The business end of a cannabis grow is always the most exciting, and there's nothing more satisfying for cannabis growers than seeing their buds fatten up. It's at this point in the flowering cycle that the grow room starts to come alive with the unmistakable aroma of cannabis resin, and while not all strains will ripen at the same rate, there is a general window in which most cultivars will start to bulk out and become stacked.
When Do Buds Ripen?
Every grower looks forward to the moment when they can switch their photoperiod to a 12/12 cycle. Doing so signals the end of the vegetative stage and provides the trigger for cannabis plants to bloom. Of course, though, this doesn't happen overnight, and the first few weeks of the cannabis flowering stage are generally taken up with pre-flowering activities like stretching.
It's not until about two to four weeks into the flowering stage that this growth spurt comes to an end and the sexy business of growing inflorescences begins. Naturally, the exact timing depends on the strain you're working with, but it's usually around this point that growers start to notice flowers developing from the white hairs covering the nodes.
So, when exactly do buds fatten up? Well, as mentioned, that depends on genetics. Buds can begin to appear from about two weeks into bloom, and faster indica varieties may start to bulk up as early as the fourth week of flowering. Lankier sativa cultivars, meanwhile, tend to take a little longer to get going. As a general rule, though, weeks five and six of the flowering stage are when cannabis plants begin to get that stacked look as bud sites fill up with burgeoning inflorescences.
Which Strains Are The First To Fatten?
Autoflowering cannabis strains typically have a faster life cycle than photoperiod cultivars and can be fully budded up and loaded with trichomes in as little as nine or ten weeks after germination. Northern Lights Auto, for instance, requires about four weeks for veg and five or six weeks for flowering. With a cultivar like this, buds start to chunk up between the second and fourth week of the flowering stage. In other words, from about week five to week eight of the overall grow cycle.
Of course, not all autos are quite that speedy, and some can take a few extra weeks to mature. The same goes for photoperiod cannabis, so don't panic if your buds still haven't entered their glory days by week five or six of bloom. Different strains have different rhythms, and some are just a little later to the party than others.
Growers working with fast-flowering cultivars like Royal Dwarf, for instance, might notice their buds putting on weight earlier than some other cannabis plants. Conversely, the buds on Mama Thai and other similar strains can take a little longer to hench up.
On average, though, most cultivars will begin developing chunky buds after about five weeks of flowering. It's typically also around this time that trichomes start to become visible on the flowers and sugar leaves. Inside these crystalline chemical factories is where you'll find all the THC, CBD and other cannabinoids, so don't be surprised if your plants' aroma becomes more full-bodied at this point in the flowering stage.
For those trying to keep a low profile, now might be a good time to invest in a carbon filter to prevent the smell from giving you away!
What To Do If Your Buds Don’t Fatten On Time
When cannabis plants turn their attention from vegetative growth to bud development, they require a certain amount of help from growers. Cannabis flowering is energy-intensive stuff, so plants need the right nutrients in the right amounts to ensure they have what it takes to make the magic happen.
If your buds aren’t looking too clever, there’s a high chance that you’ve given them too much or too little of a particular nute. As with all stages of the grow cycle, it's important to find that sweet spot where plants suffer from neither nutrient deficiencies nor nutrient burn. However, this becomes even more imperative during flowering as plants are more sensitive to diet changes at his point in their lives.
As growers, our responsibility is to make sure plants have extra potassium and phosphorus when buds are fattening. These two essential nutrients – which make up two-thirds of the NPK combination – help to promote flowering and are therefore needed in higher quantities when it comes to making colas.
In contrast, nitrogen helps to stimulate vegetative growth and is therefore in higher demand during the earlier part of the cannabis life cycle. And while a healthy amount of N is still needed during flowering, this particular nutrient won't help those buds ripen.
For this reason, it's worth using a bloom booster such as PK 13/14 to provide your plants with enough phosphorus and potassium to grow those monster buds.
It's also worth remembering that cannabis plants stop growing leaves once they enter the flowering cycle. This means it's extra important to take care of the ones you've got, as fan leaves are the photosynthesis factories that power the growth of flowers.
Often, growers will prune away some leaves if they happen to be blocking bud sites, and it is of course important to make sure those colas aren't crowded out or denied access to the light. But aggressive defoliation is certainly not advised during cannabis flowering, as this can prevent buds from reaching their full potential.
On a similar note, now is also the time to stop with any low-stress training techniques you may have been using earlier on. When buds start to fatten, you want to keep them upright rather than tying them down, and you may even need to provide extra support in the form of stakes or nets to help plants deal with the rapidly expanding weight of the developing colas.
Despite being on the final stretch, then, there’s clearly still lots to think about. With several weeks remaining until harvest, the fattening of the buds does not give growers the right to get complacent or take their eye off the ball, as things can still go wrong if plants aren't properly cared for. However, it is undoubtedly a moment to enjoy and a sign that all your hard work up to this point is paying off.