Ultimate Guide On How To Maintain A Perpetual Harvest

09 January 2023
If you never want to run out of weed, a perpetual harvest is the best way to maintain a steady supply!
09 January 2023
36 min read
Ultimate Guide On How To Maintain A Perpetual Harvest

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  • 1. What is a perpetual harvest?
  • 2. What’s the cost of a perpetual harvest?
  • 3. Pros and cons
  • 4. Strain and timing
  • 5. Perpetual harvest with autoflowering strains
  • 6. Vegetative and flowering growing spaces
  • 6. a. Recommendations
  • 7. Perpetual harvest step-by-step
  • 7. a. Step 1: seeds or clones
  • 7. b. Step 2: let them vegetate
  • 7. c. Step 3: move them to the flowering tent
  • 7. d. Step 4: harvest and repeat
  • 8. Autoflower perpetual harvest schedule
  • 9. Perpetual harvest faqs
  • 10. In conclusion

A perpetual harvest, also known as symbiotic rotation, is a method mostly used by commercial cannabis seeds growers or avid smokers who don’t want to run out of cannabis and need a fixed harvest.

1. What is a perpetual harvest?

A perpetual harvest consists of having different grow tents containing plants in all stages, this way you never run out of buds because you’ll harvest plants on a schedule and have other plants ready to move and substitute the ones you've just harvested.

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This technique uses multiple grow tents to make sure you have plants in the vegetative and flowering stage at all times with one tent running an 18/6 and the other one running a 12/12 light cycle.

Have in mind that almost every grower that does starts from clones that they took from their plants in the vegetative stage, this will allow you to save money on seeds but you will be stuck with the same strain, you can also start from seed but it can get expensive, either way after your plants are in the vegetative stage, the process is the same. Once your vegetative plants reach a certain height you can move them to the 12/12 tent or if your flowering plants are ready for harvest, you can move them from the 18/6 tent into the flowering tent.

2. What’s the cost of a perpetual harvest?

This method itself doesn’t require any special equipment but because you need two or more growing tents, you’ll have to double up on all equipment (like light, exhaust fan, fans) and that’s not all.


How To Maintain A Perpetual Harvest: multiple grow tents

You need multiple grow tents to mantain a perpetual harvest with photoperiodic cannabis.

Because you have to maintain a temperature and humidity level, the electricity bill can go up, but it’s worth it if you are a commercial grower or if you benefit from the insane amounts of buds you’ll harvest.

3. Pros and cons


Scheduled harvest

Depending on the strains, plant size and number of grow tents, you can schedule your harvest from every couple of weeks to every couple of months

By knowing when you’re going to harvest you can set up and prepare your drying room and even schedule your harvest for a weekend so you’re able to trim every plant with no hurry.

High yields

Because you’re growing in a couple of tents, you’ll have a lot of plants to harvest at a time and the yields will be huge.

Never run out of weed

With a perpetual harvest, you’ll never run out of weed and even if you do (which is really hard), you’ll probably have a harvest coming up soon so there’s no need to spend money buying flowers.


How To Maintain A Perpetual Harvest: pros and cons

Pros and cons of maintaining a perpetual harvest.


High cost

With more grow tents and growing equipment the cost will go up considerably, although it’s worth it for commercial growers, you’ll have to evaluate it if you’re a home grower.

Needs more space

The amount of space needed will depend on the number of plants you want to harvest at a time but either way, it will take more space than having just one, usually, growers use 2-3 growing tents so you’ll need a big room.

A lot of plants and weed

This is not actually a con per se but if you live in a place where cannabis is illegal it definitely is depending on the country, you can get in trouble with the police if you have professional growing equipment and a large amount of plants and cannabis.

4. Strain and timing

A big factor that will influence your harvest schedule is the strains you’ll be growing.  Photoperiodic strains may take 8-13 weeks from seed to harvest so having approximately when your harvest is gonna be is crucial, normally, you would grow just one strain at a time and how long it takes to flower would be your schedule. In general, perpetual harvest setups work best with pure Indica and Indica dominant hybrid strains. This is due to the fact that Indica dominant strains have a tendency to grow in a more compact way, and have shorter flowering periods than their Sativa counterparts.

This compacted growth helps with plant management during the flowering stage. It's also beneficial to understand the specific lifecycle timing for each strain you are considering to grow in your perpetual harvest setup. Every seed comes with a growing guide, but there are some inherent variations with each seed so it's best to grow a few first and keep a detailed grow log to better understand each specific phenotype and cultivar. So, for example, if your seeds take 10 weeks to flower you know you’re going to harvest in 10 weeks but if you grow more than one it can be hard to control, another good way is to have one strain per tent, so you have one strain flowering and another one vegetating to make it easier to keep track.

5. Perpetual harvest with autoflowering strains

If you want to spend less money and time or maybe learn how it works before investing in more equipment, you can have a perpetual harvest with autoflowering cannabis plants, because you don’t need to change the light cycle you can do this with just one growing tent.


How To Maintain A Perpetual Harvest: perpetual harvesting autos

When perpetual harvesting autos you can do it with just one tent.

This is because autos vegetate and flower under the same light cycle (18/6) so you can have plants in all stages in the same tent, the down side is you’ll have to germinate seeds every time you harvest.

When growing autos this way, the problem isn’t coordinating when you’ll move the plants to the flowering tent but controlling the height, because autoflowering cannabis are hybrids they can be Sativa or Indica-dominant and their structure and height will vary a lot so you’ll have to train them either with a trellis net like a Scrog or by tying down the branches so all of them receive the same amount of light.

Always be sure to take maximum care when doing any sort of stress training with autos. Stress training can lead to a decrease in veg growth for up to a week while the plant recovers. This is less of a problem for photoperiod plants as you can just extend their veg time. Autoflowering cannabis plants have a genetic inbuilt timer that “automatically” switches the plant from the veg growth stage to the flowering stage, which in turn means the plant has less time to recover from any stress it is put under. 

6. Vegetative and flowering growing spaces

When you’re setting up the growing spaces for a perpetual harvest you need at least 2 growing tents (unless you’re growing autoflowering strains), each one of them must have an optimal environment for the stage the plants are in.

The vegetative tent must have a higher humidity (around 60%) and an 18/6 light cycle with a blue light spectrum while the flowering tent must have a relative humidity of around 45% and a 12/12 light cycle with a red spectrum.



Vegetative grow tent Flowering grow tent
To shorten the veg. Stage, grow smaller plants. Make sure your tent is light-proof, if there are light leaks they can become hermaphrodites.
It’s recommended you have one strain per grow tent to avoid problems. Have a carbon filter ready, a large number of plants will smell up the whole room.
Use weaker lights than in the flowering tent. Ensure you control the temperature and humidity to prevent getting bugs or mold. in the buds.

Recommendations for the vegetative and flowering growing spaces.

Because you don’t need more than one tent when growing autoflowers, you will have to adjust the environment in your grow tent as your autos grow, have in mind the appropriate temperature and humidity can vary from strain to strain but you can use the same as for photoperiodic cannabis and adjust accordingly.

7. Perpetual harvest step-by-step

After you have your growing spaces set up you just need to start growing, by following these simple steps you can successfully run a perpetual harvest without hassle.

Step 1: Seeds or clones

First of all, you need plants. You can start a perpetual harvest with seeds or clones, starting from clones will take less time and will save you around 2-3 weeks, but if you don’t have a way to get clones you’ll just have to germinate the desired number of seeds. Using clones and sourcing all of your plants from a single mother plant can make life easier than growing from seed. Even if you start with the same seed, there can be slight variations in timing due to differences between strain phenotypes. Using clones from a single mother plant ensures zero genetic differences and ensures your plants grow at the exact same rate, as long as they are kept under the same conditions.

How To Maintain A Perpetual Harvest: taking clones

You can take up 50 clones or more from a single cannabis plants.

Step 2: Let them vegetate

Although it’s not obligatory, it’s recommended you have one strain per tent, this way you avoid having problems, if you are vegetating different strains in the same tent, some may grow taller and overshadow the smaller ones, and you’ll have to train them.

Having the same strain means you’ll transfer all of them to the flowering tent at the same time instead of having to move one by one when they’re ready.

Step 3: Move them to the flowering tent

After your plants have reached the desired height, you can move them to the flowering tent, make sure you have plants to move into the veg. Tent also.

If this isn’t your first growing cycle, this is when you’ll be harvesting the plants in the flowering tent but if it’s the first you don’t have to worry about that.

It’s extremely important to clean your tents before moving your plants.

Step 4: Harvest and repeat

After your first harvest, you’ll have everything ready to continue your perpetual harvest. 

When you harvest your plants, you’ll transfer more plants from the veg. tent to the flowering tent and you’ll have clones or germinated seeds ready to move into the veg. tent.


How To Maintain A Perpetual Harvest: harvesting

When your plants are ready, you can harvest them and repeat the process.

All you have to do now is keep moving plants from one tent to another when they’re ready and keep harvesting forever.

8. Autoflower Perpetual Harvest Schedule

Thanks to the genetic timer hardcoded in autos it is straightforward and simple to create a perpetual harvest schedule that will allow you to grow a never-ending supply of dank nugs. A basic timetable that works great for autos is as follows. First up, plant your seeds and let them grow out to the end of the vegetative stage. As soon as this first set of plants starts to flower it's time to start your next set of seeds. This can be done in the same grow tent or room as your original plants, or you can set up a dedicated seedling grow space.

When it comes time to harvest your first set of plants, your second set should be in the early stages of flowering growth. Simply plant another round of seeds and you have successfully set up a perpetual growth cycle. All you have to do from this point is to plant another set of seeds each time you harvest a previous set of plants!

9. Perpetual Harvest FAQs

So there you have it, our complete rundown on why we think every indoor cannabis home grower should look at running a perpetual harvest routine. But no matter how in-depth we dive, there are always going to be some lingering questions - especially when it comes to setting up your first perpetual harvest routine. Let's run through the most common queries, and see if we can lay out some simple and easy-to-understand answers!

What works better for perpetual harvesting - photoperiodic or autoflowering strains?

There's no one right answer to this question, as there are a bunch of factors that need to be taken into consideration. The size of the grow space, how many different grow spaces are available, and the type of strains you personally enjoy growing all need to be thought through before making any decision.

But if you are looking to set up your first perpetual harvest routine, and want to keep things as simple as possible, then you really can't beat autos. In the past decade, autoflowering genetics have gone through a true renaissance, to the point where they can now compete with the very best that photoperiods have to offer.

These days both hobby and commercial growers alike are switching over to autoflowering strains as their main cash crop, and nowhere is that more true than with perpetual harvest situations. One of the huge benefits of autos is the fact that, unlike photos, they can go all the way from seed to harvest under the same lighting regime. They are also super hardy, and very resistant to certain stressors that can negatively affect traditional marijuana crops. Even if you have just one small grow tent, there is nothing stopping you from setting up a perpetual grow with autos. And autoflowers also provide much faster harvests than photos do, meaning you can get through more crops at the same time! So, to answer the question, it's hard to beat autoflowering strains when it comes to perpetual harvesting. They are more forgiving, easier to work with, and often provide bigger yields and faster harvests under much less demanding lighting conditions.

What sized grow tent works best for a perpetual harvest routine?

When it comes to perpetual harvesting, bigger is better. The bare minimum we would recommend is a 4 x 4 foot (1.2 x 1.2 meter) size, as this is large enough for about 5 fully grown plants. But honestly, if you can go a little bit bigger then you're definitely not going to regret it.

As you slowly dip your toes into cannabis cultivation, and into perpetual harvesting in particular, you're going to pretty quickly want an extra grow tent (or two!). One thing to keep in mind is that if you are running the whole crop in one tent, the older plants may cause some shading issues for the younger ones if the tent is cramped. There are a few workarounds for this, from adding extra light to tieing the larger plants back, to raising the younger ones up so the canopy is all one height.

Which autoflowering strains work best with perpetual harvesting?

Again, that's really up to you. One thing to keep in mind is that each and every strain will take a different length of time to go from seed to harvest, so with perpetual harvesting it's usually best to stick to just one or two strains. Look, if you have a bunch of room in your tent then go wild! There are not many aspects to cannabis cultivation that are more fun than playing around with a bunch of strains at the same time, but doing so does increase the amount of work you will have to put in, and it also increases the space needed for perpetual harvesting. Our top strains to run in a perpetual harvest are Gorilla Cookies Auto, Banana Purple Punch Auto, and Bruce Banner Auto. All three of these top-shelf strains offer huge yield potential with ridiculous resin production. But really, choose whatever takes your fancy.

Which growing medium is best suited to perpetual harvesting?

Pretty much any growing medium can be used for autoflowering plants, but we particularly like using coco coir. It's pH stable, easy to work with, and can really give autoflowering plants the extra kick they need to reach their full potential. It's also super forgiving if any nutrient issues pop up, and offers a bunch of the advantages from both soil and hydro with almost none of the drawbacks.

10. In conclusion

Perpetual harvest is the best way to keep your jars always full if you smoke too much or if you’re a commercial grower and despite being more world because of the number of plants, it’s worth it.

We hope this article helps you start your own never-ending harvest and if you are already running a perpetual harvest tell us how it’s going, please leave us a comment below!

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