Your flowers might have faced a particularly cold winter, or had too much — or too little — exposure to heat and sunlight. Buds can also fail to open because of improper care. According to The Spruce, adding too much fertilizer or pruning the plant at the wrong time can also adversely affect bud behavior.
The most common factors associated with blooming, or lack thereof, include light, plant age, nutrition, extreme temperatures and improper pruning. Many woody plants must reach a certain age before they are mature enough to produce flowers.
Often, buds fail when high light plants are in low light settings, if they are initiated at all. At the same time, plants accustomed to low light situations may overheat in direct sun, causing buds to fail. Move these plants to more appropriate lighting conditions or provide supplementary light indoors.
If you want your plants to grow flower buds, make sure your fertilizer contains phosphorus. You should use a 5-30-5 fertilizer to speed up flower production for flowering plants. Using a liquid fertilizer of this strength every other time you water your plants, you can mix it to half strength.
However, complete fertilizers sold for flowering plants (including roses and bulbs) such as 15-30-50 or 10-30-20 contain higher amounts of phosphorus (the second number) than nitrogen or potassium and are often labeled as “blossom or bloom booster”.
Lack of light is perhaps the most common reason that cannabis produces fluffy, light buds. You may have noticed the lower, puny 'popcorn' bud sites that form below the main canopy.
Overwatering is one of the most common mistakes made by new cannabis growers. It's like suffocating your plants, and one of the main reasons behind slow growth, nutrient deficiencies, root rot, fungus, and many other problems. Don't water too often and do not water on a fixed schedule.
Many of the buds turn brown and never fully open. What can I do to fix this problem? Botrytis blight is the culprit. It is most common on white and pink roses during wet weather.
Cannabis plants are happiest when they get between 10–12 hours of direct sunlight per day.
Any kind of stress, be it from poor watering, a lack or excess of nutrients, the environment, pests, plagues, or improper care, can affect a plant's ability to grow big, dense flowers.
Your plants have the symptoms of a fungal disease called botrytis (Botrytis cinerea) This disease prevents the blooms from opening; buds turn brown and decay. Sometimes partially opened flowers are attacked and individual petals turn brown and shrivel.
Even these trichome-heavy, tiny leaves will give your buds a harsher experience, so it's best to remove them — but definitely don't waste them! Why? Because if you collect all the plant matter you cut off your buds, you can later use them to create other products such as hash, teas, butter, tinctures and edibles.
In the beginning, bud rot attacks a plant's stem, which will appear mushy and gray. As the infection progresses, signs of bud rot are characterized by wilted, yellow and burnt leaves. It's tricky to spot bud rot ahead of time because the fungus first takes hold inside the plant and works its way to the outside.
The first noticeable symptom is a wispy white mold. Then, the rot turns gray, then black. At this point, the buds will take on a slimy, mushy consistency. If bud rot is discovered early, you can take action to prevent further damage.
Remember that fan leaves removed during flowering won't grow back, and removing too many can throw off the plant's energy balance, stunting bud development in turn.
Light intensity
To some degree, more light translates to fatter buds and higher yields (you'll need to pay attention to the distance between your grow light and plants or your plant may suffer from light burn). Increasing light intensity is the most effective way to fatten up buds.
Nutrients for blooming contain more phosphorus and potassium than nitrogen. Phosphorus plays a major role in the plants breathing and is essential for flower formation.
Fermented fruit juice (FFJ) is an effective homemade bloom booster containing high amounts of phosphorous, potassium, hormones, enzymes, and beneficial micro-organisms. FFJ is made by mixing fruit and sugar, which produces a liquid that is extracted after 5 to 10 days, and applied as a foliar spray.
Epsom salt can improve the blooms of flowering and green shrubs, especially evergreens, azaleas and rhododendrons. Work in one tablespoon of Ultra Epsom Salt per nine square feet of bush into the soil, over the root zone, which allows the shrubs to absorb the nutritional benefits.