Indoor Marijuana Horticulture by Jorge Cervantes

Marijuana Grower's Handbook Indoor Greenhouse Edition by Ed Rosenthal

These two books are probably among the best all-around grow books dealing with high technology. Of course, there have been several articles and books dealing with specific subject areas which are far superior; but these two books attempt to put it all together for the indoor grower. Yet, I was disappointed with their overall performance.

IMH is longer, but has more factual errors. Examples from IMH:

  • page 32 states that red is one of the two most important light colors for plant growth, and that red is 650 nm. However, the peak plant response occurs at 675 nm, not 650 nm. Also, plants can use the entire spectrum efficiently, from 400-700 nm, not just red and blue. See Mc- Cree(1972). Cervantes appears to be basing his conclusions on outdated sales literature.

  • page 40: “The hoods may be made of sheet metal, polished or painted aluminum, or polished stainless steel. The color is usually flat white, but some companies paint them glossy white.” On the contrary, most white hoods are glossy, which as Cervantes states is less reflective than flat white. Glossy white is more usual than flat white because of consumer ignorance. Shiny aluminum makes for a more efficient reflective surface compared to white because it is more specular; i.e., it reflects at exact angles like a mirror. A diffused reflective surface such as white paint would bounce the light around inside the reflector, losing energy to heat.

  • “Sheet metal” is not really a specific kind of metal, but rather means a particular shape. Many different kinds of metal comes in sheets. Stainless steel is heavy and not very reflective.

  • Paraboloid hoods, with many triangular facets, are vastly more efficient and will pay for themselves many times over.

  • page 44: Cervantes recommends LPS for side lighting. However, this would result in dark corners. Also, LPS is monochromatic in the yellow, which is less favorable a spectrum for plant growth than UHPS. Lumens is a measurement of what the human eye sees, which is a bell- shaped curve centered at green. Plants prefer orange/red.

  • page 50: “Ballast kits may be ordered from Dansco, G.E., Sylvania,Universal or Westinghouse.” However, of that group, only G.E. and Universal manufacture ballasts, and they do not sell direct to the public or to retail stores. Also, contrary to what Cervantes states, Jefferson is not the quietest transformer on the market. Sola and G.E. are at least as good, and Advance is about equal, to Jefferson.

  • page 50: “Ballasts are manufactured with a protective metal box. This outer shell safely contains the core, capacitor, and wiring.” Ballast manufacturers do not usually provide a metal box, this is done by the fixture manufacturer (i.e., halide shop). The transformer includes a core and coil, not just a core. The core is not electrically live and should not be covered. Exposing the core increases ventilation, which decreases heat and resistance, so there will be more energy going to the bulb. Also, it is heat which bakes the resins, causing air gaps in the laminations, which rattle.

  • page 54: Cervantes claims that clear halides are the most commonly used, the brightest, and the best spectrum. Wrong on all counts. See Farmer In the Sky (FITS) Vol.4 #4.

  • page 71-73: This safety section is incomplete. See FITS, Vol.4#4.

  • page 90: Dolomite lime does not have a neutral pH. It is slow- release alkaline.

  • page 92: To use either Potassium Hydroxide or Sodium Hydroxide for pH control is not a good idea. See FITS, Vol. 5 #2.

  • page 94: It is risky to use mushroom compost. You stand an excellent chance of growing mushrooms and fungus, which compete with the plants.

  • page 108: A cubic foot equals 7.48 gallons, not 6 gallons. See Page’s Pages, p. 6, by Professor G.L. Page.

  • page 110: Calcium and Magnesium are referred to here as micronutrients. However, they are secondary nutrients.

  • page 116: Epsom salts, or magnesium sulfate, is recommended here in case of magnesium deficiency. However, Magnesium Oxide is much better. Magnesium sulfate contains more sulphur than magnesium; sulphur is a tertiary nutrient, while magnesium is a secondary nutrient.

  • pages 142-144: This section on hydroponics is vague and ignores the most common system.

  • page 151: 100 degrees F. is too high, even with C02. Plant quality • decreases with high temperatures (see the original Ed Rosenthal book, deluxe edition).

  • pages 152-153: His remarks concerning temperature seem to be off-base. See Bill Drake (1969).

Let’s now consider the new Ed Rosenthal book. There is not a whole lot of new material in this book, and most of the references are from the 1970s. The best section is the one on hydroponics, although he does not cover all the systems currently available.

  • His most serious error occurs on page 73: ‘‘Good heaters burn cleanly and completely, leaving no residues, creating no carbon monoxide (a colorless, odorless, poisonous gas).” No generator can be perfectly adjusted, and carbon monoxide will be produced. Without adequate ventilation, the oxygen will be depleted, producing even more carbon monoxide. Combustion systems also produce harmful heat and moisture.

  • Rosenthal’s section on pH repeats most of the common myths. See FITS, Vol. 5 # 2, and Vol.4 #3.

  • Using chicken wire and aluminum foil as Rosenthal recommends would not make a very good reflector. For one thing, foil creates hot spots.

  • Page 65 claims that halide and HPS lights use the same reflector; he neglects to point out that the HPS requires a 5KV pulse-rated socket. On the same page, the claim is made that HPS can be used as the sole source of light. However, most varieties require some blue light at all stages. This can be obtained by using halide and HPS light in combination.

  • On page 66, Rosenthal claims that LPS emits in a narrow band at orange. However, this light is much closer to yellow.

If I were a professor of indoor high-tech growing, I would rate IMH as a C-, and MGH as a C .


Some growers have the problem of what to do with their profits. If too much ‘‘underground” money surfaces in a manner which leaves a paper trail, the IRS could get you even if the narcs are foiled. Banks routinely microfilm all checks; and the feds can force disclosure of these records. Much the same can be said of stocks and most investments. I wouldn’t trust banks or commercial warehouses. Banks are controlled by government, and commercial warehouses can be raided by government. Bearer bonds issued by local governments are usually tax-exempt and anonymous. However, I think government bond investments are morally questionable. They can also be risky; if governments default, what do you repossess?

The single family dwelling is ordinarily an excellent investment. However, if you get busted for growing something illegal in your house or on your real estate, government agents may attempt to confiscate your house and property. Of course, the possibility of detection can be minimized by using electrical generators in an underground shelter. Also, air cleaners are useful for smell and pollution control.

An investment in better equipment, C02, and hydroponics, can increase production without significantly increasing the electrical bill. Gold and silver coins are an excellent investment from a survival viewpoint. You probably won’t make a quick killing, but precious metals are a good conservative investment because they are always worth something. They have been used as a storage of value for thousands of years. Of course, long term storage of food is the most conservative investment. If you have any money left after taking care of your basic and security needs, a trip to Holland can be a good investment!


UHPS or ultra-high pressure sodium is a term I coined to describe a color-corrected high pressure sodium light. This relatively new light is designated by the suffix “DX”. It is only made in 250 watts, by General Electric. The color corrected Optimarc uses a different technology and has a different spectrum which is not as desirable for horticulture; it has an even distribution across the spectrum with a spike in the green. The DX bulbs have more in the favorable orange/red spectrum; however, they must be supplemented with blue light. For most plant species, a deficiency of blue causes stem elongation.

Round reflectors are the most efficient, because a pyramid would bounce the light back and forth in the corners of the hood. However, most rooms are square; which means the corners are the most light deprived. Therefore, a 250 watt UHPS in each corner makes sense. As the plants get taller and approach the budding stage, side lighting can provided from the corners. This allows for more light on bottom leaves, more red at budding, and efficient utilization of the entire room space.

In a typical 10’x 10’ room, I recommend a 1000 watt phosphor halide with 7’ hood in the middle, and four 250 watt UHPS lights in the corners. Start out with the halide alone, and add UHPS when there is at least 3/4’ between the top of the soil and the bottom of the reflector. This means that peak power consumption is only 2000 watt.

It is better to utilize light most efficiently, one reason being that less heat is produced, particularly useful for minimizing ventilation and supplemental C02 loss.

Another relatively new light is the Sylvania MS400 3K. Different phosphors are used to achieve a different spectrum, with more in the horticulturallybeneficial orange/red. The color temperature of this bulb is 3200 Kelvin, which also happens to be excellent for video tape recording.

Unfortunately, a 1000 watt version of the 3K is not currently available. If there is enough demand, perhaps Sylvania will develop such a bulb, and bring it into production. The 3K bulb was tested a couple of years ago by Dr. R.A. Norton, Superintendent and Horticulturist, Northwestern Washington Research and Extension Unit, Washington State University, Mount Vernon Washington. He compared growth rates under the MS400/C/BU and the MS400/3K/BU. The overall average increase with the 3K was found to be 16.2%. In the photo below, the 3K bulb is designated by an “R”. st



Wolf Segal - Farmer in the Sky

35 Years of Innovation in Large Scale Cannabis Cultivation & Inventor of the Sea of Green method.

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