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Big Bud Auto Cannabis Strain Week-by-Week Guide

Watch how Big Bud Auto grows from seed to harvest: from the vegetative phase through the different stages of flowering
02 February 2022
12 min read
Big Bud Auto Cannabis Strain Week-by-Week Guide

  • 1. Grow specifications
  • 2. Grow set up
  • 3. Germination and seedling stage | week 1
  • 4. Early veg | weeks 2-3
  • 5. Mid veg | weeks 4-5
  • 6. Transition (pre-flower) | weeks 6-7
  • 7. Early flower | weeks 8-9
  • 8. Mid flower (bulk phase) | weeks 10-11
  • 9. Ripening and harvest | week 12
  • 10. Yield and smoke report
  • 11. In conclusion

Big Bud Auto is one of the stars in our “Originals” collection. Like many other tried-and-true classics, she’s stable, totally reliable, and hardy which makes her a perfect choice for beginners. Nevertheless, if you’re still nervous about your first-time grow, you get a chance to follow this autoflower’s week-by-week progress and see for yourself how easy she is.

1. Grow Specifications

Like the name suggests, Big Bud Auto produces huge, bloated colas and yields as much as 500 g/m2 (1.6 oz/ft2). She’s one of the faster varieties and takes only 8–9 weeks from seed to harvest while reaching a moderate height of 90–120 cm (35–47 inches).

Thanks to her strong Indica heritage, Big Bud Auto is also a terrific outdoor variety, tolerating cool and even rather cold climates but still capable of bringing respectable yields — 50–150 grams (2–5 ounces) per plant.

Trimming your harvest will be a breeze thanks to an excellent calyx-to-leaf ratio, and you’ll be left with lots of super-dense nuggets that have a pleasantly sweet, fruity, and floral smell. 

Big Bud Auto Cannabis Strain Week-by-Week Guide: Datasheet

Big Bud Autoflower datasheet.

The THC content can reach 23%, and it means that you’ll only need a couple of hits to get a relaxed floating sensation in the body with a mildly stimulating head high. This is exactly the kind of effect that you’ll need to wind down after a long busy day.

2. Grow Set Up

Our version of the autoflowering Big Bud has been introduced only recently, and we could find only five finished grow cycles. However, the strain is so predictable, that one can take any of those reports and get a perfect idea of what to expect.

We chose the diary by JohnnyBlaze who grows his autoflowers in a small 1m2 nook in his bedroom, using a 150W Mars Hydro TS 1000 LED light and some basic ventilation. But this setup is sophisticated enough to maintain a steady day temperature of 26°C (79°F) and keep the relative humidity at a comfortable 60%.


Grow Space:1 m2 (10.76 ft2)Pot Size:11 l (2.91 gal)
Seed to Harvest:12 weeksMedium:100% coco coir
Flowering:7 weeksNutrients:Synthetic/Organic
Light Cycle:19/5 → 20/4pH Levels:6.1
Light Type:LEDDay Temperature:26°C (79°F)
Watts Used:150Humidity:60%

Big Bud Auto setup and grow specifications.

3. Germination And Seedling Stage | Week 1

The grower used the Easy Start kit for germination. It’s basically a tray of tiny pots where each is pre-filled with soil. Also, there is a small packet of a bacterial root stimulant. But all this isn’t really necessary.

If you’re a beginner gardener, you can simply pre-soak the seed in a glass of water for 12 hours or so, then put it between wet paper towels, and keep it there until the taproot reaches 0.5–1cm (¼–½ in). Then the seed goes straight into the medium, and we recommend planting it into the final pot—the one that you’re going to use till harvest. This way you’ll spare the plant the risk of shock when re-potting.

Big Bud Auto Cannabis Strain Week-by-Week Guide: A tiny germination pot filled with moist medium and a marijuana seedling

The Easy Start pot right before the germination and the seedling on day 5.

In this case, the pot that the grower used from seed to harvest contained 11 liters (2.91 gallons) of 100% coco coir. This is a medium that has no nutrients for a plant to feed on. Moreover, coco requires extra amounts of calcium and magnesium. So, when you water your seedling, you’ll need to mix in some nutrients from day one. At first, the dose should be very small. Otherwise, a too strong solution would harm the little one.


Plant Height:2.5“ (6 cm)Humidity:60%
Distance to Light:23.5“ (60 cm)Water per Day:0.05 gal (0.2 l)
Day Temp: 79°F (26°C)pH:6.1
Night Temp: 66°F (19°C)TDS:300 ppm

Week 1 grow conditions.

The first couple of weeks are also the right time to inoculate the medium with living organisms—bacteria and mycorrhizal fungi. What these little creatures do is help the roots of the plant split complex organic molecules into simpler nutrients. In this particular instance, the grower used the following two inoculants by Advanced Nutrients:

  • Voodoo Juice (microbes),
  • Piranha (beneficial fungi).

He would go on adding them throughout the vegetative phase to increase the root mass and improve the water and nutrient uptake.

4. Early Veg | Weeks 2-3

The second and third weeks from seed is the time when cannabis continues developing the root system, while the progress “upstairs” is moderate at first but then begins to pick up the pace. The young plant may get a bit thirstier than before, but the appetite remains the same—around 300 ppm should be enough before the rapid vegetative growth kicks in.


Plant Height:4-4.7“ (10-12 cm)Humidity:60%
Distance to Light:23.5“ (60 cm)Water per Day:0.05-0.08 gal (0.2-0.3 l)
Day Temp: 79°F (26°C)pH:6.1
Night Temp: 66°F (19°C)TDS:300 ppm

Weeks 2-3 grow conditions.

This Big Bud Auto was growing vigorously and without any signs of stress, so the grower decided to top her on day 20. This potentially stressful procedure didn’t slow down the progress for more than a day or two, and now that the top shoot was gone, the side branches at lower nodes began to develop faster.

Big Bud Auto Cannabis Strain Week-by-Week Guide: A 3-week old ganja plant topped and growing new side branches at the nodes

The top was pinched off on day 20, and Big Bud Auto took it like a champ.

Topping autoflowers is becoming a standard technique for experienced growers because modern autos are much more resilient than the first generations were. However, if you’re only dipping your toes into cannabis cultivation, you better stick to the less invasive LST method. It’s enough to keep the canopy low and flat and will increase the yield without the risk of stress.

5. Mid Veg | Weeks 4-5

The latter part of the vegetative phase marks the moment when cannabis suddenly “explodes”, seemingly overnight. The appetite for plant food increases, and the plant can also handle more light. So you may lower your LED or turn up the dimmer to full power.


Plant Height:19-24“ (48-61 cm)Humidity:60%
Distance to Light:50“ (127 cm)Water per Day:0.08-0.11 gal (0.3-0.4 l)
Day Temp: 79°F (26°C)pH:6.1
Night Temp: 66°F (19°C)TDS:400 ppm

Weeks 4-5 grow conditions.

Whatever stress (from topping) Big Bud Auto experienced in the previous week, she was over it now. The girl handled LST beautifully and became a wide and bushy plant.

this plant has fully recovered from the topping i did on her and now growing in size very fast.. She has a very nice green colour meaning she's very healthy and now forming a very nice shape...


Big Bud Auto Cannabis Strain Week-by-Week Guide: The tie-down method started on a 4-week-old plant and the same plant, bushy and wide, after another week

The beginning of LST in week 4 and the explosive growth in week 5.

And here is the complete schedule for the vegetative phase. Please note how much the doses of nutrients increased for the last two weeks before the pre-flowering stage.


Nutrients, ml/lWeek 1Week 2Week 3Week 4Week 5
Voodoo Juice22   
pH Perfect Sensi Coco Grow A0.20.50.811.2
pH Perfect Sensi Coco Grow B0.20.50.811.2

Big Bud Auto feeding schedule for the vegetative phase.

We already mentioned the first two of the amendments in the list—Voodoo Juice and Piranha. Their mission is to colonize the root zone with millions of beneficial microbes.

Then comes the 2-component liquid fertilizer pH Perfect Sensi Coco Grow A and B. It contains all the nutrients that cannabis needs, and since it’s a formula for the growth stages, it contains more nitrogen (N) than phosphorus (P) and potassium (K).

This very short video explains the basics of feeding your autoflower.

The B-52 supplement is a bunch of vitamins and plant growth regulators extracted from seaweed. It helps marijuana grow stress-free. Finally, Grotek Cal-Max is a source of calcium, magnesium, and iron. As we have explained, the first two get especially easily depleted in coco. Those gardeners who switch from soil sometimes learn the hard way how much more Ca and Mg they need to use in coco.

Magnesium deficiency makes the lower leaves get yellow between the veins, and in calcium-deficient plants, the leaves in the middle and upper part become spotted, dry, and twisted. So keep your eyes open.

6. Transition (Pre-Flower) | Weeks 6-7

The pre-flowering stage is the time when cannabis begins to have first pistils at the nodes and on every top, and in autoflowers, this process happens automatically. Meaning that for autoflower flowering stages, you can keep the same light schedule as you had during the vegetative stage. It was 20/4 in this cycle.


Plant Height:24-35“ (61-89 cm)Humidity:60%
Distance to Light:40“ (102 cm)Water per Day:0.2 gal (0.75 l)
Day Temp: 79°F (26°C)pH:6.1
Night Temp: 66°F (19°C)TDS:400-1000 ppm

Weeks 6-7 grow conditions.

The start of flowering doesn’t mean that the vegetative growth stops or even slows down. You can see in the table above just how much height Big Bud Auto gained at the beginning of her second month.

Only when the buds start to fill out, does this flowering stretch, as we call it, stop. You should always keep this in mind, or otherwise, you can get out of vertical space really fast. For photoperiod varieties, you can control the final height by switching to 12/12 in time. With autoflowers, control the size of the plant by choosing the right-sized container. The smaller the pot, the smaller the root ball which directly determines the size of the visible (above-surface) part of the plant.

Big Bud Auto Cannabis Strain Week-by-Week Guide: Two shots of the same plant with a lot of branches and tops that has just started flowering

A lighter shade of green on the tops is a sign that flowering has started.

In this case, the girl grew quite big, but the topping and LST increased her girth and decreased height.

7. Early Flower | Weeks 8-9

Over the previous two weeks, the grower had been gradually raising the dose of nutrients until the readings on his TDS meter reached 1000 ppm. And this level he would keep for the next two weeks as well.


Plant Height:24“ (60 cm)Humidity:60%
Distance to Light:40“ (102 cm)Water per Day:0.26 gal (1 l)
Day Temp: 79°F (26°C)pH:6.1
Night Temp: 66°F (19°C)TDS:1000 ppm

Weeks 8-9 grow conditions.

The standard advice for cannabis flowering stages is to use nutrients where N plays only a minor part and P and K come centerstage. The reason is that N is necessary for the growth of foliage while the development of flowers requires more P and K.

It’s easy to achieve this goal by simply switching from a grow fertilizer to a bloom formula, as was in this case where the grower stopped giving his autoflower pH Perfect Sensi Coco Grow A and B and replaced it with pH Perfect Sensi Coco Bloom A and B. But being a very experienced gardener, his diet was much more sophisticated than that, and he would tweak it for different stages of flowering.

Let’s have a look at the complete list:


Nutrients, ml/lWeek 6Week 7Weeks 8-9Weeks 10-11
Voodoo Juice22  
Bud Ignitor22  
pH Perfect Sensi Coco Bloom A1.
pH Perfect Sensi Coco Bloom B1.
Bud Candy2222
Rhino Skin1.
Bud Factor X0.50.511
Big Bud Coco 12 
B-52  1.51.5
Nirvana  1.51.5
Overdrive   2

Auto Big Bud nutrient schedule for the flowering stage.

When you make a decision about your own feeding schedule, it doesn’t have to be so complicated. It can be very hard juggling so many components at once, especially for novices. However, we’ll describe briefly what different items in the table above are for and when to use them.

  • Bud Ignitor. A PK formula to jumpstart the process of budding; use it for only the first two weeks of the flowering stage.
  • Bud Candy. Cranberry and grape extracts to load your buds with sweet aromas and flavors.
  • Rhino Skin. A source of silicone that will toughen cell walls and prevent branches from snapping under the weight of buds.
  • Sensizym. Contains enzymes and small amounts of P and K and turns the root zone into an organics bonanza; apply it throughout cannabis flowering stages.
  • Bud Factor X. A bio-active blend to boost photosynthesis and increase the production of resin and terpenes in cannabis.
  • Big Bud Coco. One of many Big Bud supplements, this one is for those growing in coco coir. It contains a lot of P and K and is used throughout the early and middle flower but gets replaced by Overdrive for the last couple of weeks before the final flush.
  • Nirvana. A high-potassium organic supplement for middle to late flower; makes your buds extra large.

Big Bud Auto Cannabis Strain Week-by-Week Guide: A short but bushy flowering plant indoors and a close-up of a bud 4 weeks into flowering

Now, 4 weeks into flowering, Big Bud looks gorgeous.

The grower chose not to subject his Auto Big Bud to much defoliation. We recommend that you should do the same because leaving the foliage intact usually leads to bigger yields than heavy defoliation.

8. Mid Flower (Bulk Phase) | Weeks 10-11

We can call this point in the timeline a home stretch because buds now look more and more like they are ready to be harvested and smoked. By this time, an autoflower usually stops stretching and all of its energy goes into stacking up flowers. She is also at her hungriest and can handle very high PPM levels (1300 in this case).

We also recommend lowering the day temps a bit (73–77°F, or 23–25°C, would be just fine) and keeping the relative humidity down to 35–40% because, at higher readings, you risk problems with mold and bud rot.


Plant Height:24“ (60 cm)Humidity:60%
Distance to Light:40“ (102 cm)Water per Day:0.26 gal (1 l)
Day Temp: 79°F (26°C)pH:6.1
Night Temp: 66°F (19°C)TDS:1300 ppm

Weeks 10-11 grow conditions.

This is also the time in the life cycle of an autoflower when you should begin to watch for signs of approaching harvest. It’s important because it’ll allow you to choose a perfect moment to stop feeding your plant any nutrients and begin the final flush.

Start with watching the daily progress of your buds. When they stop fattening, it’s time to watch for the second sigh of maturity: the pistils, female hairs on the buds, will turn amber. Or maybe some other more exotic hue, like purple or pink. The main thing is that they change their color from greenish-white (immature) to something else (mature). It means you have mere days now before the harvest.

Big Bud Auto Cannabis Strain Week-by-Week Guide: A close-up of an indoor bud with a lot of trichomes and a 50/50 ratio of white-to-brown pistils

Fat, dense, and sticky cola, but it still has white pistils and isn’t quite ready yet.

Finally, when there are no more white hairs growing from the buds, it’s time to take a hand microscope and watch the color of trichomes. Trichomes are tiny transparent glands that look like mushrooms when magnified. They cover both the buds and the small “sugar” leaves sticking out from them.

Watch the trichs on the buds, not leaves, and when most of them turn from clear to cloudy, you have just enough time to flush your auto for up to one week and then chop it. Trichomes in cannabis contain cannabinoids and terpenes, and when they become cloudy, the levels of these compounds are at their peak.

Later, some of the trichomes will start to turn amber which means that THC begins to degrade and the effect from smoking the buds will be less mind-warping and more sedating. It’s up to you to decide at what cloudy-to-amber proportion to harvest your buds.

9. Ripening And Harvest | Week 12

Not every autoflower in your garden will take 12 weeks from start to finish. Some are 2 or even 3 weeks faster than that. But with longer flowering time come bigger plant sizes and more generous harvests. And this was the case with Big Bud Auto here.


Plant Height:24“ (60 cm)Humidity:60%
Distance to Light:40“ (102 cm)Water per Day:0.26 gal (1 l)
Day Temp: 79°F (26°C)pH:6.1
Night Temp: 66°F (19°C)TDS:150 ppm

Week 12 grow conditions.

The grower was flushing his autoflower for a little more than a week, using Advanced Nutrients Flawless Finish. He hadn’t done much defoliating, so the extra foliage had a lot of nitrogen stored in it, and the plant didn’t look hungry till the very end.

Big Bud Auto Cannabis Strain Week-by-Week Guide: An indoor marijuana plant with multiple flowering tops and a closeup of a fat and solid-looking cola ready for harvest

The buds look solid, heavy, and resinous. They are ripe for harvest.

If you DO defoliate a lot, your plant gets depleted of nitrogen much faster, leading to a beautiful fade. The leaves begin to yellow, starting from the lower ones. In this case, the only signs of fade were the purple hue at some of the leaf edges.

The smell was kinda loud too, with piercing musky and skunky notes. With strains like Auto Big Bud, you should always use a carbon filter for odor control because even one plant will definitely smell a lot throughout flowering stages.

When the grower was done flushing and thought both the medium and the plant tissues were free of built-up salts, he kept his Big Bud Autoflower for 48 hrs in total darkness and without water. 

Big Bud Auto Cannabis Strain Week-by-Week Guide: A closeup of a ripe cola, glistening with trichomes

Big Bud Auto after the dark-before-harvest treatment.

Many gardeners use this technique to trick their cannabis into producing some extra resin. The jury’s still out on the efficiency of this method, but at least it doesn’t hurt.

10. Yield and Smoke Report

The grower harvested just over 19 ounces (540g) wet from this one plant and found it very easy to trim because there were only so many sugar leaves sticking out the fat and dense Indica-type buds. After 6 days of drying, he got 3.81 ounces (108 grams) of dry tightly trimmed nuggets.

Big Bud Auto Cannabis Strain Week-by-Week Guide: A trimmed, dried, and cured marijuana bud in the palm of a grower's hand and a heap of buds on the scales

Dried and cured Big Bud Auto nuggets.

Drying is never enough to bring buds to the peak of their quality in terms of potency and flavor. You also need to cure them for at least 2-3 weeks so that all the chemical processes finish within the flowers: chlorophyll (with its vulgar hay taste) degrades and so do sugars and starches. It all contributes to a smooth, mellow taste of your smoke.

Big Bud Auto Cannabis Strain Week-by-Week Guide: Terpene profile

Terpene profile of a Big Bud sample.

This particular Big Bud Auto had an awesome earthy flavor with creamy and kushy undertones, perfect for Indica lovers. In contrast, the high was a hybrid one. It started on the Sativa side, inducing a talkative and super euphoric mood. And after about an hour, the relaxation kicked in, sending one straight to the couch for the rest of the evening. The effect was also heavy enough to make you space out if you took a hit too many.

11. In Conclusion

As you can see, Big Bud Auto is a completely low-maintenance strain. If you know what you’re doing, the whole life cycle can be totally uneventful. Just watch your girl grow and admire how healthy she looks. But while growing Big Bud may be boring, smoking it is not. It’s top-notch stuff, and you’ll appreciate its buzzy euphoria followed by happy relaxation.

External References

  1. A new ESI-LC/MS approach for comprehensive metabolic profiling of phytocannabinoids in Cannabis, Scientific Reports, Sept 2018
  2. Comparative Genetic Structure of Cannabis sativa Including Federally Produced, Wild Collected, and Cultivated Samples, Front. Plant Sci., 29 September 2021


02 February 2022