happens, and you can use this information to grow more nugs!

"It's hard to say exactly what I have been doing to become a better grower. I think it is all the little things that I have learned. Every crop continues to weigh in heavier. My first crop weighed two pounds. That's almost a half an ounce per plant. My second harvest was 2.25 pounds, third 2.5, fourth 2.7 pounds, and now I'm harvesting 3 pounds. [0.66 ounces per plant.] That's a 33 percent increase in yield over the first crop. I think I can get up to four pounds or more per crop with a little more experience."

A 3-pound (1,362 grams) harvest after 45 days of flowering weighs in at 0.63 grams per watt every 30 days. That's a strong harvest, and definitely above the benchmark of 0.5 GPW every 30 days.

There is all kinds of light wasted in most gardens. With a little bit of thought and construction, you can fill these bright spots and increase your harvest weight substantially. Remember, follow the trailing edge of technology!

To learn more about the Cage and several other innovative gardens, check out the message boards on these Websites:, and