How To Grow Hydroponic Marijuana

Growing Hydroponic Marijuana Introduction

No literature about growing hydroponic marijuana is totally complete, and this is no exception.  Get some kind of illustrated instructions in electronic or book form to supplement the instructions given here.  Images will make learning and understanding much easier and the details will be more explicit than those presented here. I use Marijuana Growers Guide and Marijuana Hydro Gardens... for references when I'm stuck.  They are also the only instructions I had when I first grew marijuana and they've helped me to grow very good crops.  If you can afford it, get them both. If you are going to get just one book as a reference, I recommend Indoor Marijuana Horticulture.  To view a complete list of books on the subject of growing marijuana, go here. Expect to pay about $500.00 for a light, hydroponic setup and everything else you will need to raise your crop hydroponically.  You can spend more or less than that, but $500.00 is the average initial setup price for a personal garden (5 to 10 plants).  Once you get things set up you can continue to raise new crops with your set up and only have to spend money on nutrients, bulbs, and other maintenance. After a few crops (you will make mistakes at the beginning), your product will be better (if the seeds you used were good) than anything that you would normally buy, at a fraction of the cost. You will get about 1 to 2 ounces of premium tops per plant every 3 to 4 months.  You won't have to deal with people that you might not trust, and your stash will be clean and healthy as can be.

Hydroponic Set Up

All growing described on this page is done using the Ebb and Flow system.  The Ebb and Flow system is the most popular hydroponic methods for growing weed.  It is simple and easy to use. It works like this: A reservoir containing nutrient solution is located below a growing tray.  The tray contains the plants that are in containers with growing medium like rockwool. The growing bed is filled with nutrient solution by a small pump on a timer to feed and water the plants.  The timer then shuts the pump off and the nutrient solution drains freely back into the reservoir. Ebb and Flow systems' are favored because of their low maintenance, high productivity, and ease of use.  Ideal not only for the beginner, but for the advanced gardener as well. Most, if not all the information presented can be adapted to work with other forms of hydroponic systems.  For a description of hydroponic system types, check this page. If you are going to be growing hydroponic marijuana, you need a hydroponic garden.  You can make one yourself by using instructions you can find here.  They are not hard to make and almost any building supply store should have the majority of stuff required. If you would rather buy a unit, it may cost a little more but all parts will be included and you will save time by getting everything at once.  I got an 11 plant unit for $150.00. US.  You can probably find something just as good or better for less money on eBay. If you use eBay or any other source that might leave a paper trail, you might want to have someone else order and have the items shipped to a house other than where the growing will take place.  Be safe, even in areas where weed is tolerated or legal now, it may not be that way in the future.  So don't leave a trail back to yourself.

Lighting

Metal Halide (mh) or High Pressure Sodium (hps) are the lights to get for growing hydroponic marijuana.  If you want to build your own metal halide light fixture, plans are located here. Metal halide light is close to regular room light or cool fluorescent light (blue spectrum) and is best for vegetative (beginning) growth.  While high pressure sodium is in the red end of the spectrum and is best for flowering (later) growth.

You can run

1) either mh or hps light through both stages of growth (good).
2) run a mh light through the veg phase of growth followed by hps light through flowering (very good).
3) run both mh and hps light through all phases of growth (best).

I've found either a single metal halide or high pressure sodium light system works nearly as good as a dual system.  So if you only have one or the other don't worry, it will work just fine. You can't use a standard hps bulb in a mh fixture, but you can use a mh bulb in a hps fixture of the same wattage.  I didn't think this was possible till several months ago when someone I trust told me it was possible.  So I decided to try using a 400 watt mh bulb in a 400 watt hps fixture. The plants are growing as well as they did under the mh bulb in a mh fixture.  The bulb hasn't had to be replaced and the ballast runs as cool as it does with a hps bulb.  When I want to use the hps bulb, I simply remove the mh bulb and replace it with a hps bulb. So if you can only afford or only want a single fixture, I recommend getting a hps fixture and standard mh and hps bulbs rated for the same wattage as your light fixture.  Use the mh bulb for veg growth and the hps for flowering.  There are hps bulbs that can be used in a mh fixture and vice-versa.  But these are special bulbs and cost about double the price of a standard bulb. Bear in mind, you can only use a bulb of the wattage you light system was designed for.  A 400 watt system only uses 400 watt bulbs.  Don't use any other wattage than the one listed on the ballast of your light system.  One exception would be a 430 watt bulb designed for a 400 watt system. There will also be a lamp type specified on you light system (probably on the ballast itself).  My 400 watt metal halide setup specifies an M59/H33 lamp type.  M59/H33 is an ANSI (American National Standards Institute) ballast rating.  M59 is a 400 watt metal halide ballast.  H33 is a 400 watt mercury vapor ballast.  So my light fixture could run a 400 watt metal halide or 400 watt mercury vapor bulb. 400 watts is about the best size of light for growing hydroponic marijuana in a personal garden.  You should be able to grow 4 to 12 plants at a time.  250 watts should be good enough for up to about 2 to 6 plants.  Anything larger (the next standard size is 1000 watts) and you are going to draw a lot of electricity.  Anything smaller will limit the size of your garden to one or two plants, unless you can supplement it with strong sunlight. Expect to pay $150.00 to $500.00 for a 100 to 1000 watt lighting system.  You can get a 400 watt gym type (high-bay or low-bay) light (hps or mh) for about $150.00. While a 400 watt Son-Agro, or other high end grow light system will cost $300.00 or more. I use a 400 watt metal halide gym type light (high bay) on an 11 plant garden, it works fine with 6 to 10 plants.  I usually grow 3 to 6 medium size (18 inches) plants at a time. If you can afford a lighting system made for horticultural purposes with a good reflector and ballast, get it.  It will last longer, allow the light to cover a larger area (more plants), and increase the amount of light individual plants get. You can also find some high-end dual (hps and mh) fixtures.  These dual systems can provide both mh and hps light through both growth phases.  You might want to consider one of these, if you haven't already bought your lighting source yet.  If you can't afford better, a high-bay or low-bay type light will work fine.  I use one. The best source I have found for buying lighting fixtures, bulbs, and other hydroponic equipment at very good prices is eBay.  There is lots of competition and selection.

Seeds Or Clones

If you know someone who grows, ask them for a few clones.  If you don't have access to clones you will have to get seeds.  If you don't already have some, you can ask you friends to save you seeds out of any good weed they may come across. The better the weed is, the better your crop will be.  If the weed the seeds came from was no good, your crop will probably be pretty lousy. If you need seeds, you can get some online.  You can search on one of the search engines listed here.  Use the term marijuana seeds or something similar. Try to find someone that ships their marijuana seeds from the country you live in.  That way, your package does not cross international borders and is less likely to be searched. When buying seeds, don't get the overpriced, exotic ones.  Look for moderately priced, hardy ones like skunk or niagra.  For a descriptions of marijuana strains click here.

Starting Clones

Take your marijuana clone and put it in the grow cup.  Surround the clone with enough media to keep it stationary in its holder.  See the next section for further information on media and placing your seed in the holder. 

Germinate The Seeds

Set up your hydroponic garden before you germinate the seeds.  Make sure everything works fine.  If you are using clones, skip this section unless you need further information on media and placing your seed in the holder. Follow the directions located here to germinate your seeds.  After the seeds have germinated and the root is about a quarter of an inch long, place the seed, root down, on your grow cube or media that is in your hydroponic cups. The standard thing to do is use a rockwool cube to start the seed on and surround it with whatever media you use.  Keep the rockwool cube so that the bottom 70% or so is submerged when the water is at max, but keep the top part above the water so that the seed is never submerged. There are various types of media available to grow in.  Rockwool is one, but there are many others.  Media simply means the substance that the roots grow in.  Since you aren't using soil in a hydroponic garden, you need a substitute. The media will provide no nutrition, it is just a support for the roots.  All nutrition comes from the hydroponic solution.  Do some online searching or refer to whatever book you have about hydroponics if you want to learn more about media used for hydroponic purposes.

Vegetative Marijuana Growth

The first phase of marijuana growth is called the vegetative phase. If you plan on using the mh or hps right away, start with the light about 20 inches or more above the top of the plant and lower the light an inch or so daily until you think the height is right.  Too close and the plants will dry and turn brown.  Too far and the plants grow too tall as they stretch to get closer to their light source. You can also start the vegetative phase with a fluorescent light turned on for 18 to 24 hours a day for the first one or two weeks or longer.  You can use a standard 48 inch fluorescent fixture (with two) 40 watt bulbs placed about 2 to 8 inches above the tops of the plants. 3 to 5 inches is ideal, but you might have to raise the light a bit higher so all the plants get some light, depending on your setup.  Mix your hydroponic nutrient solution to 50% of the normal recommended strength for the first two weeks of growth regardless of lighting. The reason for starting off with fluorescent lighting is to not give the plants too much light at the beginning of the growing process.  Let them build up to it as they would in nature where the seeds would germinate in spring when the sun is not as strong as it will be in summer. An alternative to growing under hps or mh during vegetation is to set up a vegetative area, and a flowering area. The vegetative area would use a cloner or something similar that would allow seeds or clones to grow and two standard 48 inch fluorescent tubes, turned on 24 hours a day. You can build a very good cloner yourself with the instructions found at Overgrow and sometimes you can find a cloner at eBay.  They range in price from $15.00 to $100.00 but are not always available. The flowering area would use a standard hydroponic set up with hps and/or mh fixtures turned on for 12 hours a day. While the flowering plants are going through their cycle with the hydroponic set up, the germinated seeds or clones will have a few months to develop in the cloner.  After the flowering plants have been harvested, the plants in the vegetative area are ready to move to the flowering area.  New seedlings or clones can then be started in the cloner. There are two main benefits to this kind of set up.  Electricity use will be about 25% to 35% less because the mh or hps light is only on 12 hours a day.  The longer a plant has been growing in the vegetative phase, the quicker it will flower. The only drawback I have found is the extra area needed to set up two different grow areas.  Since the flowering plants need absolute darkness during the dark phase, the light from the vegetative area can't reach the flowering plants.  So they need to be isolated, either by using curtains (or something similar) or by being located away from each other.

Start Growing Hydroponic Marijuana

Try to keep the mh or hps light about 12 or more inches above the tops of the plants.  If the parts of the plants closest to the light dry out, raise the height of the light source, they are too close.  If the plants are too far from the light they will stretch and be tall but not have much bud.  That is a waste of space.  Start high and lower the light an inch or two daily until you think the height is right. During the first stage of growth, the vegetative stage, keep the light on 16 to 24 hours a day minimum.  The longer it is on, the faster the plants will grow, but the higher you electricity bill will be.

Marijuana Flowering

Flowering is the phase of marijuana growth that produces the most THC (the active ingredient that produces the high).  Once flowering begins, the height of the plants will taper off as the plant energy is used in the flowering process itself. You can start flowering when the plants are a minimum of about 6 inches high and have at least 4 sets of leaves.  This will take 2 weeks to a month of vegetative growth in most hydroponic gardens.  When you want to start flowering, cut the light back to 12-13 hours a day. The height of the plant will continue to increase for about two to four weeks after flowering has been started, after that all the plants energy will be used for flower production. Limiting the height of a marijuana plant has always been a difficult task for me, so I just raise the height of the light as the plant grows.  There are methods of limiting the height of a plant, but none of them have worked for me, so I'm not going to recommend one, the Marijuana Growers Guide has the most comprehensive descriptions I have seen on limiting the height of weed plants. The flowering cycle lasts about two months, sometimes a little longer, depending on the type of seed.  So the total length of time to raise a crop should be 3 to 4 months in a hydroponic garden. During flowering the dark period must be perfectly dark.  No room light, sun light, or any other light should reach the plant in the 12 hours of darkness that the plant must get everyday.  The strongest light that should reach the plant during flowering would equal that of moonlight. Stronger light than this will delay flowering, and if it continues there is a chance that the plant will not flower, but stay in the vegetative phase. This is more important in the fist 6 weeks of flowering.  When the plants have started to flower for over a month, small amounts of light are not as harmful. You will know the plants are flowering when you see what look like little white hairs developing at bud sites.  They should be visible after about two weeks of the flowering light cycle.  These will eventually be the red hairs that you see on good bud that you have probably smoked in the past or are smoking now.

Nutrients

Plant foods are measured in an N-P-K format.  N(Nitrogen)-P(Phosphorus)-K(Potassium) A 15-15-15 solution contains 15% Nitrogen, 15% Phosphorus, 15% Potassium.  A 20-10-5 solution contains 20% Nitrogen, 10% Phosphorus, 5% Potassium.  The percentage of the solution not used by N-P-K is trace elements and inert material. If you are buying hydroponic nutrient, get the powder kind that mixes with water.  It is much cheaper over the long run when you compare it with already mixed solutions. An all purpose hydroponic nutrient solution 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 depending on the stage of growth, you can adjust different nutrient levels needed at different times to optimize growth. Higher amounts of N are needed when the temperature will be below 80 degrees in the grow room during vegetative growth.  20-20-20, or 23-19-17, or 12-6-6, or something similar, with trace elements should do it. If temperatures are higher than 80 degrees in the grow room, you need not worry about more N in the formula during vegetative growth. During flowering the plant needs lots of P, regardless of temperature.  15-30-15, or 5-20-10, or 2-4-3, or something similar, with trace elements should do it. Do not over fertilize your plants.  If you under fertilize, plants will take longer to grow.  Too much fertilizer will kill your plants.  Follow the mixing instructions on your hydroponic solution package, if you aren't sure, use less rather than more. As water evaporates an is absorbed by the plants, your water reservoir level will drop.  Add tap water that has been aged 3 days or longer to the reservoir.  I don't add nutrient solution when I top up the tank, some people do. Change the nutrient solution every 2 weeks.  That is, discard the old solution and clean out the reservoir, pumps, and other equipment that is used.  Then add tap water that has been aged 3 days or longer to the reservoir then add nutrient solution.  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.

Marijuana Nutrient Cycle

The timer that starts to pump the nutrient solution should turn on and the solution should submerge the plants roots every twenty minutes.  As soon as the roots are submerged, the pump can shut down. If it takes longer than 20 minutes for the cycle to repeat, the roots will usually grow long, And they can grow very long looking for the nutrient solution source. In fact they can grow so long and thick that they prevent the solution from reaching all the way up your grow cups.  This will also raise the chance of root material being ripped out and clogging the system.  Once the flow is clogged by root or other material inside, you will have to take the garden apart and clean it. Check the root length every few weeks.  If it is hard to remove the cups the plants are in because the roots are anchored to the internal channel, the roots are too long.  The root should be short enough to not touch the narrow point where the solution enters the cup holder.  If they are too long, trim them down with scissors.  Make sure they are not going too far, but don't cut unnecessarily.

Harvesting And Curing

Eliminating Marijuana Smell

Growing (and smoking) marijuana will produce odors.  Sometimes they can be strong enough to attract attention.  If you would like to eliminate the smell from growing and/or smoking marijuana the best thing to do is build an ozone generator.

Storing Marijuana

If your weed is going to be stored for more than a year it should be wrapped in an air tight container and be stored somewhere that is dark and cool.  A freezer is best, but a fridge, basement, closet, or something similar will do.  Dry it first if you grow your own, or if the stuff you have is very moist.  And remember that light, air and heat are the things to avoid.