Your Guide to the Perpetual Harvest: UPDATED

Columns - Tomorrow in Cannabis

35 easy steps to help you master the symbiotic rotation process.

January 23, 2020

Pruning the bottom branches for a rotation garden.
Photo by Mel Frank; Courtesy Green Candy Press

This excerpt from “Marijuana Horticulture Fundamentals: A Comprehensive Guide to Cannabis Cultivation and Hashish Production” (Green Candy Press), by Ken Morrow, has been reprinted (and edited for space) with permission. You may purchase the complete book at

Symbiotic rotation is essentially the practice of having all stages of your plants ready exactly when you need them. On the day of harvest, vegetative plants must be ready to install in the flowering room, and your clones must be ready to be moved to the vegetative room. After cleanup and decontamination, the clone room should be ready for more clones, taken from the plants in the flowering room. Empty space is a waste of time [and money].

For all practical purposes, you don’t want plants ready before or after they are needed, but exactly when you want them—thus creating a symbiotic rotation. Refining the variables is key. Catering to the plant’s every need is the first priority. Second is maximizing its full potential.

Choosing a Cultivar

Understanding the parameters and limitations of your chosen cultivar is also paramount. You must experiment and investigate all possibilities and options. All plants are different. Here we discuss the two basic cultivars and their strengths and weaknesses in regard to symbiotic rotation.

Cannabis Sativa

Cannabis sativa typically grows tall and lanky with long internodal spacing, creating long, airy buds. They grow too tall for most indoor situations and take far longer to finish flowering than cannabis indica; sativa can take 8 to 16-plus weeks to finish!

The symbiotic rotation style is more labor-intensive if you are growing cannabis sativa. It can be done, but you must skip a vegetative cycle, meaning your flowering sativa plants won’t be finished for (probably) 12 weeks or more, so you will have a quandary!

The way to overcome this situation is to eliminate your vegetative plants after you’ve taken clones. Wait for clones to root, then install them in the vegetative room. By eliminating the previous vegetative cycle, you have allowed the slow-flowering sativa to finish flowering, but still have vegetative plants and clones ready exactly when you want them. Essentially, you are skipping a cycle to wait for the sativa to finish flowering.

Cannabis Indica

Cannabis indica and cannabis indica/sativa hybrids are perfect adaptations, and so adapt to a symbiotic rotation flawlessly. Starting from seed or clone, you will grow your plants to approximately 10 to 12 inches tall, depending

on your chosen genetics/cultivar and internodal length. The plants will have many branches available for clones. Strip the donor plants of all available clones and place donor plants in the flowering room. Clones can take from 7 to 21 days to root depending on environmental conditions and genetics/cultivar. Ideally, you want the plants to finish at approximately 24 to 36 inches tall, so you will induce flowering when plants are approximately 12 to 18 inches tall. So, if you take clones (which take 14 days) and you then vegetate for 14 days, you will have both ready before your other plants have finished flowering. This would create a problem.

Symbiotic Rotation Timeline

In this scenario, the grower needs four rooms/chambers/areas: one for clones, one for vegetation, and two rotating flowering areas:

Area 1: Clone area

Area 2: Vegetative area

Area 3: Flowering area

Area 4: Flowering area

(Areas 3 and 4 are also used for vegetative growth and for producing more available clone material.) The rooms/chambers/areas can be … part of a room sectioned off. For simplicity’s sake, I’ll call them simply “areas.”

Step 1. Start with eight plants from the same cultivar. Grow plants to approximately 12 inches tall and completely strip off any clones. (This process can yield about six to eight clones per plant; about 48 to 56 total.) Allow 14 days to root each clone.

Step 2. After the clones have rooted thoroughly, 14 days later, install the rooted clones into the Area 2 vegetative areas with 18 hours of light.

Step 3. Seven days after installation of the clones, clean plants up. Remove all lower leaves and vegetation to allow the plants to concentrate all available energy into developing the next batch of available clones. Remove unhealthy leaves. Only healthy clone stock is left on the 6- to 8-inch plants.

Step 4. Twenty-two days later, again strip and remove all available clones and eliminate the donors. (This time, you could get up to 400 clones from 64 plants.) Fifty percent of these will later be eliminated; only the best are kept and installed into the vegetation area.

Step 5. Move the remaining half of the plants into the Area 2 vegetative room with 18 hours of light. Take only the best plants, and dispose of the other half. This ensures that you only grow the best plants.

Step 6. Clean off all the unhealthy leaves and unwanted lower branches, as in Step 3 above.

Step 7. Twelve days later, transfer vegetative plants to the stage three flowering areas. Put the best one-quarter of the best plants in each room. Keep the lights on at the 18-hour cycle. Dispose of the leftover half of the plants. (In one example, 50 plants were placed in each flowering room and 100 plants were discarded.)

Step 8. Two days later, turn flower area one into a 12/12 light cycle. Area 2 remains 18/6.

Step 9. Two days later, take clones from plants in Areas 1 and 2. The plants in Area 4 are topped (the tips taken off to prevent the plant from getting too tall) and only a few branches are left on them while the plants in flowering room 4 are allowed to finish flowering. Light schedules in Areas 1 and 2 remain the same (i.e., Area 1 at 12/12 light cycle and Area 2 at 18/6).

Step 10. Twenty-one days later, turn flowering Area 4 to a 12/12 light cycle.

Two rooms showing different stages of plant development.
Photo by Freebie; Courtesy Green Candy Press

Step 11. One day later, transfer rooted clones to Area 2.

Step 12. Vegetative plants in Area 2 should be grown to approximately 12 inches tall and ... stripped of all available clones. ... However, leave plenty of viable material to finish flowering.

Step 13. Eleven days later, turn the lights in Area 3 to 10 hours on/14 hours off and significantly lower the ammonium and nitrate nitrogen (nutrient) levels. Eliminate all ammonium nitrate by the end of the growth cycle. (This is the N in the NPK ratio, or the vegetative component in nutrients.)

Step 14. Six days later, clean up/strip Area 2 (the vegetative room). Remove the lower leaves and vegetation, as well as any unhealthy leaves and material unsuitable for clones, as in Step 3.

Step 15. Eight days later, harvest all plants from flowering Area 3; clean and decontaminate the room in preparation for re-installation.

Step 16. One day later, transfer Area 2 vegetative plants to the empty flowering area, changing the light schedule to 12/12. Transfer all Area 1 clones to the vegetative Area 2. All of this should be done only after a thorough cleaning and decontamination of all empty rooms and systems.

Step 17. Two days later, take the clones from flowering Area 3 that have been on 12/12 cycle for 2 days and place them in Area 1 for rooting.

Step 18. Fourteen days later, strip/clean up stage two vegetative room. Clean off any and all unwanted/unhealthy material, as in Step 3.

Step 19. Seven days later, harvest flowering room two, immediately clean and decontaminate the area in preparation for re-installation, and transfer stage two vegetative plants from Area 2 to flowering Area 4.

Step 20. One day later, transfer Area 1 clones to Area 2; turn light to a 12/12 cycle.

Be sure to stake your plants at an appropriate time so they are prepared for flowering.
Photo by Freebie; Courtesy Green Candy Press;

Step 21. Two days later, take clones from flowering Area 4.

Step 22. Eighteen days later, clean up/strip vegetative Area 2.

Step 23. Four days later, harvest flowering Area 1.

Step 24. Two days later, take clones from flowering Area 1

Step 25. Sixteen days later, clean up/strip vegetative Area 2 of any unwanted/unusable material.

Step 26. Six days later, harvest Area 4, transfer Area 2 vegetative to Area 4 flowering, and turn lights to 12/12.

Step 27. One day later, transfer Area 1 clones to Area 2 vegetative area.

Step 28. One day later, take clones from flowering Area 2.

Step 29. Twenty days later, clean up/strip Area 2 veg of unwanted/unusable material.

Step 30. Four days later, harvest flowering Area 3 and transfer area 2 vegetative to flowering Area 3, leaving the lights at 18/6.

Step 31. One day later, turn flowering Area 3’s light cycle to 12/12.

Step 32. Two days later, clean up/strip Area 2 vegetative of any unwanted/unusable material.

Step 33. Fourteen days later, clean up/strip Area 2.

Step 34. Seven days later, harvest flowering Area 4 and transfer Area 2 vegetative to flowering Area 4. Transfer Area 1 clones to Area 2 vegetative area.

Step 35. Two days later, take clones from Area 2. Repeat this scheduling process over and over again—it is cyclical.

Every step of this schedule was dictated by growing methodologies, environmental conditions and genetics. We used four different cultivars, all indica/sativa hybrids, yet each rooted at different times. Each had a different growth rate and pattern, and each finished/matured at slightly different rates.

All of these factors must be considered when creating a working symbiotic rotation. The same symbiotic rotation cycle can be used for three-room rotations or by using mother plants instead of constantly rotating clones and vegetative plants, but in my experience, the above schedule is much more efficient than any other method, period!

Kenneth Morrow has been writing cannabis-related articles and books for more than 20 years. He owns Trichome Technologies, a cannabis R&D company. Morrow also is an award-winning grower and breeder. Has made contributions to many of today's extraction methodologies and holds multiple patents. He consults on all cannabis-related subjects. Find him on Facebook at: Trichome Technologies or Instagram: TrichomeTechnologies.