Ed Rosenthal is recognized worldwide as a leading authority on marijuana. In his 30 plus years as America's "guru of ganja" he has written or edited more than a dozen books about marijuana cultivation and social policy that cumulatively have sold over one million. His first book, Marijuana Grower's Guide, is the only title on marijuana cultivation to be reviewed by The New York Times Book Review. After almost two decades, his Ask Ed advice column continues to answer questions on all matters of marijuana from readers around the world.


SMOKING BLUNTS
I attended a meeting that you spoke at. You advised people not to smoke blunts because they were made with tobacco, which you reminded us, is harmful and carcinogenic, unlike weed. The reason why many people, myself included, prefer blunts is because we feel an extra high from it. This is the same as smoking a cigarette after a joint or mixing hash or marijuana with tobacco. Is there any scientific theory as to why this happens, if it happens at all?
Shauw
The rush people feel from smoking tobacco is caused primarily by nicotine. Anyone who has smoked tobacco is familiar with the rush that comes after inhaling: nicotine triggers a cascade of signals in the brain resulting in lightheadedness, dizziness and a relaxing feeling. This is more pronounced in people who are not regular users and who have not developed a nicotine tolerance.
When the two sensations from marijuana and tobacco are combined, it produces a unique high that is both stimulating and mind expanding, although less focused than marijuana used alone.
My opinion is that the high is not worth the serious health consequences of using tobacco. You are all familiar with the statistics-500,000 deaths per year from lung cancer and heart attacks; poor health; premature aging; decreased sexual drive.
Nicotine is highly addictive and causes craving and discomfort when tobacco users refrain from use. However, nicotine in itself is not that injurious. The harmful substances are the tars, which are found in the carrier. You can get the nicotine high without subjecting yourself to as many risks by wearing a nicotine patch or chewing nicotine gum. Of course, this isn't as attractive as a blunt. But that is why blunts can be insidious: they introduce people to tobacco use and leave them with a mild addiction. Often people aren't conscious of their craving, but they are left susceptible to the next step, which is using tobacco without marijuana.

LONG FLOWERING SATIVA
I am planning to grow a long flowering (landrace) sativa. Should I try to mimic its original environment or will it adapt well to normal methods of indoor gardening?
Sativa Lover
Equatorial indicas need lots of light, space and time. For these reasons they are not popular with indoor growers or with high latitude outdoor growers.
The intensity of sunlight declines as you move from the equator to higher latitudes. The reason is that the sun hits the equator at a direct perpendicular angle. As you move away the sun's angle becomes more oblique, and less light falls on a particular area. Landraces from equatorial areas have adapted genetically to the intense sun. To grow well, they need more intense light than most indoor plants receive. Typically, gardeners use a 1000-watt HPS lamp over a 1.2m x 1.2m. space, 1.44 m2, with an input of about 60 watts per square foot. With the indicas, increase the light to a 1000-watt lamp over a 9m x 9m space, 0.81 m2.
Most of the equatorial plants are fast growing and have large stem spaces (internodes) between the leaves, where the side branches meet the main stem. They are not the tight hybrids that gardeners are accustomed to, but their wilder cousins that they have adapted to an environment where they must gain height and canopy space quickly to survive. 1ndicas, on the other hand, adapted to a far less habitable environment. They didn't need height; they just had to tough out uncertain weather and drought, short summers and poor soil. A compact thick-leaved plant is better equipped for the windy Himalayan foothills than a tall lanky one.
Provide each plant twice to four times the space that you give indicas. You can control height somewhat with pruning, bending and super-budding. Still, these are going to be tall plants. Treating them at the end of the day with a strong blue light (5000 Kelvin or higher, daylight or actinic blue) may control the height a bit. The lights should go on shortly before the other lights are turned off and stay on for ten minutes or so. A pure red light such as from LEDs may also control height a bit. A combination of the two may be stronger than one alone. The light should be moveable so the light is "sprayed" all over the plants and reaches most tissue.
Placing fans in the room to create a strong draft that affects the leaves and stems results in shorter, stouter stems and branches. You can also shake the plants to the point where the stems bend, but not to the point that they are liable to break. This also results in shorter, stouter stems.
Time waits for no one, but you must wait for sativas. They often ripen in November, December or January and have a 10 to 16 week ripening time. Unfortunately, they don't do well in freezing weather or under snow. 1ndoors, they should never receive more than 12 hours of light. Ripening is hastened a bit by lowering the light duration to 10 hours as soon as the plants germinate. Even when flowering, young sativas also continue to grow vegetatively.
Outdoors, the plants are well suited for the southern tier of the U.S. One of the best strategies for growing these plants is to start them outdoors in September in an area where plants can be grown in winter. The short days induce flowering and keep the plants relatively short.

NATURE OR NURTURE
Are cannabinoidprofiles and correspondingproportions dependent on merely genotype or does the growing environment significantly influence them?
Magic B
The genetic code determines an organism's potential to grow.
The environment determines how that potential is acted upon.
Think of the genetic code as a set of plans and alternative plans that direct the plant's life processes. 1t holds the information that the plant needs to grow. For instance, if the plant is shaded, it senses the lack of light and produces hormones (gibberellins) that induce the stem to grow taller so it can reach the light.
The potential of a plant to produce THC and terpines is affected tremendously by the environment. First, total production of cannabinoids is dependent on growth since a large plant produces more THC than a small one even if they are of equal potency. Thus growing a large healthy plant utilizing intense light and plentiful fertilizers increases total THC production.
Plants grown under intense light produce a higher percentage of THC than those grown under dimmer lights. High intensity light increases both growth and potency. 1n high quality plants the percentage of THC also increases as the amount of UV-B light increases.
Nutrients also affect the quality of the high. 1n an experiment of fertilizers in 2000, clones produced vastly different quantities of bud depending on the fertilizer that was used. The buds looked different too, and each produced subtly different odors. You can view details of this experiment at http://blog.myspace. com/askedrosenthal.

BRONZE, CHLOROTIC LEAVES
All of my plants are having a problem that I cannot identify. As soon as I transplant and force the girls to flower with 12 -12lighting, the veins of the leaves turn bronze, the leaves are chlorotic, dried out and curl downwards. Then they shrivel up and die. I have treated them for spider mites, potassium and magnesium deficiencies. Then I leached them. I also replaced my entire lighting and ventilation system. The problem continues to decimate my babies.
Betty
Your plants are suffering from copper deficiency. The medium you are using lacks copper so you will have to add it. Copper sulfate, sold as a fungicide, can be sprayed on the leaves and will solve the immediate problem. Copper sulfate or chelated copper can also be added to the planting mix or the irrigation water. This will prevent future deficiencies.


HOT LIGHTS COOL NIGHTS
I am running eight i000-watt HPS air-cooled lamps hooked up to a33 cm exhaust fan. Even so, the room is getting too hot. Sometimes it reaches 30 C. The room is 4.6m x 2.7m. I live near the beach where it staysfairly cool days and go into the 4 to 10 degrees C most nights.
Rick Banana
There are two solutions to the heat problem. The first is to run the lights in the evening, when the outside air is cool. Cool the room by venting in outside air and removing the hot air. The incoming air should be filtered to keep insects from blowing in. The outgoing air should be deodorized using a carbon filter, negative ion generator, ozone generator and/or electrostatic precipitator.
Another solution is to cool the air inside the room with a window air conditioner. Rather than exchanging air and dealing with odor, the room is vented infrequently. When using this solution, CO2 enrichment is required.


CALCULATING WATTAGE
I am trying to decide what kind and how much light to use in my grow space. I'm trying to decide between compact fluorescents, Metal Halides and High Pressure Sodium lamps. Do you use the actual watts used or the light output?
Buddy
High pressure sodium lamps are the most efficient lamps available that are generally regarded as reliable for flowering. They emit 30% or more light per watt than fluorescents. However, with high wattage fluorescents you can get the light closer and they may have spectrum advantages, delivering more useable light to the plants than HPS lamps.
A 1000-watt HPS lamp, which is often used to cover a 1.2m x 1.2m, 1.5 m2, uses about 60 watts per square foot and delivers a total of 130,000 lumens, or 104,000 lumens per square meter. Most modern varieties do well under 60 watts of light input per square foot. Listed below is light output information for Metal Halide Lamps, which produce a white light, High Pressure Sodium Lamps, Compact Fluorescent lamps, T5 Fluorescent Stick Tubes and T8 Fluorescent Stick Tubes (standard fluorescents).
The light here has been calculated as lumens, which relates in part to how the human eye sees light. A more accurate measure would be PAR Light, which stands for Photosynthetically Active Radiation, which measures the energy that light contributes to photosynthesis. The chloroplasts, the organelles, where photosynthesis takes place, are most efficient at converting red and blue light to useful energy. 1t is much less efficient with orange yellow, yellow, and green light. As a result, some fluorescents may produce a higher percentage of output in useful spectrums.
Recently 1 came across a fluorescent tube that may be especially useful for cultivation. 1t is the F32T8/Market Lite Plus - 4 ft. - 32 Watt - T8 Linear Fluorescent Tube made by-1nterlectric Corporation. 1t was designed to enhance the color of meat in display cases. 1t highlights red and blue spectrums, which makes it beneficial for plants as well.

400 IN 1000
I am working on a small indoor hydro system andhave been gathering suppliesfrom swap meets and garage sales. I bought ai000w MH ballast from a garage sale, but since it is a smallgarden I want to use 400w MHlamps. Can I use the i000w ballast to power the 400w lamp? What will happen?
Gonzo
1t is not a wise idea to use a 400-watt lamp with a 1000-watt ballast. The bulb will blow out and be unusable. 1t may explode.
A 1000-watt lamp adequately covers 16 square feet, a 400-watt lamp only about 6 square feet.

BOOSTING COa
I have seen ads for the CO2 Boost Bucket & Pump. The cost ofa CO2 monitor and regulator system is prohibitive to me right now. Do you have any advice regarding this alternative CO2 enhancement system?
Phantom Rebel
The Boost consists of a covered bucket and air pump. The bucket is filled with organic matter and hyperactive micro-organisms. The air pump delivers oxygen to the organisms, helping them metabolize faster and produce more CO2. The pump also creates an airflow containing the CO2 enriched air. The organic mix provides CO2 fuel for about three months. 1t is easily discarded or, since it is digested compost, it can be used in the garden or in a planting mix. A replacement mix bag is inserted into the unit, and it is ready to continue creating CO2.
The pump may very well be the solution for a closet garden. 1t produces enough CO2 to raise atmospheric levels significantly. 1t is a no muss, no fuss system. The one negative aspect to the unit is that it emits CO2 constantly. Plants do not use CO2 during the dark period, only when photosynthesizing—during the light period. Perhaps turning off the air pump along with the lights would decrease CO2 production during the dark period.

CLONE COLLECTION
I am growing outdoors in the wilderness. It is a four-hour trip from garden to bivouac. When I trim my plants before they flower, how long do I have to get the clone branches into the rooting medium? How should I handle them so they don't expire in the heat?
Luigi
Cuttings do not have to be set for clones immediately; with proper care they can be preserved for several weeks. The requirements for keeping the cuts healthy are to make sure they remain cool and moist so they don't dry out.
You can accomplish this fairly easily by wrapping them in wet newspaper, then placing them in a plastic bag. Put this into a container such as a cooler or a paper bag placed in a cool space such as the passenger compartment of a car.
Cuttings can be stored for a minimum of a week in the moistened plastic bag in a refrigerator's fruit/vegetable compartment. They should be kept at high humidity.


CO2 AND T5HO FLUORESCENTS
I recently started using T5HO lighting in my veg room. I am using all blue bulbs for veg. The lights are densely packed above the canopy and I have been able to achieve about43 wattspersquarefoot input, emitting about 4000 lumens per square foot. I am enriching the environment with Co2 using a tank and a Sentinel controller. I keep the level at 1500 PPM. Do the T5'sprovide enough light intensity for the Co2 enrichment to be effective? Will CO2 enrichment be effective in increasingplantgrowth using my currentlightingsetup?
Doug
Yes. CO2 enrichment will result in a dramatic change in growth rate under CFL lights. The plants have enough light to photosynthesize faster when the air is enriched. The result is that more sugars are needed for the growth used to produce larger plants.
Enrich the air to 1500 parts per million (PPM) during the lighted period. Cannabis doesn't use CO2 during the dark period, when it is not photosynthesizing.

CLONING SOLUTION
I was following the instructions in one of the Easy Marijuana Gardening. It says to dip cuttings in a cloning solution. When I askedfor a cloning solution at the local garden store, I was given Rootone rooting hormone with fungicide. It is a powder, not a liquid, is that okay? The directions also say that when placed in the rooting medium to be sure that one node is covered—do I need to do that with marijuana?
Robert
You could use Rootone but the liquid gels and other newer solutions are more effective and easier to use. 1f they aren't available locally, you can find them on the 1nternet. 1t is a good idea to cover at least one node with rooting solution because the plant absorbs more hormones through the fresh wound.

FERTILIZING CLONES
We transplanted clones in rock wool to Black Gold (R), an enriched planting mix, two weeks ago. The new growth ispale green-yellow. Should we befertilizing with the recommended dosages or beginning with 1/4 of the recommended solution? We just bought Humboldt Nutrients' Grow (3-1-2) and Micro (5-0-1). Is this a goodformula for the plants?
Lanie
The plants need a lot of nutrients because they are now in a fast growing vegetative stage. They should receive full strength vegetative-cycle fertilizer as directed on the label.
The fertilizers you picked up are slightly out of balance because they contain little phosphorous (P), the middle number referred to on fertilizer labels. That nutrient is usually found in abundance in the flowering formula. The Humboldt kit is a three-part mix and you are missing one component.