Ask Ed

Stem Borer
My biggest and best plant is in her last two weeks of flowering. I noticed a hole in the main stem about three inches below the bottom of the main cola. It is about a half-inch in diameter and it’s surrounded by a white growth that looks like mold. Upon closer inspection it turned out to be chewed tissue inside from my plant after the insect had burrowed its way in there. What kind of insect would burrow into my plant at that height?

Mill Hall, Pennsylvania

It could be a caterpillar but it might be a beetle. Caterpillars enter the stem to feed and pupate. Beetles enter mostly to lay eggs. In either case they are not good for the plant and will destroy the inside flesh. The creatures can be killed with a pyrethrum solution. Use a syringe to inject the solution into the stem. Clean the hole with hydrogen peroxide and then rub it using a glue stick. The glue seals the wound to air and infection.

Caterpillar on vegetative plant. A single caterpillar can inflict an extraordinary amount of damage on a plant because of its voracious appetite. Caterpillars hanging out on the exterior of the plant, such as this one, can be picked off the plant or can be eradicated safely using Bacillus thurengensis, a very safe biological insecticide made from bacteria. It’s the active ingredient of the insecticide Dipel(R). Caterpillars that have bored into the interior of the stem can be reached using a hypodermic needle.

Immature Plant

I am growing one plant in a container on my balcony. It’s already early fall and I haven’t seen a clear indicator of sex. In the area that I live it is quite common for snow to appear by mid-October. Should I keep my plant outside till it freezes or snows or should I bring it in and start the flowering process inside?

Electric Jesus,
Calgary, Alberta, Canada

The plant that you are growing on your balcony is either a late season plant unsuitable for growing outdoors at your latitude or the flowering is delayed as a result of light pollution. The after-hours light could be coming from a room lamp shining out to the balcony, or from street lighting. Any light interrupting the daily regimen of the dark period delays flowering.

The plant is a female. If it were a male, it would have flowered already since they flower earlier than females and extended light periods don’t affect them as much.

You have three choices. You could try building a small greenhouse on the balcony using plastic wrap or bubble wrap. You could carry the plant back and forth so that during the day, the plant is sunning on the balcony and at night it is in the secure darkness of a closet. If you are going to do this, you must move the plant at a consistent time every day so you don’t throw off its schedule. Finally, you could simply move the plant permanently indoors and flower it under lights.

Low pH

I have just read an article in Cannabis Culture on pH that recommended keeping the pH under 6.0. I grow in Sunshine #4 (peat/perlite) and add two cups of dolomite lime to each bale. I water every 3-5 days with Advanced Nutrients 3-part copycat formula at 700-1200 ppm and a pH of 6.5.

Each time I water, about 10% of the water drains to prevent salt buildup. My yield is 1.5 lbs. per 1000w HPS every 9 weeks. This yield is adequate, but the article indicated that I could produce more with a pH below 6.0. This scares me a bit, but at the same time I am very intrigued! Do you have any thoughts on this? Any idea how much I could affect my yield one way or another by trying this?

Saucy Bastard,

I have read articles and fertilizer instructions that have advised a pH of 6.0 or lower. Every time I have tried it hydroponically, the plants suffered from nutrient imbalances. Using the same nutrients at 6.3-6.6 produced much better results.

You took acidic peat moss’s low pH into account and balanced it by adding alkaline lime. Other plant mediums also have pH levels that affect the root environment. Rockwool has a high pH that needs to be taken into account when irrigating. Starter cubes should be buffered by soaking for a day in low pH water (5.0). Throughout the cycle, rockwool should be irrigated using a solution with a pH of 6.1 or 6.2. This counteracts the alkaline molecules constantly being shed by the rockwool.

Organic planting mediums that use peat moss or wood by-products as a base allow for more latitude in pH levels. The carbonbased molecules in these ingredients interact with the nutrients and hold them temporarily, buffering the environment. In addition they support large colonies of micro-organisms that work in a symbiotic relationship with the roots. The mediums themselves absorb some nutrients temporarily and release them over time. This modifi es the peaks that often cause environmental stress in hydro systems.

Consent to Search

I live in Chicago in a poor minority area and the cops here pull you over and search you for no reason. If they find a bag of weed they take you to jail. Do they have the right to stop me, a pedestrian, because I live in a drug infested neighborhood? Can they charge someone with possession if that person did not consent to a search?

Michael B.,
Chicago, Illinois

The police have the right to approach anyone in public to talk with them. In order to conduct a search, the police must have your consent or probable cause. Then they can search to determine whether a crime has been committed.

Under some circumstances you may be required to identify yourself. You have no further obligation to speak with the police at all.

Do not resist the police if they demand to search you. Obey them but do not consent. Sign no consent form and make it loud and clear that you are not consenting, only obeying police orders.

If the judge follows the law, the search and thus the case will be thrown out. Don’t always count on a fair or logical judge. It’s best if you have witnesses. Notice and try to remember who was around and watching the event so they can be canvassed later.

If these violations of your constitutional rights happen regularly in your neighborhood, contact a civil rights lawyer to look at discrimination aspects of the situation. I’m sure the cops are not messing with young people in Lincoln Park.

CO2-Oxygen Displacement

You recommend CO2 as a boon to plant production when growing under indoor lights at 60-100 watts per square foot. You also mention that CO2 is not good for the root zone as it displaces the needed O2 used by the roots to “burn” the sugars and build the roots. So is there a conflict with upping the CO2 content of a room and promoting healthy root development? Would a supplementary system of oxygen distribution (with tanks) be of benefit in such an instance?


The amount of CO2 found in the air is about 375 parts per million (ppm), or 0.0375%, almost four one hundredths of one percent. A CO2 enriched garden might have a CO2 content of 2000 ppm, or 0.2%. In contrast, oxygen comprises about 21% of air’s volume. In a garden area, where the plants are releasing O2 into the air, the percentage of the gas will be slightly higher. The increased amount of CO2 in the air has little if any effect on the amount of oxygen absorbed from the water.

At the air-water surface, water releases CO2 to the air and picks up oxygen. That is why it’s recommended that reservoirs (and fish tanks) keep the water circulating. The more the water circulates and comes in contact with air, the more it releases CO2 and holds oxygen. Even in a CO2-enriched room, the water releases CO2 in favor of O2.

Growers have sometimes thought of enriching the water with CO2. This is a bad idea because the CO2 will displace some of the O2 making it harder for the roots to absorb enough of it.

Adding O2 to the roots using a tank is not a bad idea. Enriching the water or the soil can only help maintain a healthful environment for the roots. Some research has shown that roots enriched with oxygen are healthier, grow faster and are more efficient at absorbing nutrients.

Marijuana Coffee

Can you put pot in the coffee filter and make a potent drink?

Desperate and Addicted,

You could use the filter method. If you put cannabis in a coffee filter and run hot water over it, some of the THC would mix with the water the way oil mixes with hot water.

A percolator, which circulates hot water through a bowl containing pot, would produce a stronger brew. So would simmering or steeping the cannabis in hot/boiling water and then straining it and drinking it. Coffee or chai made with milk or soy milk would be even more potent. The milks contain lecithin, an emulsifier. Emulsifiers help oils break up into smaller pieces so they mix more evenly and completely with the liquid.

Two double pot chais with soy milk, please!

These clones are growing in Oasis(R) cubes, which are made from a foamed plastic. The cubes are sterile, have a neutral pH and contain no nutrients. Clones do best in these cubes growing at a pH of 6.3.

Mangled Branches

I just moved my grow room to a new location. The longer branches are tangled. The buds are only three weeks into flowering. Should I tie them up to a stake? What should I do?

Snow Bud,

If the tangled branches are allowed to grow together they will shade each other, causing a decrease in yield.

Light is the energy the plant uses to power photosynthesis. So light equals growth, and ultimately yield. Any area of the plant that is not receiving light doesn’t contribute because it isn’t getting power.

To solve the problem, untangle the branches and figure out how to keep them from interfering with each other. Each should have its space in the canopy so that it receives unobstructed light. Lower branches that are constantly shaded or have only small buds should be removed for several reasons. They divert nutrients from the A-quality buds, they are more likely to become infected with fungus or attacked by insects, and they hinder air circulation.

The newly untangled branches can be kept in place using stakes or nets, or by tying branches to an overhead support using a wire or a bin to hold them upright. Whatever method you use, make sure that each bud is kept in its space and no buds are left in the dark.

You might find a light mover is a convenient way to make sure that the light gets to all sections of each bud. As the movers revolve or go back and forth, the angle of light relative to the plants changes. Bud parts that might be in shade under a stationary light get their moment under the “sun.” Since the light is distributed more evenly the plants will grow more uniformly.

Any light that escapes the garden is lost to the plants. Reflective walls and curtains help to bring light to the garden and illuminate the buds. Placing an aluminum foil shade on the reflector to direct straying light back to the garden can help too.

Keeping Clones Alive

How small of a container can I keep clones in for three months? The clones don’t have to grow, they just have to remain alive and healthy so that when my new garden is ready I’ll have new mothers from my trusted selected plants. It would be convenient if I could use 8 oz. Styrofoam cups.


You can keep the clones alive and healthy but growing very slowly so they can remain in 8 ounce containers by limiting all of their inputs. They should be kept in relatively dim light?less than 10 watts of cool-white fluorescent per square foot, or 100 watts per square meter. They should be fed growth cycle formula fertilizer at one-quarter to one-third strength. Finally, the environment should be kept on the cool side, in the low to mid 60s F, 15-18 degrees C.

Careers in Cannabis

I’m trying to find an interesting career. I’d like to get a degree in a field of marijuana research. My goal is to find out what makes marijuana work and to be able to make a living doing it. My school counselors and other adults haven’t offered me much help or guidance. My parents are happy to have me pursue my interests because they think that I am my own individual and that I want to do something legitimate. I don’t know who else to ask, so I’m asking you.

What kind of schooling is there for this and are there many opportunities to get a job? What types of jobs are there and what do they pay? Finally, I live in the Appalachian Mountains and I’d like to stay in this area. What is the possibility of doing independent research for larger companies out of my home?


You have a lot of career choices. Many areas of study including the social and natural sciences have opportunities to study marijuana. Since you are interested in what makes marijuana work, you may be most interested in a career in biochemistry. This might slant in the direction of genetics, molecular biology, neuronal research or similar disciplines. These fields require backgrounds in biology or chemistry at the bachelor’s level followed by advanced degrees in more specific fields.

If you are more interested in the botanical side you would take a botany or chemistry major, and then zero in on your specific field for your graduate degrees.

The field of cannabis research is dominated by PhD’s and you won’t be taken seriously for a research position without one. Commercially, the research is not conducted by individuals, but by teams of researchers working on projects funded either by the government, pharmaceutical or seed companies.

The field is fascinating and is just opening up. Since endo-cannabinoid pathways have been found in various organs as well as in the brain, and because research to date indicates that cannabinoids play key roles in pain, stress relief, food uptake, and immunity, many doctors think marijuana and cannabinoids will increasingly be considered essential medicines.

Hermaphrodite Problem

I have a hydroponic drip system set-up with 2 plants growing in the same reservoir. They are in the third week of flowering. One is a female. The other plant’s lower branches produced male flowers. The upper branches have female flowers. Because my set-up is small, I have been clipping the male flowers as soon as I see them.

I would like to keep my girl pure but I know it’s going to be tough to keep pollen from straying. I can’t move the hermaphrodite. Can I leave them together if I eliminate the male buds as I find them?

Caribe Poet,
Key West, Florida

You mentioned that the hermaphrodite’s upper growth is male-free and that the lower branches are producing male flowers. The solution is simple. Remove the lower branches. By eliminating them, more nutrients will be supplied to the upper branches, spurring their growth.

Sometimes a plant will have a single branch or small group with male flowers. These are easy to find and remove. It’s more difficult when the hermaphroditism is more random and the male flowers hide amidst innocent females.

This plant is ripe but the male flowers haven?t opened yet.

Leaves Wilt During the Day

I am growing some fine, healthy looking plants. Every day when the sun is strongest the leaves on the plants wilt a bit. Then, as the sun fades later in the day they perk up again. The soil is moist so they aren’t too dry. Why do you think they’re wilting? Is it harmful? If so, what can I do about it?

Jolly Roger,
Colton, Missouri

Your plants look healthy above ground, but if you were to look at the roots, which I don’t advise until the plants are harvested, you will find brown lesions on the roots. This is caused by a fungus called pythium. Pythium damages the roots, impairing their ability to supply the plant with adequate amounts of water. This isn’t apparent except at peak light periods when the demand for water is greatest. Then the shortfall causes the leaves to lose their turgidity and appear wilted. As light intensity falls, the plant’s water requirement diminishes and the roots are able to meet the plant’s needs. The leaves are resupplied with water so they regain turgidity.

Pythium lowers the yield and can even cause plant death so it should be taken seriously. There are several excellent biological controls made from either bacteria or fungi to treat for pythium. They are very effective, non-toxic and are living organisms so they remain active once they are introduced. Here are some products that are available in stores or on the internet.

Trichoderma viridea

T. viridea is a mycoparasitic fungus ? it attracts other fungi such as pythium and other pathogens. It hangs out in and around the rhizospore, the area surrounding the root where the soil, roots and microorganisms interact in a complex biochemical dance. When it encounters a suitable host, it coils around its host’s hyphae (vegetative tissue) and then secretes cellulase, glucanase and other enzymes that dissolve the pathogen’s cell wall and liquefy the sugars and proteins inside the cell. Then T. viridea uses these nutrients. It is a very fast grower and quickly colonizes areas where it is introduced.

Streptomyces griseaverdis

S. griseaverdis is a bacterium that hangs out in the rhizosphere forming dense colonies around the roots. It feeds on sloughed off root material and the roots’ carbohydrate-rich secretions. As its contribution to the symbiotic relationship, it produces indole-3-acetic acid (IAA), a root growth stimulant.

S. griseaverdis protects roots in several ways. First the mats of bacteria form a physical barrier to the root. Second, it produces potent chemicals that inhibit the growth of pathogens. Third, it secretes IAA, a root stimulant. Mycostop is best used as a preventative rather than as a curative, since it cannot get to the organisms that have invaded the roots.

Trichodema harzianum Strain T-22

This is a strain of a naturally occurring soil fungus that lives in the rhizospore and forms a barrier that competes with fungal pathogens for space as well as for the roots’ secretions and dead cells.

T. harzianum uses enzymes including chitinase to dissolve pathogens’ cell walls, and it secretes chemicals that inhibit their growth.

Bacillus subtilis

B. subtilis is a soil bacterium that colonizes the rhizosphere and destroys fungal pathogens using chitinase to destroy their cell walls and other enzymes to digest their nutrients before ingestion. It also secretes fungal growth inhibiting enzymes.

Gliocladium virens

G. virens is a soil fungus that attacks pythium and other fungal pathogens using enzymes to destroy their cell walls and liquefying the contents. It also sends out toxins that paralyze the pathogens. Unlike some of the other protectants, it isn’t persistent so soils must be re-inoculated monthly.

This is the hardest kind of hermaphrodite to control. The male flowers are interspersed with the females on the same bud, rather than on different parts of the plant. In this case, the male flowers appear just as the female flowers ripen, so they need not be removed. These flowers contain female-only pollen.

Hot in the Desert

I live in the desert. It gets very hot in the summer. My plants last year did well during the grow stage, but during the flowering stage I think it was too hot and the buds were damaged. They looked killer, with lots of trichomes, but the taste left me wanting, and the high was just okay. Should I be using shadecloth? During the summer the temperature ranges from 90-105 degrees F during the day in the months of July, August and September.

Doug S.,
Inland Empire, California

I’m stumped. I’ve seen marijuana grow with good potency and fine taste in some very warm areas, such as southern India and the southwestern U.S. I don’t know if the shade cloth would help because it would lower the light intensity. I don’t think it would affect the temperature much. Are you sure it’s the environment that’s causing the poor quality? One possible cause is that are you are growing strains with mediocre genetics. Another may be that you are harvesting a little too early.

Do any readers have an opinion about the cause of the disappointing grow and how to solve the problem?

Starting Seed Company

For the last year I have been planning to start a Web seed business. I am taking a course on Web site design and reading all the literature about it that I can get my hands on.

I have plenty of seeds that are crosses of hybrids. For example Passion #1 x Jack Herer. I know I am assuming that the original seeds were stabilized, but I have noticed that several seed companies operate in this manner.

I have 6 different crosses. Is this enough to get the ball rolling? I want to be successful, and happy customers are my main goal. Is this method going to have too much randomness?

Is there any in depth literature on seed production that you could recommend?

Seed Siren,
Kent County, England

Both the Jack Herer and Passion #1 are F1 hybrids. According to Sensi Seed Bank, the originator of the hybrid, Jack Herer is a cross of three hybrids. The result is that planting a pack of JH seeds will result in a complex of plants that look somewhat similar but are not uniform. This is because the hybrids used to produce the seeds were not stabilized.

When plants from two stable varieties are crossed, the first generation of hybrids is uniform because all the plants received the same DNA. When two of these F1’s are crossed to produce the F2 generation, the distribution of genes becomes random because each plant carries two versions of each gene, one from each parent. It contributes either version of the gene to its gametes.

To stabilize a hybrid, similar plants are bred together or inbred for five or six generations. If the selections have been made skillfully the genetic pool is narrowed and subsequent generations will be fairly uniform. At that point, they are ready to be bred to create a new hybrid.

Another technique is to cross plants from the F1 generation and pick selected plants for inbreeding. These are just two methods of selection. There are many more techniques that have been developed in classical breeding. Many texts on genetics and breeding techniques are available. Perhaps the best book for you to start with is Marijuana Botany by Robert C. Clarke.

In your letter you never mentioned a goal regarding breeding. Are you just randomly crossing varieties hoping you’ll get something good or do you have a vision of a plant with unique qualities or better adapted to its environment? I have some concern about this. What makes your new hybrids any better than the plants they came from? Why would people buy your seeds rather than the seeds of an established company? The noted business consultant, Jane Klein, has remarked that the way to get ahead in business is “Be the only, the best, or the cheapest.” Where do you fit?

This 3 x 3? garden fits up to twenty-four 6-inch-square containers. Each plant is staked so it stands up straight. Each bud gets its share of the light so the clones grow uniformly. (This variety is M-39, progenitor of Max 49.)

Pruning for a Small Closet

I am growing 4 plants in a 2 ft. x 2 ft. x 4 ft. box with a 200w HPS. Midway through flowering, the plants bush out too much and block light to the lower branches. Do you know of a trimming method that encourages upward growth with small internodal spacing? My nighttime temp is only 6 degrees Celsius (10 degrees F.) lower than the daytime temperature. Please help tame the BC Big Bud. Much Thanks!

Big B,

When the top canopy is filled, little light can reach the undercanopy. Here are some ways of getting the most out of your light:

Keep the buds upright using stakes or netting. This prevents shading of other buds.

Remove fan leaves that shade buds. It’s more important to get light to the buds than the leaves.

Remove small lower buds that have little potential. They use the plant’s resources, create humidity and restrict airflow around the plants.

Don’t harvest the plants all at once. Take no bud before it’s ready. Instead, cut only the ripe buds. Leave the other buds on the plant and let them ripen now that they have more access to light.

Copyright by Ed Rosenthal. All rights reserved. First magazine print rights to Cannabis Culture magazine. No other reproduction of this material permitted without the specific written permission of the author/copyright holder.

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