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growing big cannabis plants indoors

Growing big cannabis plants indoors

A lot of growers ask me how to increase the size, number and density of their buds so they get bigger yields. The truth is, for most growers, the most effective way to increase bud size in the flowering stage is to increase LIGHT INTENSITY.

This is especially effective for those growing organically, as this works synergistically with the beneficial microbes in your soil

As a general rule of thumb…

Growing big cannabis plants indoors

Whatever school of thought you adhere to, it is vital that the cannabis plants receive enough nitrogen in the vegetative stage to grow bigger and stronger.

You must ensure your marijuana plants receive enough nitrogen (N), phosphorus (P), and potassium (K) at varying stages of the growth cycle. Typically, your plants need more nitrogen during the vegetative stage, and more phosphorus and potassium during flowering.

The Importance of Soil pH

Pruning, i.e., removing the small shoots between the trunk and branches, helps the marijuana plant develop huge buds.

If you want to grow bigger buds during flowering, you have to increase the amount of phosphorus and potassium you feed your marijuana plants. During the vegetative stage, the key macronutrient to boost the plant’s growth is nitrogen. However, when cannabis plants move into the flowering stage, it is essential to decrease the amount of nitrogen you feed them. Failing to do some can lead to problems like nitrogen toxicity. Some telltale signs of nitrogen toxicity are dark green leaves with yellow tips that curl downwards, weak stems, and slow plant growth.

Growing Bigger Buds – The Essentials

Experienced marijuana plant growers recognize the importance of nitrogen in the vegetative stage of the plant’s life. However, there are different schools of thought regarding how much nitrogen you should feed your cannabis plants. Some say that it is essential to provide higher levels of nitrogen than phosphorus and potassium during the vegetative stage. Others say that it is best to provide a feed that contains an equal level of each of these macronutrients, i.e., a N:P:K ratio of 20:20:20.

Growing big cannabis plants indoors

Intuitively, you might think that more nodes means more and larger buds, but this is far from the truth. Nodes with buds that are lower down on the plant away from the canopy will try to develop in flowering but will never become fully developed because they do not receive adequate light.

The GroBox can help grow cannabis plants in a small space. (Courtesy of GroBox)


If you want to grow big buds, you need to have big lights. When you identify the highest-quality cannabis in stores or dispensaries, you’re looking at cannabis where growers provided optimal indoor and outdoor lighting. You can’t cut corners when it comes to properly lighting your grow area. A basic guideline for lights is generally every 100 watts can cover one square foot. For example, a 600-watt light can cover a 6’x6′ area.


Once your plant switches to flowering, decrease your nitrogen levels and increase phosphorus levels to help the buds fully develop and become dense. If growing in soil, when switching from vegetative growth to flowering, top dress the soil with bat guano or worm castings as a great way to increase phosphorous levels while you liquid feed your plant other nutrients.