Resources - Marijuana Growers

Colorado Medical Marijuana Growers Help Guide produced by

So you want to be a marijuana farmer? Once you obtain your Medical Marijuana Card you can legally grow 6 plants, 3 flowing, 3 growing. This document provides helpful hints on growing your own medical marijuana. Producing good quality medical marijuana is very difficult; hopefully this will help you make good choices to minimize your failures. It will take some experience to produce quality medical marijuana. This is one of the most amazing plants really. It has medical purpose yes, but also a possible fuel source, the rope like hemp quality, the oils from hemp produced a number of usable products from what is essentially a fast growing weed. Deer love to eat the flowering weed plant, should you attempt to grow outside, you will have to deal with that issue. The weed cannot be easily killed, and it grows at an incredible rate.

Plant Cutting & Seed Germination

The plant you start with is the most important part of the process. Like good quality DNA, you want to start with the best possible plant specimen. The best thing to do is get a clone or cutting from your local dispensary or caregiver of a plant known to be of good quality. Remember there are as many marijuana types as there are dog and cat types. There seems to be no end to the new variations. If you start with a clone, you are most certainly starting with a female plant, which is capable of producing the flowers or buds. Male plants serve no purpose in production and should not be introduced into the environment. Should male plants be introduced into the environment during the flowering stage, the female plants will stop flowering and start producing seeds. The medical potency of the plant will be lost once the plant produces seeds. The term “sensimillia” or sex starved is used for female plants that flower and have no male plants in the environment. Sensimillia comes from the spanish words "sin semilla" meaning "without seed". It is actually pronounced sin sumeya which simply means weed without seeds. This is one of the most important aspects to produce quality medical marijuana. You can also produce plats from seeds, and seed banks in Holland and Canada have incredible species. These out of country seed banks are just that, out side of the USA. Should you want to start with seeds, one way is to wrap the seed in a damp paper towel and place it under 24 hour light until the seed sprouts. Keep the paper damp until the seed sprouts. Some people believe 24 hour light will help make the seed sprout female, but we have no proof of this theory. Once the seed sprouts, place it under 1/4 - 1/8 inch of soft soil or in a starter rock wool cube and wait for it to break surface. The seed sprout will turn upward by instinct. There is no way for sure to prove the plant sex until the plant starts to flower. Male plants will produce ball sacks, and female plants will produce gel type hairs. Should you discover your plant is male, kill the plant and remove it from the environment.

Baby Marijuana Started From Seed

Four week old plant started from seed. Plant sex has not been determined.

Baby Marijuana Started From Seed

Four week old plant started from seed. Started in wet paper towel and planted in soil after germination.

Growing Environment

You want to choose a good growing environment. Your Room is important, you want high ceiling for one thing, good ventilation, a convent source for water, and a place that is not going to offend others with the resulting smell. You want to give the plants room to grow, remember it is not the number of plants you have, it is the amount of light and grow space available for the plant. Fact is I can produce just as much with three plants in a given space then I could with 12 plants in the same given space with the same amount of light. So give your plants room to grow and provide them with ample light. We recommend you go hydroponic, but growing in soil can also produce quality medical marijuana. We recommend you shut out all light sources like windows and only expose the plants to halogen based lights from 400 to 1000 watts. Place the lights under heavy duty timers so you can regulate the amount of sunlight your plant gets. Remember HEAVY DUTY TIMERS because the 400 - 1000 watt lights send a lot of juice through the plug and they get very hot. Be Safe, We have seen grow rooms burn up transformers outside the house on the power poles, so distribute your power plugs if you can.

Making Clones

Your going to need to learn to take cuttings of your mother clone plant to produce new clones. The process is very simple, but delicate, and should you disturb the cutting or hurt the cutting during the early stages it will stunt the plant for up to 4 weeks. In order to start taking cuttings you need a healthy mother plant with 4 - 6 inch segments available to take cutting from. The mother plant should be healthy and pest free. You will need rock wool cubs or soil containers to place the cutting in. You will also need some rooting gel or root-tone powder to help stimulate root growth on the cutting which can be found at any wall mart garden center. Find a razor blade or very sharp knife to make the cutting from the mother plant. Cut the plant about 4 to 6 inches from the top of any stock at a 45 degree angle. Be very gentle do not bruise the cutting or bend it. Dip the cutting in the rooting gel or if rooting powder, dip it in water then into the powder covering the bottom 1/3 of the cutting stock. Gently place the cutting stock in the rock wool cube or in the soil container making sure to pinch the wool or soil around the base of the cutting making sure to leave no air pockets. Air pockets will stop the roots from growing. Once you have done this DO NOT DISTURB THE CUTTING TILL YOU SEE GROWTH. If you disturb the cutting you will stunt the growth for up to 4 weeks. Once the cutting start to grow you can move them. Keep the cuttings wet and under 18-24 hour light cycles.

Marijuana Mother Plant taken from a clone

Clone mother plant used to make other clones. Type is "Sour Diesel"

Marijuana Mother Plant clone segment

Marijuana Mother Plant clone segment we plan to take a cutting from. Pinch off the lower branch segments on the stem creating a 2-3 inch bare section.

Marijuana taking cutting

Gently cut the stem after you have trimmed the stem area.

Marijuana Mother Plant clone segment

An example of a cutting. Now it is time to put on the rooting compound.

Marijuana Mother Plant taken from a clone

If using powder, place the stalk in water, then dip it in the rooting compound

Marijuana Mother Plant clone segment

Many rooting hormones are available. Gel and powder, they all work. This one cost about $5 at your local Wallmart garden center.

Marijuana making clone

The cutting just before putting it in the soil. You could also put it in a rock wool cube if you were using hydroponics.

Marijuana making clone

VERY IMPORTANT to squeeze the soil or rock wool and leave NO AIR POCKETS. Air pockets will inhibit the roots from forming, and it will take a month or more vs. a week or two for the cuttings to grow.

Marijuana making clone

Again squeeze the air pockets out. Pour in a little water, NO FERTILIZERS, just fresh water. DO NOT TOUCH OR BUMP THE CUTTINGS till you see growth. The root structure will develop if left undisturbed in about 10 days. If you disturb the cutting or have air pockets or fertilize then you will not have good results. The plants will stretch first and you will see a good green color in the center. Then the cutting will start new growth. If the plant is disturbed it will go into shock and it will take over a month or more for it to start growing. Keep it wet and under 24 hour light. If you do not water the cuttings, they will die, keep them wet.

Clone Assembly Systems

There are may cloning systems available. This section will review clone making systems, and other cloinging and growing tools.

Clone video Using the clone assembly.


High Intensity Discharge (HID) lamps are the best solution for most indoor growers. HID lamps come in 3 basic flavors: High Pressure Sodium (HPS), Metal Halide (MH), and Mercury Vapor.

HPS High Pressure Sodium (HPS) – Crop will mature slower then (MH) but yield more. Best choice of light for efficient use of electricity.

Metal Halide (MH) – Has an improved spectrum, higher intensity. Quicker grow time. Intense light will burn the plant if too close. No as efficient energy use.

Mercury Vapor (MV) – fluorescents and mercury vapor least expensive but cost more energy to run per watt of use. (MV) color spectrum is not as good as (MH) or (HPS).
(MV) will put out about 8000 lumens per 175 watts

(HPS) will put out 15000 lumes per 150 watt twice as efficient. A 400 watt (HPS) will output around 45000 lumens.

(HPS) is high in reds, which works well for flowering, while the (MH) Metal Halide is rich in blues, needed for the best vegetative growth.

There are also Halogen arc lamps that generate too much heat and not very much light for the wattage they use, and are also not recommenced, even though the light spectrum is suitable for decent growth.

Lamp Type Watts Lumens/bulb Total efficiency
Fluorescent Bulb 40 3000 30k lumens
Mercury Vapor 175 8000 20k lumens
Metal Halide 400 36000 36k lumens
High P. Sodium 400 45000 45k lumens

Notice the Mercury Vapor lamps are less efficient than the fluorescent (FL), and can’t be positioned as close to the plants.

There is a new type of HPS bulbs called Son Agro, and it is available in a 250, 1000, and 400 watt range made for greenhouse use. The 400 is actually 430 watts; they have added 30 watts of blue to this bulb. It is a very bright lamp (53k lumens). These bulbs can be purchased to replace normal HPS bulbs, so they are an option if you already own a HPS lamp. Son Agro bulbs however, do not last as long as normal HPS bulbs. There is something like a 25% difference in bulb life. But you can expect bigger and faster yield with these bulbs.

For every 500 watts of continuous use, you use about $20 a month in electricity, so it is evident that choosing a lamp taking half the power to output the same lumens will pay for itself over time.

We recommend using HPS lamps if you can afford the initial cost. On the long run the HPS lamps will save you money over fluorescents, and you will produce much better plants with better lights. The cheapest solution for HPS is comes in the 70 watt size at the home improvement stores. This size is not very efficient, but blows away FL in efficiency, so they might be an alternative to FL for very small operations, like 9 sq. feet or less. Over 9 sqr. feet, you need more light than one of these lamps can provide, but you could use two of them. 70 watt HPS lamps cost about $40 each, complete. Two lamps would be 140 watts putting out about 12000 lumens
Horizontal mounting of any HID is a good idea, as this will boost by 30% the amount of light that actually reaches the plants. Most HID's sold for indoor garden use these days are of this horizontal mounting arrangement.

The biggest problem is that the mid size lamps like the 150 and 250 watt HPS are almost as expensive to buy as the larger 400's. For this reason, if you have room for the larger lamp, buy the 400. If you plan to go it like a pro, a 1080 watt model is available. You might find there is better light distribution from two 400's rather than one large lamp. Of course, the two smaller lamps are more expensive to purchase than one large lamp.

Heat buildup in the room is a factor with HID lamps, and just how much light the plants can use is determined by temperature, CO2 levels, nutrient availability, PH, and other factors. Too big of a lamp for a space will make constant venting necessary, and then there is no way to enrich CO2, since it's getting blown out of the room right away.

Lighting Cycles

Plants need 12 hours of uninterrupted darkness or more to trigger flowering.

For Germination and cuttings we recommend 24 hours of light till plant is 12-15 inches high

For vegetation growing hours we recommend 18 hours light, 6 hours dark cycle as the best growing till plant is large enough to produce desired yield.

For flowering state 12 hours light, 12 hours dark cycle is best for budding for 8 – 16 weeks determined by species, light and environment.

With that said there is a large number of theories including 24 hour light is good for germination and can help produce female plants. This is debatable, the theory that 24 hour light during germination helps determine sex of plant. Also there are theories that cutting the light back during the flowering stage slowly can be helpful. Basically the only real important point is flowering requires 12 or more hours of darkness in a 24 hour cycle. Any light cycle will work if you keep the flowering darkness rule in place. Once you start a flowering cycle, you should continue till harvest. It is true you can change the plant from flowering to vegetation by going back to vegetation lighting. But if you have been flowering for months, you most likely have gone past changing it back to vegetation state. You can flower a plant any age, but the resulting size of the harvest will be much less then if you grew a plant 2-3 months first then start to flower.


The plant will show his or her sex as soon as it starts to switch to the flowering state. This is the only sure way we know to determine sex, although there may be other ways. The females will start growing gel like hairs at the branch segments. The males will produce what we will call a ball sack, and no hairs. If you do have a male in the group, kill and dispose of the plant as it will only reduce the quality of your medical marijuana. The remaining female plants will become sex starved or “sensimillia”, and spend all there energy producing potent buds. The buds will not get any male pollen, and continue to grow bigger better more potent buds until you harvest the plant, or it gets pollinated by a male. Don’t be surprised to see the female plant produce male branches at the bottom darker areas of the plant. The female plant will actually change sex at the base, just pinch off those segments or male parts, or you will see them eventually flower and produce pollen from the base of the female plant. You will not see this happen till the later part of the budding cycle.


If you go hydroponic you will most likely not have to deal with pests. I figure this is because the pests live in the soil. If you do go with soil, you will have to deal with the pest spider mites. The mites live in the soil and under the leaf and they are the size of aphids you find on aspen trees. When the plant flowers they will explode in population and spoil your crop. If left unchecked they will web up the flowers and suck the life from the plant. The plant will be weak yellow. The mites will attack the plant in vegetation state, and you want to get them in check prior to flowering. Some people cook the soil in the oven to kill any organisms in the soil as a precaution for not getting spider mites. If you do find spider mites we recommend you wash the plant with dawn dish washing liquid in warm water. Wash the leafs; top and bottom lightly so not to damage the plant. Stir up and wash the soil as well with the soapy water. Continue this for a few weeks until signs of infestation disappear. Remove the older leafs and dispose of them away from the plant over the washing period. Over a few weeks the plant will turn dark green again and you should be OK. Keep an eye out for a relapse. There are other methods but this is one proven to work.


PH is measured on a scale from 1.0 to 14.0.

Pure water has a pH of 7.0 and is considered pH neutral.

PH below 7.0 is considered to be acidic.

PH higher than 7.0 is considered to be alkaline.

A substance that decreases pH (pH-down) is called an acid.

A substance that increases pH (pH-up) is called a base.

A substance that helps nutrient solutions resist pH changes when an acid or base is added is called a buffer.

It is very important to keep the pH level within certain limits when growing marijuana. Marijuana growers need to monitor the pH of their nutrient solution and keep it within optimum levels.

The pH level of your hydroponic nutrient solution or soil will determine how well your plants are able to absorb nutrients. If the pH level is out of the proper range, the growth rate of the plants will slow down or stop till the plant recovers from the shock.

Purchase an electronic PH METER used to measure the pH of water, hydroponic nutrient solution, hydroponic media, and soil. They tend to break over time, so keep that in mind or purchase one which can exchange the head with a new one. They also have probes and batteries that eventually will need to be replaced.

For accurate measurements always follow the manufactures instructions for calibrating, cleaning, and using a pH meter. Calibrating the meter is especially important because all measurements will be wrong if the unit is miss-calibrated.

When growing hydroponic marijuana the pH of the nutrient solution should be between 5.5 and 6.8. In most cases optimal pH is about 5.8 to 6.3 but this may vary slightly depending on the particular marijuana strain and the growing conditions you provide. You can experiment to see what works best for your particular plants but always keep the pH between 5.0 and 7.0. Or your plants will go into shock for some time.
At the beginning of your crop you will want to monitor the ph often. Over time the level of the PH will stabilize and you will not have to spend much time adjusting it up or down. Measure the pH right after you add the nutrient solution to the reservoir (mix well first) because the nutrients will change the pH level of the water. Check the pH level at least once a week. Keep in mind the rock wool will take time to ph stabilize. We recommend you start with a 5.9 PH and soak the rock wool and run the hydroponic system to get the rock wool PH to stabilize. This will help stabilize the PH early and you won’t have to work on PH up and down.
Adjusting pH of Hydroponic Marijuana

PH-up and pH-down solutions are used to adjust the pH level of hydroponic nutrient solution and hydroponic media when the pH is out of range. PH-up (also called pH increase) is used to rise when you adjust you PH, use only a small amount! A good rule is a capful makes a big change, so add a capful, and recheck the PH the next day after it has well circulated. Continue making changes daily until you get your PH to stabilize without making any adjustments to the PH. You are shooting for 5.9-6.0.

Nutrients for Growing Hydroponic Marijuana

Nutrient (or fertilizer) is food for plants. Marijuana plants need a certain amount of food in order to grow properly. The primary nutrients in plant foods are Nitrogen (N), Phosphorus (P), and Potassium (K).

Plant foods are measured in an N-P-K format
N is Nitrogen
P is Phosphorus
K is Potassium

A 15-15-15 plant food contains:
15% Nitrogen
15% Phosphorus
15% Potassium

A 20-10-10 plant food contains:
20% Nitrogen
10% Phosphorus
10% Potassium

The percentage of the solution not used by nitrogen-phosphorus-potassium is secondary nutrients, trace elements, and inert material.

An all purpose nutrient with secondary elements like calcium, sulphur and magnesium and trace elements boron, copper, molybdenum, zinc, iron, and manganese will get you through all stages of growth. But during different stages of life, you can adjust the different nutrient levels needed at different times to optimize growth.

Regardless of the nutrient you choose, during the first two weeks of growth, use ¼ amount (or less) of nutrient solution the manufacturer recommends for adult growth. Some marijuana growers don't add any nutrients to the water for the first two weeks. They then use a 50% solution for two weeks, then go to a 100% solution.

During vegetative growth the plants need lots of N (nitrogen). They also need a fair amount of P (phosphorus) and K (potassium), 20-10-10, or 30-15-15, or something similar, with trace elements should do it.

During flowering the plants need more P (phosphorus) and more K (potassium) than they did during vegetative growth. They need some N (nitrogen) but not as much as they did during vegetative growth. They also need calcium.

If you used: 20-10-10 for vegetative growth, then try using 10-20-20 (or similar) for flowering.

If you used: 30-15-15 for vegetative growth, then try using 15-30-30 (or similar) for flowering.

Do not give your plants extra nutrients thinking it will make them grow faster. Too much will kill your plants. If you under fertilize, plants will take longer to grow but will not die. You will see the ends of the leaf turn yellow or burning the plant from too much nutrients. Follow the mixing instructions on your hydroponic nutrient package, if you aren't sure, use less rather than more.

As water evaporates and is absorbed by the plants, your water reservoir level will drop. Some growers add tap water that has been aged 3 days or longer to the reservoir but it is not required. Nutrient solution lasts a long time. Some people change the nutrient solution throughout the grow cycle. That is, discard the old solution and rinse off the reservoir, pumps, and other equipment that is used with hot water. This is not required and you can run the entire grow / flower cycle using the same reservoir just adding water as it evaporates. And adding nutrients every 3 weeks.
You only need to clean the cups and tubing the plants are in before you start a new crop. The old solution that you are discarding can be used to water house or garden plants. This will at least double the growth rate if you usually water your plants with regular tap water.


If you are buying nutrients, get the dry powder kind that you mix with water. They are much cheaper over the long run when you compare with already mixed liquid solutions.

Liquid solutions are just as good, but many are primarily water and a good portion of the price you pay is to cover shipping water that you can add at home for free. There are some concentrated solutions that may be cost effective but I've always saved money using dry powder nutrients. We have had good results with many different brands.
Some grower say to stop all plant food at least 14 days before harvesting when growing in a hydroponic garden. The last time you change the water in your reservoir, don't add any nutrients or stop adding nutrients close the end of harvest. This is so N-P-K and other elements can be removed from the plants before harvesting. This will insure that your weed is easy to ignite, doesn't taste like plant food, and you are ingesting a minimal amount of N-P-K or trace elements.

Harvesting & curing

Well you have made it to the end, and your plants look great. When do you harvest? One of the biggest mistakes is to harvest too early. Plants will take about 3 months to reach mature buds. This varies by plant; some are quicker some taking longer. One good rule is to wait till the biggest tops start turning hard and looks cured or when the sex starved female plant starts changing sex at the base and starts producing male parts. Be patient and don’t harvest or take samples till the plant reaches its full potential.

When you are ready to harvest, be prepared to smell up the place, as you already have found out the plants do smell, and when you harvest them they smell much more. Traditionally growers would cut the plant at the base and hang it upside down. We covered a large table with newspaper then covered that with white paper so no ink can transfer to the buds. Cut the large tops first and place them on the paper covered table. They will be the best, save them to the side. Then cut the plant stalk by stalk manicuring the buds into sections of bud clumps. Trim away large leafs and save them for making butter. Do not worry about cutting away the stem segments, because as they dry, they will fall away from the buds over the next few days. Continue cutting up the plant into segments until it’s gone. Now you will have a table of manicured buds with large leafs removed and saved for making butter. Over the next few days rotate the buds on the paper as they dry quickly on the newspaper. The size of the buds will shrink over the next week loosing many times their original size and weight. The smallest buds will be ready for use quickly, within 24 to 48 hours. You can remove the larger leafs and stems easily from the buds as the dry, they will fall away. On the newspaper you can collect the potent crystals and save them for use as you see fit. We liked to store the cured week in shoe boxes make of paper lined in newspaper. This keeps the buds dry and minimizes the chance of getting mold. You can store in a glass jar when you was sure there was no moisture left in the buds. The buds should crumble into a sticky powder when they are ready for use. Be careful not to taint your buds with mold or other foreign elements or oils, the buds will absorb foreign elements like mold, melted plastic.

Colorado Medical Marijuana Growers Help Guide produced by