There are so many questions that come with growing cannabis for the first time. Notably, how long do growers have to wait before the flowering period? How many weeks does it take for a cannabis plant to flower? Keep reading to find out.

So, once you have flipped your photoperiod cannabis plants from their vegetative growth stage to their flowering stage by transitioning to a 12-12 light cycle, or your autoflowering female plants that don’t require a 12-12 lighting schedule as they are able to automatically transition themselves to their flowering period, the next logical question you as a new cannabis grower are probably wanting to ask is: “How many more weeks before harvest time?”

For a good majority of cannabis strains, their flowering phase lasts 7-9 weeks, although sativas and sativa-dominant hybrids can take some extra time of up to 10-12 weeks to flower if you’re not using any particular growing methods to help shorten this time.Every single weed strain has its own particularities with how long they’ll take to flower and if and when they’re most susceptible to issues such as pests, molds, mildew, and diseases. Since there is no way to give an exact time frame for exactly when their flower sites will produce buds that are ready for the plucking, we’ll instead give you the general averages for things. For more exact info about the exact strain you’re growing, you need simply to refer to the information provided by the seed bank whom you purchased your feminized seeds from.

The Stages of Flower Development Week By Week

The First 1-3 Weeks: Post-Vegetative Stage

Week 1: In the first week of the flowering stage, don’t worry if you don’t see any bud sites, as the first two weeks are the time in which your cannabis plants are adapting to the 10-12 hours of uninterrupted darkness they are getting. During Week 1, you can anticipate your plants hitting a post-vegetative growth spurt where, depending on their genetic composition, can near-double in height during what is known as their stretch phase. As such, you will want to make sure you have given them enough space in which to grow. Furthermore, because their faster growth and height during a stretch can get out of control, this may be when you would want to employ using a low-stress training (LST) technique where you bend the stems down and away from the center stalk so that you can get a more consistent average canopy height, which not only serves to get the best use out of your grow lights but can also serve to ensure better-quality yields when harvest time does arrive. Furthermore, using LST can be especially helpful to those with height limits in their indoor growing space

Week 2: While you can expect much of what takes place during your plant’s first week in its flowering time, Week 2 maybe when you first start to see wispy white pistils beginning to emerge from your female plants. These white feathery pistils are the pre-flowers that will soon begin to give way to buds. This will also be when you will know whether or not you have a male plant, as male plants produce small pollen sacs. If you discover this, unless you are a breeder or commercial grower wanting to obtain seeds, it is imperative that you move any male plants far away from your female plants so that don’t pollinate them, as the collection of pollen will cause them to grow seeds. The second week is also when you may need to increase feeding your plants by adding additional nutrients so that they don’t suffer from any nutrient deficiencies, which would prohibit them from achieving their maximum potential in terms of yield quantity and quality. However, it’s important that you check the nutrient schedule provided by the manufacturer as to when and if you will need to do so, as overfeeding can result in nutrient burn.

Week 3: The third week is when your weed plant should be nearing the end of its stretch period as it slows down until it completely stops. In the areas where you discovered those white pistils growing, you’re likely to start seeing some buds starting to form in their growth nodes. Making sure that your plants are getting enough nutrients is vital at this time, as this is when your female plant is using the most energy to grow flowers. If your plants are suffering from nutrient deficiencies they’ll likely start producing discolored, yellowing leaves or will begin to lose entire leaves. If your plants are struggling with nutrient burn from being overfed, your plant’s leaf tips will start to show signs of discoloration, which you can easily resolve by cutting back on how much you’re feeding them. Finally, Weeks 2 and 3 are when you will want to start to really focus on pest management, like watching out so that, for example, you don’t end up with an aphid issue; disease prevention; and powdery mildew and mold, where for example if you start to notice gray mold it’s a strong indicator that you have an issue with botrytis, aka “bud rot.” The reason this time period is so significant is you want to get any and all issues under control before buds start to develop in the third and fourth weeks.

Small cannabis plant in potted soil
Check out our blog for more information on the flowering time of cannabis plants
Source: Indorgro Unsplash

Weeks 4 and 5: Mid-Flower Stage

Week 4: This is the week in which your marijuana plants have stopped growing and your plant height has reached its max. As such, if you employed LST, you can, if need be, provide them with the structural supports they need so as to stay upright. While the mid-flowering phase can start as early as Week 3, generally speaking, Week 4 is when the buds start to fill out and increase in size, and trichome production really kicks into full gear. Since you’re doing a legal grow, it probably shouldn’t be much of an issue that the increase in trichomes means that its pungent fragrance is going to be announcing itself, which is why many indoor growers use charcoal activate filters, etc. because even in places where it’s legal to grow weed, not everyone wants their neighbors or guests in their home to be made aware of their grow room setup.

Week 5: The fifth week is usually when your autoflowering or photoperiod plants should really be in the prime of their mid-flower phase as this is the time in which you should really notice that the nuggets of your indoor and outdoor plants are getting thicker, that you’re getting more and more dense flower formations, and that more and more new buds are popping up. Depending on your strain’s characteristics appearance-wise, Week 5 is when the white pistils may start to turn brown, amber, orange, red, etc. This is also when its trichome production really kicks into gear, and the trichome heads start to turn milky white in color. Know that when the pistils start to darken, and the trichome heads start to turn opaque, these are solid indicators that not on are your plants entering their full flowering stage, but that you are nearing harvest time.

Weeks 6-8: Late Flowering Stage / Ripening Phase

The final weeks of your plant’s flowering stage are the time in which the bud or flower weight will really increase and when their fields of trichomes will really be reaching their full potential.

Depending on your strain will depend on when you’ll be able to harvest your plants in its final couple of weeks. As a general rule of thumb, most weed strains aren’t ready for the picking until the eighth week, but there are definitely various autoflowering and photoperiod plants that can be harvest-ready in 6-7 weeks, just as there are those that won’t be ready until Week 10 or even Week 12.

Usually, your buds will have achieved their peak size between Weeks 6 and 7, so the final two weeks or so before harvesting isn’t about them growing in size but rather maturing in density and blossoming into their proper coloration and finishes.

Aside from the nuggets achieving their full-color spectrum, size, and density, the two biggest indicators for knowing when they’re ready to harvest are as described below:

  1. 1. While you’re unlikely to see many new additional pistils growing during the last couple of weeks, the pistils that have already grown won’t only start to take on their full color but will start to tuck or curl inwards.
  2. 2. Using a small microscope or a handheld magnification device like a jeweler’s loupe, you’ll want to examine the trichomes and if any are still transparent in coloration, it’s too soon to start picking them. However, when the majority of the trichomes are opaque and amber in color, this is a sign that the THC content and synthesis of cannabinoids are at their peak, and now’s the time to harvest.
Ground up cannabis flower
The key to a high-yielding marijuana plant is knowing the right time to harvest
Source: Laura Jaramillo Bernal Unsplash

Things to Do Before Harvesting

Before you harvest your buds, which can be a truly exciting moment for first-time growers, you will first need to flush your outdoor or indoor plants about two weeks before reaping your rewards. To do so, you will need to stop feeding nutrients to your plants, and only water with pH-balanced water. The reason for doing this is that this will flush out any minerals etc. in your healthy soil that can result in harsher, more unpleasant-tasting buds. However, some prefer to skip this step, especially if they’ve been using chemical-free organic soil, and are happy with the outcome.

Some Tips for a Better Harvest and Top Flower Quality

So, now that you know what to anticipate week by week during your plant’s flowering phase and indicators that its buds are ready to harvest, let’s end with providing you with a few extra tips and tricks for getting the best harvest possible.

Resolve Issues Before They Flower

If you’re an indoor grower, then you can choose when to put your photoperiod plants onto their new light and dark cycle where they get an average of 12 hours of darkness, and 12 hours of light per day. Having control over the environmental conditions of your grow space and when your plants enter their flowering stage is advantageous as you can wait to flip your plants until you know that they are healthy.

If you are growing outdoors, you’ll have to keep a close eye on the calendar and fix any issues before the autumn in the last summer days or weeks. That said, the one way to be in control of when your crops start their flowering stage is if you have the time and ability, you can put your outdoor photoperiod cannabis plants on a 12-12 light schedule by putting tarps over cannabis crops that they have growing. It is imperative that the tarp or covering you use can provide total and complete darkness with zero light leaks, and you’ll have to every day and night move and replace the covering so that your plants are getting 10-12 hours of direct light and dark periods that they need. Quite bluntly put, most find this continual process to be too much of a hassle as their lives then become dictated by the hours per day and hours per night they need of light and darkness to flower.

Lighting, Lighting, Lighting

For indoor cultivators, using the right kind of artificial lights is integral to the successful growth of your weed plants. When your plants are in their bloom phase they do best under grow lights that are 580-700 nm with red and orange wavelengths.

Lower Humidity Levels

While many strains respond well to 65-75% relative humidity during their seedling stage and vegetative growth time, keeping the relative humidity of your grow space or tent at 45% helps protect your plants from bud rot as it ensures dry conditions and can help prevent healthy roots from developing root rot.

Maintain the Temperature

Another advantage to cultivating weed indoors when doing some cannabis home growing is that you can control the weather conditions at all times, as well as all other envy. When your plants are in their flowering period, they usually prefer daytime temps that range from about 70-75 degrees Fahrenheit and evening temps that are between 60-64 degrees Fahrenheit. Note that abrupt transitions in dropping to colder nighttime temperatures can shock your plants, and sudden increases can cause an increase in moisture levels on the surfaces of your nuggets, which can result in bud rot. As such, keeping temperature levels steady can make a huge difference in their flowering process.