Cannabis plants like temps around 70-80°F (20-26°C) in the flowering stage for best development. Temps over 85°F (30°C) usually makes buds grow parts that are noticeably more airy than the same plant grown under proper temps. Indica-leaning strains are better at handling cold Sativa or equatorial strains are better at handling heat. Too much heat triggers heat burn, airy buds, fox-tailing and also reduces potency and smell, especially for indica-leaning strains which are less resistant to heat. High temps can also lead to seedy buds if your plant herms as a result of the stress.
This bud was exposed to high temps and never really grew more than a few calyxes and lots of sugar leaves. Fox-tailing caused by heat – the entire bud is larfy and airy. Too much heat causes thin buds and strange growth patterns. Too-cold temps (especially during first 6 weeks of flowering) are less common but can also cause airy buds that don’t ever fatten up and grow dense. Cold temps can also keep buds from developing, like this outdoor plant grown in a cold climate. Cold temps can also cause leaves and stems to turn purple. Purple leaves can be problematic since green leaves make more energy from light. That’s why it’s a good idea to avoid letting leaves turn purple too early in the flowering process. Although indica-leaning strains tend to be more cold-resistant and sativa-leaning strains tend to be more heat-resistant, almost all strains available today are some sort of hybrid.
Instead of relying just on a strain’s classification as Indica or Sativa, it’s important to learn about the particular strain and how it reacts to heat and cold. Even more importantly, watch your plant for signs of stress! 4.) Nutrients – Use the right N-P-K ratios for the flowering stage! (but don’t go overboard) Give your plants the right ratios of cannabis nutrients during the flowering stage (while avoiding nutrient burn). Not only does this help you avoid nutrient deficiencies, it also gives your plant the building blocks needed to make buds. It can be tempting to ignore this part, but pH is also incredibly important when it comes to nutrient absorption. Managing pH properly is one of the best ways to make sure that plant has easy access to nutrients at the roots. The N-P-K values are listed on the back of most nutrient bottles. What nutrients does a cannabis plant need in order to make dense buds? In the budding stage, make sure to provide a little Nitrogen, a lot of Potassium, and a good source of Phosphorus. Best for cannabis flowering stage (“Bloom Nutes”): A little Nitrogen (N) A good source of Phosphorus (P) – definitely more than Nitrogen, and possibly more than Potassium as well A lot of Potassium (K) – about double the amount of Nitrogen or more. Giving relatively low levels of Nitrogen during the flowering stage helps buds fatten up. It’s important to avoid giving too much N while plants are budding, as too much Nitrogen prevents proper bud formation and results in lower yields and airy buds. This means you should not use your vegetative or all-purpose nutrients (which are high in N) during the flowering stage! Nutrient bottles list their nutrient levels with 3 numbers. In the flowering stage, avoid giving plants too much Nitrogen (N) but make sure plants get a good source of Phosphorus (P) and Potassium (K). Dyna-Gro “Bloom” plant food, shown below, is an example of a flowering formula that has good ratios of N-P-K for the cannabis flowering stage. Any quality cannabis nutrients designed for the flowering are formulated to give your plants exactly what’s needed to produce buds. You can take out pretty much all of the guesswork out of nutrient ratios by using a cannabis-friendly “bloom” nutrient formula during the flowering stage. Examples of cannabis-friendly “Bloom” NPK ratios: Note: Avoid nutrients that are labeled “Grow,” “Vegetative” or “All-Purpose” in the flowering stage! In an emergency, if you can’t find specific Bloom nutrients, get cactus nutrients as they use a similar nutrient ratio as flowering cannabis plants. For those not using nutrients, starting with amended and composted super soil is the best way make sure plants get access to the nutrients they need at the right time. As a bonus, when starting with properly composted soil, it’s the one time you don’t need to worry about pH! 5.) Expose all buds to both high levels of light and a gentle breeze – each cola needs space to increase density to maximum levels! The most dense and weighty buds on the plant have a few inches of space to themselves and are exposed to both bright light and airflow. Buds hidden in the plant by leaves (without access to much airflow or light) stay airy and tend to never fatten up or become dense.
In fact, buds sitting in stagnant, non-moving air may stop developing completely. This is why you often see small buds on very leafy plants! Let me show you how much a difference it makes to expose buds to bright light and air.
Defoliation means removing leaves, and is an advanced technique that is not suitable for beginners . Defoliation should only be used on very leafy, healthy plants that are under bright lights.