When To Harvest Marijuana

There is more to harvesting marijuana plants than just cutting them down. Before harvesting, the plants should be fed plain water only (no fertilizer) to remove any fertilizer that has built up in the plants themselves, and the hydroponic media or soil they were grown in. After the plants are harvested, they have to be manicured and dried.

Even with a small indoor or outdoor garden (less than 20 plants) it can take a few hours to harvest, manicure, and hang the buds for drying. A large garden (more than 50 plants) may take a full days work, or longer. The plants must be manicured and hung to dry right after they are cut down, and this can be time consuming.

Make sure you leave yourself a steady 6 hours of time to work, the first time you harvest a small garden. Make sure you leave yourself a day to work, the first time you harvest a large garden. You can base the time it will take to harvest future crops based on the amount of time it takes to harvest your first crop.

If you have grown a particular marijuana strain before, you will have a good idea when it will be ready to harvest. If you are a first time grower or if haven't grown a particular strain before, try to get your seeds from someone who can tell you not only what strain it is, but also the expected harvest time.

The reason why it is so important to know when the plants will be ready to harvest is because prior to harvest, you will need to remove the nutrients (fertilizer) contained in the plants. The plants themselves and the hydroponic media or soil the plants were grown in will store some of the nutrients that have been fed to them.

Marijuana plants need fertilizer so they can grow, mature, and produce THC. In order to remove fertilizer from plants, you feed them water (with no nutrients) for one or more feedings just before they are harvested. Tap water will have some chemicals present, it is best to used distilled water or water treated with reverse osmosis for this purpose.

When you know the approximate time the plants will be ready to harvest, you will be able to wait right before you are going to harvest and give them water with no nutrients. In this way they are allowed to grow for the maximum amount of time (large harvest) before being flushed.

The plants will use up the fertilizer they have stored in them and growth will not slow down, if done properly. If nutrients are not flushed from the marijuana plants, the resulting marijuana will taste bad and may also be hard to ignite.

If you are growing hydroponic marijuana, start clearing about 7 days before harvest. This can be done by changing the solution and using only distilled water or water treated with reverse osmosis (no nutrients). Some growers will change the water two or more times before harvest because the media may hold nutrients.

With soil you need to change to distilled water or water treated with reverse osmosis about 14 days before harvest. Avoid slow release fertilizers because they are hard to remove. Growers that have to use slow release fertilizer can use regular nutrients for the last month.

Indoors, if you know that the marijuana strain will be ready to harvest 8 weeks after flowering is started, switch to distilled water about 7 weeks after flowering. Outdoors, if you know that the marijuana strain will be ready to harvest in the middle of September, switch to distilled water at about the beginning of September.

When growing in soil, you can stop watering the plants 2 days prior to harvest. This is not essential but it will speed the drying process. If you try to stop the water supply to hydroponic plants, they will wilt and begin to die within a few minutes to a few hours.

Harvesting Marijuana Plants

The optimal time to harvest marijuana plants is when THC production has reached its maximum. A rough guide as to when to harvest is to wait until 50%-80% of the white pistils (hairs) have turned dark (usually brown or red). But a better method of determining when to harvest is to wait until certain trichomes on the plant have matured.

Trichomes are small appendages that look like hairs, they are produced by marijuana and other plants. Some trichomes on marijuana plants develop a resin gland at the top. These trichomes are a rich source of THC, and monitoring them will allow you to best judge when the plants are ready for harvesting.

On marijuana plants, trichomes with resin glands form in the highest concentration on buds. They start out clear, turn a milky color, then turn amber (light brown). To best judge when to harvest, wait till about a week or two before the expected harvest time (when you go to water only feeding) and look at the trichomes on the largest buds on each plant daily.

The best time to harvest a marijuana plant is when a majority of the trichomes have turned to a milky translucent color. See these images of what trichomes look like and what color they should be at harvest time. Not all the trichomes will mature at the exact same time, so harvest when most of the plants are ready.

It is very hard to see the trichomes with the human eye, so some type of magnification is needed. An inexpensive way to effectively view them is to use a 10x or 15x magnifying glass or a pocket microscope rated at somewhere between 20x to 70x.

There is another type of trichome that can be found on marijuana plants, they are called cystolith trichomes. This type of trichome is mainly found on the underside of leaves. They look like small hairs with no resin gland at the top. Cystolith trichomes are not a source of THC.

When grown indoors, most marijuana strains will be ready to harvest 6-12 weeks after starting a flowering light cycle (12 hours on, 12 hours off per 24 hour period). Most mainly indica strains will be ready to harvest in 6-8 weeks. Mainly sativa strains can take up to 12 weeks to reach maturity.

You can harvest the plants by cutting them down at the base of the stem (with a pair of scissors or some other type of cutting tool), just above where the plant meets the hydroponic media or soil. This will allow you to harvest the entire plant at the same time. Alternatively, you can cut off each branch separately.

If you are a spiritual person or feel a connection to living beings, offer a prayer of gratitude (and thank the plants themselves), before cutting the plants down. You can do this silently, if you feel more comfortable doing so.

Once you have grown a strain, you will be able to better estimate the best time to start giving it distilled or reverse osmosis water to flush nutrients, and when to harvest future crops. Indoors you can be pretty sure that a strain will be ready in the same amount of time, if you provide the same conditions each time you grow it.

Indoors growing conditions will remain constant, unless you change something. When you grow outdoors, you can not assume that a particular strain will be ready in the same amount of time, each time you grow it. This is because you are not able to provide consistent conditions outdoors.

After the marijuana plants have been harvested, they must be manicured and dried. Manicuring and drying the marijuana harvest is a very important part in the cultivation process. You may want to smoke the marijuana you have grown without waiting, but this is not a good idea. See this for information about manicuring, drying, and curing marijuana.

Marijuana Horticulture:
The Indoor/Outdoor Medical Grower's Bible

Includes 21 pages of info about harvesting and drying marijuana, with a few dozen color images. If you were only going to get one book about growing, this book would be the best choice. Describes growing marijuana indoors and outdoors (with hydroponics or soil).

Also provides information that you can refer back to when things go wrong. A very comprehensive reference book for anyone interested in growing marijuana, either indoors or outdoors. Recommended for beginners and more advanced growers. Over 500 pages with more than 1000 color images.

Marijuana Chemistry:
Genetics, Processing And Potency

Explains the various cannabinoids that marijuana is made up of and how things like growing conditions, harvesting, processing, affect the potency of the final product.

Lots of tables, graphs, and other info. Recommended for the intermediate and expert marijuana grower, this is heavy on chemistry. If you do not have a very good grasp of science and chemistry this book is not for you.