by Nebula Haze
A cannabis grower must grow enough weed to never run out. Otherwise, what’s the point? How do you ensure you harvest as much weed as you need?
The answer is to always be harvesting. (Of course, it also helps to grow a lot of cannabis at once).
This article shows you how to grow a cannabis perpetual harvest, so you can harvest a new batch of weed every 1-2 months and never run out again.
Harvest new weed every few months with the “Perpetual Harvest” cannabis technique.
Cannabis Perpetual Harvest: 2 Main Strategies
- Method 1: Multiple grow spaces (harvest every ~2 months) – Keep vegetative plants and seedlings in one small grow space, and set up a separate bigger grow space for flowering plants while they make buds. After every harvest, move the vegetative plants into the flowering space and start a new set of seedlings in the vegetative space. This setup allows you to harvest about once every 2 months as long as you follow the instructions below.
- Method 2: Auto-flowering strains in intervals (harvest as often as you want) – Since auto-flowering strains make flowers automatically, you can plant a new seed as often as needed and keep the plants right next to each other. Their buds will form on their own and be ready to harvest 2-3 months from germination. This allows you to harvest buds as frequently as you want (every month, every week, etc.) without needing more than one grow space.
This harvest produced over 1 lb of premium cannabis buds plus a bag of trim to turn into goodies. If you use a 4’x4′ grow tent with 600W grow light (Example 600W LED setup or 600W HPS setup) for your flowering grow space in this tutorial, you can easily harvest this much weed about once every 2 months.
Let’s get into it!
Method 1: Multiple Grow Spaces (Separate vegetative and flowering grow space)
In this method, you will set up a separate vegetative and flowering grow space for your cannabis plants. Essentially you will grow plants in the vegetative grow space until they’ve reached about half their final height, which takes about 2 months on average. Then you will move them to the flowering grow space to make buds, using strains that take about 2 months before buds are ready to harvest.
When the vegetative space is empty, you start the next set of young plants. As long as you keep up with starting new marijuana plants, you’ll be harvesting a full set of plants about once every 2 months. This technique is the traditional “cannabis perpetual harvest”.
Small vegetative tent for young cannabis plants on the left. Larger flowering tent on the right.
Cannabis Strain Choice
For a perpetual harvest, with this method, you need to use photoperiod (standard) cannabis strains because these allow you to control exactly when the cannabis plant starts making buds. These strains grow only leaves and stems until you give them a 12/12 light schedule, at which case it “tells” the plant to start flowering. It’s best to use strains with an 8-9 week flowering stage. If you grow strains that take longer in the flowering stage before they’re ready to harvest your vegetative tent will be popping by the time your flowering tent is ready for the next batch.
- Use photoperiod strains
- 8-9 week flowering stage
- Don’t get overly stretchy or tall
Examples of recommended strains:
- Low Odor – Northern Lights is a hardy, potent strain that tends to have less of a smell than other strains, which can be helpful for stealth reasons. Additionally, the smell tends to be more ‘spicy’ and less ‘skunky’, so it does not smell as much like cannabis. This strain is a classic that has won many awards for its effects. Northern Light plants tend to stay relatively short, bounce back easily from problems, and are quick to harvest.
- Great for Beginners – White Rhino plants respond well to LEDs by producing extra potent, extra sticky buds. Picture below. This strain is also very hardy and resistant to many common plant problems (over-watering, underwatering, stress, etc.). This strain resists mold and diseases, which can be helpful if you’re really packing the plants in your flowering grow space.
- Enormous Yields – White Widow is a legendary strain that makes huge, dense buds with a strong Indica effect and yields that can’t be beaten. This particular version is more potent than your typical White Widow, so be careful not to go overboard the first time you try it!
- Social Effects – Candyland Peyote – Good yields and the buds produce a “friendly” and energizing effect that can be good for social settings or creative endeavors. Delicious smelling and potent. An excellent strain for gathering with friends. Also a great strain to relax at home.
- High Sparkle – Gorilla Zkittlez by Barney’s Farm is remarkable for several reasons. It gives the best of Gorilla Glue #4 and Zkittlez legendary strains. These plants produce buds with particularly powerful effects that are often described as “couchlock,” “stoney” and ultra-relaxing.
- Legendary Potency – Planet of the Grapes by Ethos is extremely high potency and deserves a warning label. Picture below. Definitely not for the faint of heart with cannabinoid levels pushing past 30%. Also a very smelly and sticky plant with dense fruity buds. A strain that’s easy to grow and produces a lot of top-shelf, potent buds. Another option for legendary potency is Kushberry Moonrocks, which was developed by a geneticist and produces beautiful purple buds that measure up to 33% THC.
This White Rhino cannabis plant went through a bunch of problems (heat wave, root rot, and nutrient issues) and still produced a ton of amazing weed. Excellent strain for beginners!
The Planet of the Grapes plant I grew produced gorgeous, potent buds. I highly recommend this strain for any grower!
Vegetative Space – Small
- Holds young plants until they reach half the final desired height
- Set grow lights on a 18/6 timer. Giving plants 18 hours of light a day will keep them in the vegetative stage and get them growing fast. The 6 hours dark period every day helps make plants more resistant to problems though some growers give up to 24 hours/light per day.
Example vegetative space
- 2’x2’x4′ grow tent (100W) – 1-4 plants
- 2’x4’x5′ grow tent (200W) – Up to 8 plants
Start young cannabis plants in the smaller vegetative grow space.
Grow cannabis plants until they’re about half the final desired height.
Flowering Space – Bigger
- Once vegetative plants are the right size (half the final desired height), move them to the flowering grow space
- The flowering grow space is typically much bigger, as the plants will double in size during the flowering stage
- Set with a 12/12 light schedule (12 hours light, 12 hours dark) and make sure the space is light-proof. The 12-hour daily dark periods are necessary to get plants to produce buds
Example flowering space:
- 2’x4’x6′ grow tent (300W) – Up to 4 plants
- 4’x4’x6′ grow tent HPS version (600W) – Up to 8 plants
- 4’x4’x6′ grow tent LED version (600W) – Up to 8 plants
Once plants are half the final desired height, move the cannabis plants into the flowering grow space. They will about double in height from this point.
Now is the time to start the next set of plants in your vegetative grow space. The seeds will have time to germinate and grow to half the final desired size while this set of plants is flowering.
The flowering space is typically much bigger and kept on a 12/12 light schedule to initiate bud formation. Most photoperiod cannabis strains need about 2 months after they start receiving 12/12 until they’re ready to harvest.
Harvest!
Hints for success in your perpetual harvest:
- If vegetative plants get too big but other tent isn’t ready yet, just bend over the tallest stems and tie them down, or even just trim the whole plant (cut the branches) to be shorter. Vegetative plants can handle almost anything and will keep growing like a bush even if you cut it short like a hedge. As long as you leave lots of growing tops, you can keep hacking away the tallest part of the plants to buy more time. This is a great time to do some plant training to make plants flat and wide like a table with many bud sites. This maximizes yields later because you’ll have tons of bud sites all growing the same distance from the grow light.
If cannabis plants are getting too tall in the vegetative space but you still need more time before the other tent is ready…
Bend over the tallest branches or even just trim the whole plant to be shorter. This will buy you time until the flowering space opens up.
I used plant twist tie to hook on to each branch and tie it down. I attached the other end to the fabric pot.
How to attach to the pot? You can use safety pins or binder clips but I think this is easier. Poke holes in the fabric using sharp pointy Fiskars pruning scissors and thread the twist tie through.
Method 2: Autoflowering Strains (plant seeds on a schedule)
While standard (photoperiod) cannabis plants need a 12/12 light schedule in order to start making buds, auto-flowering strain automatically starts making buds after a few weeks to a month and doesn’t need any special time schedules. That means you can have young and old plants all together in the same grow space and they’ll still develop normally.
In this tent, the biggest plant is close to harvest and was germinated 80 days ago. The smallest plants germinated just 35 days ago, and the others got germinated at different stages in between. This grower has a pretty full house so he’s waiting until he harvests the bigger plant before germinating the next seed. As long as he keeps germinating new seeds when a plant gets harvested, he’ll have a steady stream of plants.
Different auto-flowering cannabis plants at different stages of life in one grow space.
Pros
- Perpetual harvest
- Easy – just plant a seed when you have room in the grow space
Cons
- Can be difficult to deal with different heights since plants want to be about the same distance from the lights
- If a plant doesn’t auto on schedule, it can grow out of control and crowd out your other plants
Recommended example setups
- 2’x4’x6′ grow tent (300W) – Up to 4 plants
- 4’x4’x6′ grow tent HPS version (600W) – Up to 8 plants
- 4’x4’x6′ grow tent LED version (600W) – Up to 8 plants
Hints
Height Control
- If you can set the shorter cannabis plants on something, like a box, it can help minimize height differences.
- You can help control height with plant training/bending, though you don’t want to go overboard with auto-flowering strains or they can get stunted.
- Check out the auto-flowering plant height control guide.
Strain choice
- Use trustworthy breeders that are known for consistency. If possible, use a seed breeder that specializes in auto-flowering strains.
- Choose auto-flowering strains with relatively short lifespans (under 80 days if possible) because longer-flowering plants tend to get huge and overtake the grow space.
Suggested auto-flowering strains
High THC – high potency with strong physical and mental effects
- Girl Scout Cookies Auto (up to 25% THC)
- Pluto Cut Auto (about 25% THC, but up to 30% total cannabinoids)
- Do Si Dos Auto (over 25% THC)
High CBD, Low THC under 1% – anti-anxiety strain with subtle mental and physical effects (note: it won’t get you “high”)
- Ringo’s Gift Auto (up to 25% CBD)
Above-Average Yields
- Amnesia Haze Auto
- Cinderella Jack Auto
- Orange Bud Auto
- THC Bomb Auto
- Ultimate Auto – best yields I’ve ever gotten from an auto-flowering strain, classic 90s effects
Relaxing and Uplifting Bud Effects
- GG4 Auto (autoflowering version of Gorilla Glue #4)
- White Widow Auto
- Zkittlez Auto
Purple Auto-Flowering Strains
Modern auto-flowering cannabis strains make buds that grow big, fat, and sparkly.
Conclusion
You now have learned two different ways to create a perpetual harvest for unlimited cannabis buds. The cool thing about either method is they’re flexible! Even if you don’t get the timing just right, you are guaranteed to get a ton of awesome weed!
Ready for more cannabis growing articles?
- How to Grow Cannabis in 10 Easy Steps – Growing cannabis can seem like it’s complicated, but often it only seems that way because you haven’t been given the right information. A lot of people unintentionally make growing harder than it needs to be, but that ends now! This cannabis growing guide will help you discover the best way to grow cannabis, for your unique situation.
- Complete Cannabis Grower’s Shopping List – When Sirius and I run our growers class, this is the part that trips people up more than anything. Growers spend more mental effort on their setup than picking strains or the grow itself. Don’t do that! Get stuff that’s known to work well so you can move on and not think about that aspect anymore and concentrate on your babies.
- When do I harvest? – It’s harvest season for outdoor growers, so don’t miss this helpful article to help you know exactly when to harvest. Check out the picture gallery of “ready” and “not yet ready” buds!
