The cannabis grow cycle is generally divided into three stages: the clone/seed stage, the vegetative stage, and the flowering/budding stage. In order to maximize their return on investment, many indoor cannabis growers implement a gardening method known as perpetual gardening. When practicing perpetual gardening, a plant is immediately replaced as soon as it is harvested or moved into the flowering or vegetative stage; thus creating a perpetual garden cycle.
For example, when plants are harvested from the flowering room, they are immediately replaced with ready-to-flower plants from the vegetative area. The vegetative plants that were moved into the flowering stage are then immediately replaced with rooted clones from the cloning area. And, finally, the rooted clones that were moved to the vegetative stage are replaced with new cuttings. All that is required for a perpetual garden set-up are dedicated areas for each stage of growth and a little experimentation to calculate the timing of both the harvest and the replacement plants. Each growing stage in a perpetual garden relies on the stage before it. The efficiency and effectiveness of a perpetual garden is no joke, but, as with comedy, timing is everything.
Although they rely on the same principle of continual plant replacement, not all perpetual gardens are the same. The two most common perpetual garden techniques used by indoor cannabis horticulturists are the continual harvest technique and the entire flowering room replacement technique. For both, the grower must accurately time out the cloning and vegetative grow cycles to coordinate with the harvest. The continual harvest technique is a good fit for most novice or hobby growers. Commercial growers and more experienced hobbyists may opt for the entire flowering room replacement technique.
The continual harvest technique is a type of perpetual gardening where the horticulturist is harvesting a portion of the flowering room on a weekly, bi-weekly, or monthly basis. In other words, the grower is not harvesting all the plants in the flowering room at once, but, instead, is harvesting a portion of the plants in the flowering room. A continual harvest flowering room will have multiple plants that are in different stages of flowering growth. For example, say a grower has 16 plants and wants to harvest two plants per week. This grower would rotate two plants into his or her flowering room every week. By the end of the eight week (on average) flowering period, the grower would have two plants representing each week of the flowering cycle (two plants in the first week of flowering, two plants in the second week of flowering, and so on). After eight weeks in the flowering room, the first two plants would be ready for harvest. Once the first two plants that were cycled into the rotation are harvested, the grower can expect to harvest two plants per week as long as he or she continues to replace the plants with ready-to-flower vegetative plants.
The timing for a continual harvest perpetual garden is fairly straightforward, which is why it’s a great perpetual gardening technique for novice growers and hobbyists. To stay on schedule, a grower needs to take new cuttings every week, two weeks, or month, depending on how often he or she would like to harvest. Sticking with our previous example, if the grower wants to harvest every week, then he or she would need to take new cuttings every week. Having more clones and vegetative plants than will be needed is always a good idea for a perpetual cannabis gardener. This allows some leeway for mistakes or timing issues and also provides the grower with the opportunity to cycle the very best plants into the next stage of growth. Put another way, if the grower only needs to cycle two plants into the next stage, but he or she has more than two plants ready, he or she can choose the healthiest, most vigorous plants.
As in the cloning stage, having more plants in the vegetative stage than needed will only be advantageous. Timing the vegetative stage can be tricky in any cannabis garden. That’s because there is no right answer as to how long to leave a cannabis plant in vegetative growth. What needs to be remembered is that a cannabis plant will finish at about twice the size it was when it first started the flowering stage. In other words, a 12 inch vegetative plant moved into the flowering room will finish at roughly 24 inches. The main limiting factor over the duration of vegetative growth is the size of the flowering area and what size plants it can handle. The good news for novice cannabis growers is that a cannabis plant can be pruned or manipulated to limit its size. In a continual harvest perpetual garden, a grower can control the size of the vegetative plants with pruning techniques or, if the plants are growing too large for the flowering room, adjust the timing of the rotation so the vegetative plants start later. However, the simplest and most straightforward way is to stick to the given duration (in our example, one week) and use pruning or manipulation to achieve the size required by the flowering area.
The biggest advantage of a continual harvest garden is that the work load of the harvest is spread out evenly. Also, because a gardener is harvesting more often, he or she gets to enjoy the fruits of his or her labor more regularly. Some disadvantages of a continual harvest garden are maintaining the various feeding regimens for the plants in all the different stages of flowering. This type of gardening technique does not allow the horticulturist to link plants together in a recirculating hydroponic system (due to the varying nutritional needs). However, the biggest disadvantage is the inability to treat pest insects or pathogens (due to some plants always being in the later stages of flowering). If a pest insect or pathogen appears, eradicating it can be more difficult because the flowering room contains plants in all stages of flowering. Treating plants in the later stages of flowering with any foliar spray or chemical pesticide is a big no-no.
The other perpetual gardening technique used by cannabis cultivators is the entire flowering room replacement technique. With this system, the grower harvests all the plants in the flowering room at once and then replaces all of those plants with plants from the vegetative area. Similar to the continual harvest technique, timing the vegetative period can get tricky and will vary from room to room. To have enough ready-to-flower vegetative plants waiting to be cycled into the next stage, they must be given enough time to grow. That being said, if the plants are left in the vegetative area too long, they can become overgrown, root bound, or otherwise stressed in a way that could hinder their performance in the flowering room. As with the continual harvest technique, some pruning and plant manipulation can be used in the vegetative stage to ensure the plants are the right size for flowering. However, the better the timing, the less a grower will have to rely on pruning the vegetative plants down to size.
When a gardener first starts out employing a perpetual growing technique, he or she should pay close attention to the amount of time it takes his or her particular variety to grow to the desired size for flowering (and later exactly how long it takes to reach maturity in flowering). When the goal is to harvest large, monster plants, cannabis growers will keep their plants in vegetative growth for anywhere from four to eight weeks. When the goal is to harvest multiple small plants, such as in a sea-of-green-style garden, the grower might only leave their plants in vegetative growth for a couple of weeks. Once the desired vegetative duration is determined, a horticulturist can add two weeks (for cloning) to figure out when the clones need to be started for the next cycle. For example, say a grower chooses a cannabis strain that takes exactly eight weeks to reach maturity in flowering. It takes this same variety four weeks of vegetative growth to reach the desired size for flowering. When two weeks for cloning are added on to the four weeks for vegetative growth, the total is six weeks. This means a grower should start the cutting/cloning process six weeks prior to harvest or after the flowering crop is two weeks into the cycle.
The biggest advantages of entire flowering room replacement are the ability to use uniform feeding regimens for all the plants in the flowering room, the ability to treat pest insects and pathogens more effectively, and the ability to run high-performance recirculating hydroponic systems. Harvesting the entire flowering room also allows the grower to do a deep cleaning and complete sterilization of the room prior to bringing in the next batch of plants. This can be viewed as an increase in preventative maintenance. Disadvantages of the entire flowering room replacement technique include a larger workload around harvest time, more finicky timing issues, and, although the yields are larger, longer periods between harvests.
In order to maximize efficiency and, in turn, their return on investment, indoor cannabis horticulturists should implement some sort of perpetual gardening technique. Unfortunately, there is no one right answer pertaining to the timing or particular technique that will work best for all growers. All gardens are unique, which means a little experimentation is necessary to determine the ideal timing and techniques a grower should use to maximize his or her cannabis garden’s potential.
Eric Hopper is the Editor in Chief for NUGL Media. He can be contacted at firstname.lastname@example.org.