I have some seeds I found in my desk that are more than 20 years old. Will they grow?KR M.

Ed: Probably not. Seeds expire fastest when they are kept warm. Cool (refrigerator) temperature extends their viability. Constant freezing preserves the living seed for years. Seeds kept in a desk drawer at room temperature usually have viability for just a few years. If you have a large number of seeds you could crack a few open to see if the little embryo inside is still alive fresh and alive. If they are dried or deformed, then they are dead or damaged and will not germinate.

Old seeds also take longer to germinate than fresh seeds.They may take up to two weeks to pop. The reason for this is that the enzymes and hormones used for the process have lost their chemistry or evaporated. With fewer enablers, the germination process slows.

The hormone and enzyme deficiency creates viability problems. Most seedlings die soon after germination, after their cotyledon leaves or first set of serrated leaves open. Only a small percentage of them usually get past this point. These plants are usually weak, rather than vigorous. They are not necessarily a wasted effort because they can be used for breeding.

There is a general assumption that one reason germination is prolonged is that the shell has hardened and is more impervious to water, so it has a hard time penetrating the shell. I don’t think this is so, instead that the problem is internal, with the embryo, as I described above.To alleviate some of this difficulty, it’s suggested to scuff the shells using a fine sandpaper, or to slice them slightly with a knife. Others suggest soaking them in water with additives for 24 to 48 hours to start the germination process.

On the other hand, using DMSO, which helps water penetrate both the shell and cell membranes while carrying solutes with it, some experimenters were able to increase germination rates, but the seedlings all died within days or weeks. Perhaps using DMSO and humic acid and Nitrogen (N) as described below might help with survival.

Recipes call for eight ounces water and include quarter- to half-teaspoon hydrogen peroxide, quarter-teaspoon humic acid and/or molasses or sugar. These are of marginal value, regarding germination, but the humic acid and sugars may provide some strength to the seedlings.

Plant the seeds shallowly in sterile planting media and add mychorrizae. Use the humic acid and molasses formula as well as a small amount of N such as an eighth of a teaspoon of high N fertilizer with micros, fish emulsion fertilizer, or high N guano. This will support the initial growth and may help the plants to start photosynthesizing fast to get past the vulnerable post-germination stage. Use a heat mat to keep the temperature at between 72 and 74 degrees Fahrenheit.

Expect to wait to see the seeds germinate – light spray with the water formula might help. Hope for miracles–that is, a viable plant.


I saw an electronic magnifier that plugs into your computer. You can use it to spot pests. Do you know where I can find one? Nathanial Ed: Look up digital microscopes on an internet search site such as Google or on the sales sites. You will find scopes ranging in price from a few to thousands of dollars.


Are all THC molecules the same? If so, what works in conjunction with it to change the effect and experience of one strain’s euphoria vs. another’s laid back effects if they both have the same percentage?Michael

Ed: In most cannabis, you will find mainly THC. Often varieties have small amounts of other cannabinoids. Some of these other cannabinoids, such as CBD and CBG, have calming effects, but are not psychotropic. None of the cannabinoids have an odor.

You have probably noticed that odor is related to cannabis’ effects.These odors are produced by terpenes, the ingredients of plants’ essential oils. Essential oils and the terpenes they contain are the key ingredients in aromatherapy. They can have both physical and psychological effects.

Dr. Rafael Mechoulam, who discovered THC, calls the combined effects of THC (and perhaps other cannabinoids) and the terpenes the “entourage effect.” He described what millions of marijuana users had discovered long ago: the terpenes and THC affect the body’s processing of each other and change the entire experience. Together, they are responsible for the strain’s different effects.


In your book, Marijuana Harvest, you talk about finishing products and their ingredients. I have been growing for about seven years (two) rooms using a popular brand’s planting mix and fertilizers products with success. Now I’m wondering if I‘m missing out by just sticking to one line?Papa Yahoo

Ed: If you are curious about some of the bud enhancers and finishing products mentioned in Marijuana Harvest, you owe it to yourself to experiment with them. Set aside a separate space or separate irrigation system to test them against your standard fertilizers and enhancers and make sure to keep all other conditions the same.

The manufacturers of these products depend on repeat sales. If they don’t work, who will buy them a second time?


For the past two years, botrytis has attacked my crops. I only use organic and environmental friendly products to manage this problem. It comes back right before harvest.

The plants are grown in a greenhouse with raised beds, so changing the soil is not much of an option. It is well ventilated with drip irrigation. I foliar feed at night. I have been growing the same strain for the past two seasons. Should I change varieties? If the botrytis is present once, is it always present? Should I spray the whole greenhouse with a bleach solution, but what about the beds?

The first step I’m taking is to learn about soil health and to improve the diversity of microorganisms. The second is, stopping monoculture, which I’m seeing as not the correct way of growing any crops. So, I am adding companion plants, which will work as natural pesticides and nutrient cyclers. Third, is to never let the soil be exposed, as to improve soil life and health. I’d like to think these steps I’m taking go hand in hand with preventing pest invasions and pathogens.

Is there anything more that I can do to fix the problem once and for all?Mikaela

Ed: First, let’s clear up your confusion regarding pests and diseases. Pests are animal kingdom creatures. Diseases are caused by pathogens such as yeasts, bacteria, and viruses. Botrytis is a disease caused by a fungus, Botrytis cinerea. Its spores are airborne and not related to the soil.

Botrytus is an environmental disease. As was mentioned, Botrytus is airborne and it’s everywhere, so it will come in contact with your plants. Its spores germinate easily when the relative humidity is more than 50 percent and the temperatures range from the mid-50s to the low 70s. When you foliar feed at night, you are increasing the RH to unacceptable levels. Stop increasing relative humidity by ceasing all foliar feeding from the second week of flowering.

Botrytus germinates in acidic conditions. By spraying a 10-percent milk solution or pH up on your plants, the surface pH will change to unfavorable for the fungus–alkaline. Potassium carbonate also works well as a spray up to the first three to four weeks of flowering. These are good to spray on after a rain to prevent germination of spores spread by raindrops.

Certainly improving the quality of the planting mix using bio- culture such as mycorrhizae, trichoderma, and other beneficials is a good idea, but it won’t affect B, Cinerea. However, keeping the soil loosely covered helps thwart thrips and fungus gnats, lower humidity, and increase time between irrigation. If you have a light deprivation greenhouse, set it to harvest the plants before the time they are usually attacked. If not, change to varieties that are normally harvested before Botrytus season starts.

I don’t recommend that you grow companion plants in the greenhouse. By keeping it just cannabis, you can cater to its needs and not make any compromises.

During both day and night, keep the temperature in the mid- 70s or higher, above the high end of the range for the fungus. During the day, it can climb as high as 85 degrees, increasing the plants’ growth.

If you are located in an area with high RH during the year, you might consider growing in a closed loop greenhouse. Rather than using ventilation as part of the environmental controls, condition the air in the greenhouse using air conditioning and dehumidifiers. This will eliminate the disease by lowering the humidity below 50 percent, outside the fungus’ environmental range. This also gives you a chance to clean the air so it contains fewer pathogens.

UVC light is used to control powdery mildew. The light passes over the plants for just a few seconds daily, but it kills the pathogens and its spores. There are controlled ways to use the light without coming in contact with it since it is also harmful to humans.


I am an 18-year-old high school senior living in Illinois. I want to pursue my dreams of becoming a master grower. I plan to attend Oaksterdam University, then my community college before transferring to Northern Michigan for medicinal plant chemistry. I spend hours doing research and studying, reaching out to growers, pretty much anything I can to expand my knowledge in the field of marijuana. I want to be the best I can possibly be. I was wondering if you had any advice, tips, secrets, or opinions on my plan, just anything that can help lead me in the right direction in this industry.Andrew

Ed: Your goals and plans seem reasonable to me. Illinois is opening up to legalization and so are its neighbor states, so you will be working in an industry with excellent growth. Many new people will be needed to run things. Your idea of getting formal education that is industry based through Oaksterdam and then to get a degree in agriculture and chemistry is laudable. My one piece of advice: while you are getting your education, intern with someone or an organization you respect to get a feel of things and to network.


I’m growing on the island of Hawaii. I moved my indoor vegetative outside where we have at most 14 hours of light on June 22, the longest day of the year. We turn the lights on at 9 pm, 12 am, and 3 am. How long should each blast of light be? Doing ten minutes now. Cyrano

Ed: An individual leaf needs only a few moments of red light to restart the count to a critical darkness time period.The chemistry that deals with this is changed back to the active state, which prevents flowering, with just a short light duration. The reason the lights stay on longer or move is to make sure that most of the plant receives the light. Even a gentle wind causes movement, exposing more of the plant to it. A moving light changes its angle in relation to the plant, also exposing it more completely.


I am at the force flowering stage and I have noticed that, within a few minutes of the lights going out, the plants wilt severely and when I check on them for the next 12 hours they are still wilted. After the 12 hours are up, the lights turn back on and they look great. Is there a problem here?Mike C.

Ed: Plant leaves drooping at night is not a problem. It costs the plant energy to maintain the turgidity needed to maintain leaves upright. Since they are not attempting to catch moon- rays, during the dark period, the plants let the leaves hang looser since there is no advantage to keeping them upright and it costs them energy.

This is a phenomenon common not only to cannabis, but to other plants as well, including many trees and garden plants. Using time-lapse photography, you will notice leaves in different positions during the 24-hour circadian cycle. It seems to react to light rather than time, although plants “learn the cycle” and anticipate events based on repetition.

Sometimes, leaves begin to droop on plants several hours before lights go out. This may mean that the leaves are maxed out on light for the day. They have had as much as they can handle and are not trying to capture any more for photosynthesis.


One week after adjusting the lights to 12-12 for flowering, the lights were left on for 36 hours. That was one 12-hour period that was supposed to be lit, 12 hours that should have been off but were left on and the regular 12-hour lit period again. What should I do?James Harvey

Ed: The plants will take it in stride and it will have little total effect on flower yield or quality. You should get a timer that is reliable and start using it immediately.


I have a couple of indoor plants that are five weeks into flowering. They are not developing well. The buds are tiny, very airy, and sparse. They are very different than my past results and look more like two or three weeks of flowering instead of five weeks. Upon closer inspection, I noticed one of my timers was at fault. During the 12-hour dark period, all through the five weeks, this timer was coming back on for 15 minutes after being off for three hours.James Harvey

Ed: The space would go dark, and then, three hours later, this one light would come on for 15 minutes and then go off leaving the room dark for the rest of the period (eight hours and 45 minutes). The problem has now been fixed.

Assuming the plants look like they are at two or three weeks flowering stage, should I just let them flower for another five weeks? Then they will flower for a total of 10 weeks, although the variety usually takes only eight weeks to flower. Do you think they will take more time to develop or will they just reach maturity at eight weeks?

As you described, the plants were receiving mixed signals about flowering. This has affected the growth. I think your speculation that it has also affected the chronological pattern of development is correct. The plants’ development is at an earlier stage than the five weeks the plants have spent in flowering.


The plants are two weeks into flowering and all the plants have immature seeds in every node and calyx. What can I do to save it? Is there a chemical that will stop those seeds from maturing? Other than this, things are growing faster than I’ve ever seen. The plants have never had nugs this big in week two. – Jim

Ed: First question: Have you found the culprit? Was it a male or a sneaky hermaphrodite? Or was it a result of general hermaphroditism in the group? If the latter, then there is no stopping the seeds because of continued pollination from new male flowers. The buds will best be used for concentrates. If the seeding was the result of sloppy male inspections or a few sneaky hermaphrodites, then with their elimination, any new flowers will be seedless. If it is only lightly seeded, new flowers will start growing. These flowers will be seedless, but will be part of a bud or cola that contains seeds. If the buds were heavily seeded, there is a good chance the plants will go into senescence as the seeds mature. There is no chemistry I know of which will reverse the damage caused by the pollen.


In the section called “Nutrient Deficiencies” of your Marijuana Growers Handbook, you wrote about some minerals being “mobile”, where others are not. What does the term “mobile” mean in this context? – Leslie K.

Ed: Mobile nutrients can move around the plant to the section where they can be used most advantageously. Nitrogen (N) is one such nutrient. If there is a deficiency, the plant moves the element from lower portions to the top of the canopy. Other mobile nutrients are Phosphorus (P) in the form of phosphate, Potassium (K), Magnesium (Mg), Chlorine (Cl), Zinc (Zn), and molybdene (Mo).

Immobile nutrients have a fixed position in the plant. Once they are absorbed into the tissue, they are locked in place. They are Calcium (Ca), sulfur (S), iron (Fe), boron (B), and copper (Cu).


The CO2 level in my sealed grow room goes up to 2000 ppm and higher during the dark period. Is this negatively affecting yield and quality?Victoria

Ed: I don’t think that plants will indicate a stress mode from 2000 ppm CO2 during the relatively inactive dark period. The plant absorbs CO2 only during the lit period when it is photosynthesizing.

The CO2 level rises during the dark period because it continues metabolic, that is, life processes and growth, during the dark period. It burns the sugar it has produced for energy to engage.

Leave a Reply