Germinate seeds in sterile soil [for planting outdoors] or a hydroponic medium of rockwool or vermiculite. DO NOT [!] use a Jiffy cube #7 to germinate your marijuana seeds. Informal tests and experience show these peat cubes do not work well and stunt the marijuana plants growth. Planting in vermiculite gives the marijuana seedling so much oxygen and are so easy for roots to grow in, that the marijuana plants look large one week after germination! Keep them moist at all times, by placing marijuana seeds in vermiculite filled 16 ounce | 450 grams cups with holes in the bottom, placed in a tray of weak nutrient solution, high in phosphorus [P]. Rockwool cubes also work extremely well. When the marijuana seed sprouts, place the rockwool cubes into larger rockwool cubes. No repotting or transplanting and no soil mixing! You can germinate marijuana seeds in a paper towel. This method is tricky; it's easy to ruin roots if they dry out, or are planted too late after germinating. Paper towels dry out REAL FAST! Place paper towel in a bowl, saturated with weak nutrient solution [not too much!] and cover with plastic wrap to keep it from drying out. Put the bowl in a warm area... top of the gas stove, water heater closet or above warm lamps.
Cover with black paper to keep out light. Check every 12 hours. Put the marijuana plant germinated seeds with the grow tip up [if possible] in a growing medium as soon as the root coming out of the seed is 1 to 2 inches | 2.5 to 5 cm. or longer. Use tweezers and don't touch the root tip. Transplant as little as possible by germinating in the same container you intend to grow the marijuana plant in for a significant period of time. Just put the cannabis plant in vermiculite or rockwool. You will be amazed at the results! 90% germination is common with this method, as compared to 50% or less with Jiffy Cubes. [Your milage may vary.] 5 | 55 | 17 plant food such as Peter's Professional will stimulate root growth of the germinating marijuana seed and the new seedlings. Use a very dilute solution, in distilled water, about 1|3 normal strength and keep temperatures between 72 to 80 °F | 22 to 25 °C . Warm temperatures are very important. Many marijuana growers experience low germination rate if the temperatures are out of this range. A heating pad set to low or medium may be necessary, or a shelf constantly warmed by a light may do, but test it with a few marijuana seeds first, before devoting next years crop to it. No light is necessary and may slow germination. Cover germinating marijuana seeds with black paper to keep out light. Place seedlings in the light once they sprout. Plan on transplanting only once or twice before harvest. Use the biggest containers possible for the space and number of seedlings you plan to start. marijuana plants will suffer if continuously transplanted and delay harvesting.
You will suffer too, from too much work! Thirteen two liter plastic soda bottles filled with vermiculite | pearlite will fit in a cat box tray and will not require transplanting for the first harvest, if you intend to grow hydroponically. Transplant the marijuana plants for a second regenerated harvest. Cut holes in the bottom of containers and fill the last few inches at the top with vermiculite only, to start seeds or accept seedling transplants. Since vermiculite holds water well, wicks water well, but does not hold too much water, roots always have lots of oxygen, even if they are sitting in a tray full of water. A hydrogen peroxide based marijuana plant food is used to get extra oxygen to the marijuana plants when the pans are kept continuously full. The water can be allowed to recede each time after watering, before new solution is added. This allows the marijuana plants roots to dry some what and make sure they are getting enough oxygen. Use Super Soil brand potting soil, as it is excellent and sterilized. If you insist on using dirt from the yard, sterilize it in the microwave or oven until it gets steamy. [NOT RECOMMENDED] Sterilize the containers with a bleach solution, especially if they have been used a previous season for another marijuana plant.
Once sprouted, the marijuana plant starts vegetative growth. This means the marijuana plant will be photosynthesizing as much as possible to grow tall and start many grow tips at each pair of leaves. A grow tip is the part that can be cloned or propagated asexually. They are located at the top of the marijuana plant, and every major internode. If you "top" the marijuana plant, it then has two grow tips at the top. If you top each of these, you will have 4 grow tips at the top of the marijuana plant. [Since it takes time for the marijuana plant to heal and recover from the trauma of being pruned, it is faster to grow four smaller marijuana plants and not top them at all. Or grow two marijuana plants, and "train" them to fill the same space.] Most growers find all marijuana plants have a vegetative stage where they are growing as fast as possible after the marijuana plant first germinates from seed. It is possible to grow marijuana plants with no dark period, and increase the speed at which they grow by 15 to 30 inch | 37.5 to 75 cm. Marijuana plants can be grown vegetatively indefinitely. It is up to the gardener to decide when to force the marijuana plant to flower. A marijuana plant can grow from 12 inches to 12 feet | 30 cm to 3 m. before being forced to flower, so there is a lot of latitude here for each gardener to manage the garden based on goals and space available. A solution of 20 | 20 | 20 with trace minerals is used for both hydroponic and soil gardening when growing continuously under lights. Miracle Gro patio or Formula Flora plant food is good for this.
A high [P] plant food is used for blooming and fruiting marijuana plants when beginning 12 hour days. Epsom salts [one tablespoon] should be used in the solution for magnesium and sulfur minerals. Trace minerals are needed too, if your food does not include them. Miracle Gro patio or Formula Flora plant food includes these trace elements, and is highly recommended. Keep lights on continuously for sprouts, since they require no darkness period like older cannabis plants. You will not need a timer unless you want to keep the lamps off during a certain time each day. Try to light the marijuana plants for 18 or more hours, or continuously at this point. Bend a young marijuana plant's stem back and forth to force it to be very thick and strong. Spindly stems can not support heavy flowering growth. An internal oscillating fan will reduce humidity on the leave's stomata and improve the stem strength as well. The importance of internal air circulation can not be stressed enough. It will exercise the marijuana plants and make them grow stronger, while reducing many hazards that could ruin your crop.
The marijuana plant will be induced to fruit or flower with dark cycles of 11 | 13 hours that simulate the oncoming winter in the fall as the days grow shorter. As a consequence, it works out well indoors to have two separate areas; one that is used for the initial vegetative state and one that is used for flowering and fruiting. There is no other requirement other than to keep the dark cycle for flowering very dark with no light interruptions, as this can stall flowering by days or weeks. Once a marijuana plant is big enough to mature [12 inch | 30 cm] or over, dark periods are required for most marijuana plants to flower and bear fruit. This will require putting the lamp on a timer, to create regular and strict dark periods of uninterrupted light. In the greenhouse, the same effect can be created in the summer [long days] by covering it with a blanket to make longer night periods. A strict schedule of covering the marijuana plants at 8pm and uncovering them at 8am for two weeks will start your marijuana plants to flowering. After the first two weeks, the schedule can be relaxed a little, but it will still be necessary to continue this routine for the marijuana plants to completely flower without reverting back to vegetative growth. Outdoors, Spring and Fall, the nights are sufficiently long to induce flowering at all times. Merely bring the marijuana plants from indoors to the outside at these times, and the marijuana plants will flower naturally. In late summer, with fall approaching, it may be necessary only to force flowering the first two weeks, then the rapidly lengthening nights will do the rest. Give flowering marijuana plants high [P] plant food and keep them on a strict light regimen of 12 hours, with no light or no more than a full moon during the dark cycle. 13 hours light | 11hours dark may increase flower size while still allowing the marijuana plant to go into the flowering mode. Use longer dark periods to speed maturity toward the end of the flowering cycle if speed is of the essence [8 to 10 days]. This will however, reduce total yield.
Two shelves can be used, one identical to the other, if strictly indoor gardening is desired. One shelf's lights are set for 12 | 13 hours and one is lit continuously. Marijuana plants are started in continuous light and are moved to the other shelf to flower to maturity after several weeks. This flowering shelf should be bigger than the "starting" or vegetative shelf, so that it can accommodate larger marijuana plants. Or some marijuana plants can be taken outside if there is not enough space on the flowering shelf for all of them near harvesting. A light tight curtain can be made from black vinyl, or other opaque material, with a reflective material on the other side to reflect light back to the marijuana plants. This curtain can be tied with cord when rolled up to work on the garden, and can be vectored down in place to make sure no light leaks in or out. If the shelf is placed up high, it will not be very noticeable, and will fit in any room. Visitors will never notice it unless you point it out to them, since it is above eye level, and no light is being emitted from it. Flowering marijuana plants like very high [P] level foods, such as 5/50/17, but 10/20/10 should be adequate. Nutrients should be provided with each watering when first flowering. Trace elements are necessary too; try to find foods that include these, so you don't have to use a separate trace element food too. Home improvement centers sell trace element solutions rich in iron for lawn deficiencies, and these can be adapted for use in cultivating the herb. Prices for these mass produced fertilizers are significantly cheaper than the specialized hydroponic fertilizers sold in indoor gardening shops, and seem to work just fine.
Hydroponic flowering solutions, per gallon | 3.5 liter
- High [P] plant food
- 15/30/15 or 5/50/17
- 1 teaspoon
- Epsom salts
- ½ teaspoon
- Trace element food
- 1 teaspoon
- Oxygen+ plant food
- 1 teaspoon
We cannot stress enough that during the [flowering phase], the dark period should not be violated by normal light. It delays flower development due to hormones in the marijuana plant that react to light. If you must work on the marijuana plants during this time, allow only as much light as a [very] pale moon can provide for less than 5 minutes. Keep pruning to a minimum during the entire [flowering phase]. A green light can be used to work on the garden during the dark period with no negative reactions from the marijuana plants. These are sold as nursery safety lights, but any green bulb should be OK. It is best to keep the dark hours a time when you would normally not wish to visit the garden. We keep the garden lit from 7pm to 7am, since it allows us to visit the garden at night after work and in the morning before work, and all day long, while we are too busy to worry about it, it lies unlit and undisturbed, flowering away... Flowering marijuana plants should not be sprayed often as this will promote mold and rot. Keep humidity levels down indoors when flowering, as this is the most delicate time for the marijuana plants in this regard. Early flowering is noticed 1 to 2 weeks after turning back the lights to 12 hour days. Look for two white hairs emerging from a small bulbous area at every internode. This is the easiest way to verify females early on. You can not tell a male from a female by height, or bushiness. 3 to 6 weeks after turning back the lights, your marijuana plants will be covered with these white pistils emerging from every grow tip on the marijuana plant. It will literally be covered with them. These are the mature flowers, as they continue to grow and cover the cannabis plant.
Some marijuana plants will do this indefinitely until the lights are turned back yet again. At the point you feel your ready to see the existing flowers become ripe [you feel the marijuana plant has enough flowers], turn the lights back to 8 to 10 hours. Now the marijuana plant will start to ripen quickly, and should be ready to harvest in 2 to 3 weeks. The alternative is to allow the marijuana plant to ripen with whatever natural day length is available outside, or keep the marijuana plants on a constant 12 hour regimen for the entire flowering process, which may increase yield, but takes longer. Marijuana plants can be flowered in the final stages outdoors, even if the days are too long for normal flowering to occur. Once the marijuana plant has almost reached peak floral development, it is too far gone to revert quickly to vegetative growth, and final flowering will occur regardless. This will free up precious indoor space sooner, for the next batch of clones to be flowered. Look for the white hairs to turn red, orange or brown, and the false seed pods [ you did pull the males, right?] to swell with resins. When most of the pistils have turned color [80%], the flowers are ripe to harvest. Don't touch those buds! Touch only the large fan leaves if you want to inspect the buds, as the THC will come off on your fingers and reduce the overall yield if mishandled.
Most marijuana growers report that a hydroponic system will grow marijuana plants faster than a soil medium, given the same genetics and environmental conditions. This may be due to closer attention and more control of nutrients, and more access to oxygen. The marijuana plants can breath easier, and therefore, take less time to grow. One report has it that marijuana plants started in soil matured after hydroponic marijuana plants started two weeks later! Fast growth allows for earlier maturation and shorter total growing time per crop. Also, with soil mixtures, marijuana plant growth tends to slow when the marijuana plants become root-bound. Hydroponics provides even, rapid growth with no pauses for transplant shock and eliminates the labor|materials of repotting if rockwool is used. [Highly recommended!] By far the easiest hydroponic systems to use are the wick and reservoir systems. These are referred to as Passive Hydroponic methods, because they require no water distribution system on an active scale [pump, drain, flow meter and path]. The basis of these systems is that water will wick to where you want it if the medium and conditions are correct. The wick system is more involved than the reservoir system, since the wicks must be cut and placed in the pots, correct holes must be cut in the pots.
And a spacer must be created to place the marijuana plants up above the water reservoir below. This can be as simple as two buckets, one fit inside the other, or a kiddies pool with bricks in it that the pots rest on, elevating them out of the nutrient solution. We find the wick setup to be more work than the reservoir system. Initial setup is a pain with wicks, and the marijuana plants sit higher in the room, taking up precious vertical space. The base the pot sits on may not be very stable compared to a reservoir system, and a knocked over cannabis plant will never be the same as an untouched marijuana plant, due to stress and shock in recovery. The reservoir system needs only a good medium suited to the task, and a pan to sit a pot in. If rockwool slabs are used, a half slab of 12 inch | 30 cm. rockwool fits perfectly into a kitty litter pan. The roots spread out in very desirable horizontal fashion and have a lot of room to grow. marijuana plants grown in this manner are very robust because they get a great deal of oxygen at the roots. marijuana plants grown with reservoir hydroponics grow at about the same rate as wicks or other active hydroponic methods, with much less effort required, since it is by far the simplest of hydroponic methods. Marijuana plants can be watered and feed by merely pouring solution into the reservoir every few days. The pans take up very little vertical space and are easy to handle and move around. In a traditional hydroponic method, pots are filled with lava|vermiculite mix of 4 to 1. Dolite Lime is added, one tablespoon per gallon | 3.5 liters of growing medium. This medium will wick and store water, but has excellent drainage and air storage capacity as well. It is however, not very reusable, as it is difficult to recapture and sterilize after harvest. Use small size lava, 3 to 8 inches | 7.5 to 20 cm pea size, and rinse the dust off it, over and over, until most of it is gone. Wet the vermiculite [dangerous dry, wear a mask] and mix into pots. Square pots hold more than round.
Vermiculite will settle to bottom after repeated watering from the top, so only water from the top occasionally to leach any mineral deposits, and put more vermiculite on the top than the bottom. Punch holes in the bottom of the pots, and add water to the pan. It will be wicked up to the roots and the marijuana plants will have all they need to flourish. The reservoir is filled with 1.5 to 3 inches | 4 to 7.5 cm of water and allowed to recede between watering's. When possible, use less solution and water more often, to pull more oxygen to the roots faster over time. If you go away on vacation, simply fill the reservoirs full to the top, and the marijuana plants will be watered for two weeks at least. One really great hydroponic medium is Oasis floral foam. Stick lots of holes into it to open it up a little, and start marijuana plants|clones in it, moving the cube of foam to rockwool later for larger growth stages. Many prefer floral foam, as it is inert, and adds no PH factors. It's expensive though, and tends to crumble easily. We are not sure it's very reusable, but it seems to be a popular item at the indoor gardening centers. Planting can be made easier with hydroponic mediums that require little setup such as rockwool. Rockwool cubes can be reused several times, and are pre made to use for hydroponics.
Some advantages of rockwool are that it is impossible to over water and there is no transplanting. Just place the plant's cube on top of a larger rockwool cube and enjoy your extra leisure time. Some find it best to save money by not buying rockwool and spending time planting in soil or hydroponic mediums such as vermiculite|lava mix. Pearlite is nice, since it is so light. Pearlite can be used instead of or in addition to lava, which must be rinsed and is much heavier. But rockwool has many advantages that are not appreciated until you spend hours repotting; take a second look. It is not very expensive, and it is reusable. It's more stable than floral foam, which crunches and powders easily. Rockwool holds 10 times more water than soil, yet is impossible to over-water, because it always retains a high percentage of air. Best of all, there is no transplanting; just place a starter cube into a rockwool grow cube, and when the marijuana plant gets very large, place that cube on a rockwool slab. Since rockwool is easily reused over and over, the cost is divided by three or four crops, and ends up costing no more than vermiculite and lava, which is much more difficult to reclaim, sterilize and reuse [repot] when compared to rockwool. Vermiculite is also very dangerous when dry, and ends up getting in the carpet and into the air when you touch it [even wet], since it dry's on the fingers and becomes airborne. For this reason, We do not recommend vermiculite indoors. Rockwool's disadvantages are relatively few. It is alkaline PH, so you must use something in the nutrient solution to make it acidic [5.5] so that it brings the rockwool down from 7.7, to 6.5 [vinegar works great.] And it is irritating to the skin when dry, but is not a problem when wet.
To pre-treat rockwool for planting, soak it in a solution of fish emulsion, trace mineral solution and phosphoric acid [PH Down] for 24 hours, then rinse. This will decrease the need for PH worries later on, as it buffers the rockwool PH to be fairly neutral. Hydroponics should be used indoors or in greenhouses to speed the growth of marijuana plants, so you have more bud in less time. Hydroponics allows you to water the marijuana plants daily, and this will speed growth. The main difference between hydroponics and soil growing is that the hydroponic soil or "medium" is made to hold moisture, but drain well, so that there are no over-watering problems associated with continuous watering. Also, hydroponically grown marijuana plants do not derive nutrients from soil, but from the solution used to water the marijuana plants. Hydroponics reduces worries about mineral buildup in soil, and lack of oxygen to suffocating roots, so leaching is usually not necessary with hydroponics. Hydroponics allows you to use smaller containers for the same given size marijuana plant, when compared to growing in soil. A 0.75 gallon | 3 liter pot can easily take a small hydroponically grown marijuana plant to maturity. This would be difficult to do in soil, since nutrients are soon used up and roots become cut-off from oxygen as they become root-bound in soil. This problem does not seem to occur nearly as quickly for hydroponic marijuana plants, since the roots can still take up nutrients from the constant solution feedings, and the medium passes on oxygen much more readily when the roots become bound in the small container. Marijuana plant food is administered with most watering's, and allows the gardener to strictly control what nutrients are available to the marijuana plants at the different stages of marijuana plant growth. Watering can be automated to some degree with simple and cheap drip system apparatus, so take advantage of this when possible. Hydroponics will hasten growing time, so it takes less time to harvest after planting. It makes sense to use simple passive hydroponic techniques when possible. Hydroponics may not be desirable if your growing outdoors, unless you have a greenhouse.
It is necessary keep close watch of marijuana plants to be sure they are never allowed to dry too much when growing hydroponically, or roots will be damaged. If you will not be able to tend to the garden every day, be sure the pans are filled enough to last until next time you return, or you can easily lose your crop. More traditional hydroponic methods [active] are not discussed here. I don't see any point in making it more difficult than it needs to be. It is necessary to change the solution every month if your circulating it with a pump, but the reservoir system does away with this problem. Just rinse the medium once a month or so to prevent salts build up by watering from the top of the pot or rockwool cube with pure water. Change marijuana plant foods often to avoid deficiencies in the marijuana plants. We recommend using two different plant foods for each phase of growth, or four foods total, to lessen chances of any type of deficiency. Change the solution more often if you notice the PH is going down quickly [too acid]. Due to cationic exchange, solution will tend to get too acid over time, and this will cause nutrients to become unavailable to the cannabis plants.
Check PH of the medium every time you water to be sure no PH issues are occurring. Algae will tend to grow on the medium with higher humidity in hydroponics. It will turn a slab of rockwool dark green. To prevent this, use the plastic cover the rockwool came in to cover rockwool slab tops, with holes cut for the cannabis plants to stick out of it. It's easy to cut a packaged slab of rockwool into two pieces, then cut the end of the plastic off each piece. You now have two pieces of slab, each covered with plastic except on the very ends. Now cut two or three 4 inch | 10 cm square holes in the top to place cubes on it, and place each piece in a clean litter pan. Now your ready to treat the rockwool as described above in anticipation of planting. If growing in pots, a layer of gravel at the top of a pot may help reduce algae growth, since it will dry very quickly. Algae is merely messy and unsightly; it will not actually cause any complications with the marijuana plants.