When to Start Feeding Your Cannabis Flowering Fertilizer

Cannabis is an interesting plant: it’s both extremely hardy and extremely demanding of growers. It’s a weed that grows in ditches all over the world, but it also requires a lot of time, effort, and attention from growers in order to grow to its full potential.

This applies to every aspect of growing – the soil you use, the environment in the grow room, the lighting, the blend of nutrients you feed your plants, and more. The nutrients in particular can be complicated because over the course of your plant’s life, its dietary needs will shift. The biggest shift happens during the flowering phase, but how do you know exactly when to switch to flowering fertilizer.

Reefertilizer Bloom Nutrients for Flower

Reefertilizer® Bloom
Nutrients For Plants in Flower

 Fast-Acting Bloom Nutrients with CalMag
For Indoor and Outdoor Grows
Easier To Measure, Mix, & Feed
Fast 1-2 Day Shipping CAN + USA

$27.95 CADAdd to cart

The Reefertilizer Grow Kit Is Our Simple All-In-One Solution To Growing Great Weed With Less Waste | Learn More

When to Switch to Flowering Nutrients

The growth of a cannabis plant can be broken down into two basic stages: the vegetative stage and the flowering stage. You will need to pay close attention to your plants to know when to switch to flowering fertilizer at the beginning of the flowering stage.
Plants will have a short growth spurt then stop growing taller when the flower period begins. At that point, they’ll be focusing all of their energy on growing bigger, juicier buds. Typically, this happens around three weeks into the flowering stage.

Indoor – When you switch lights to 12 hours of darkness a day the plant will naturally go to a flowering state. A week after the switch is when you should start feeding plants Bloom fertilizer.

Outdoor – Plants will normally begin to flower a few weeks after the summer solstice (June 20) as the days begin to get shorter. Look to the formation of flowers as a sign to switch to Bloom fertilizer.

Autoflowers – These types of strains will flower automatically no matter how much light they’re getting daily. Autos typically start flowering after 3-4 weeks. Keep an eye out for new flowers and switch to Bloom fertilizer.

Early signs of cannabis in flower

Click the image above to see a close up of the very early stages of flowering.

Those small white “hairs” are called pistils. The pistils emerge from a little pod called a calyx. The cannabis flower is made up of a cluster of these calyxes.

Reefertilizer Bloom Is the Right Blend For Cannabis If You Want Large Flowers And Amazing Terpene Production | Learn More

The Best Flowering Fertilizer for Cannabis

Reefertilizer Bloom being used to grow flowering cannabis plants outdoors

During the flowering stage, your plants will need more phosphorus and potassium and less nitrogen. At Reefertilizer, we use an NPK mix of 20-5-10 while our plants are growing, and switch to a 5-30-20 blend at the appropriate time. It’s always a good idea to research the specific nutrient requirements of your current strain before you start fertilizing! Some strains require less nutrients than others, and will get nutrient burn more easily if you overdo it. For example we recommend going with slightly lower nutrient doses when growing auto flowering strains.

Finally, remember to stop feeding your plants nutrients for the last week before harvest to flush them out. This should help get rid of any excess nutrients in the soil so the plant has time to metabolize the nutrients stored in the plant. This helps the final flavor to be as smooth as possible. Happy growing!

If you want to learn even more about growing good cannabis, we offer a free 40+ page guide full of images.
Now available on Amazon.
Sign up for our newsletter and download the digital copy today!

Beginners guide to cannabis cultivation

This guide will answer many questions about growing cannabis, like the following...

Selecting Seeds
Identify and Correct Problems
Maximize Yield
Much More...

Get a Chance to INSTANTLY WIN a Reefertilizer Nutrient Kit When You Sign Up.

 

 

Get a Physical Copy Of Our Grow Guide On Amazon