Autoflower Feeding Schedule

Plants need food like the rest of us. And just like us, knowing what food leads to what outcome within the body is essential. Cannabis plants have different nutrients that help power other systems within them, and these can typically break down into micronutrients and macronutrients. The three main components you’ll see contributing to the primary growth of a cannabis plant are Nitrogen, Phosphorus, and Potassium, commonly referred to as NPK.

Proper nutrient feeding is crucial to the growth and development of any cannabis plant, including autoflowers. A well-designed autoflower feeding schedule ensures plants receive the necessary macronutrients and micronutrients at the right time and in the right amounts. In this article, I’ll walk you through the best nutrient schedule for autoflowers and provide some tips to maximize the yield and potency of your autoflowering cannabis plants.

Feeding schedule for autoflowers

An autoflowering cannabis plant can typically do just fine without additives. Still, when you’re growing for yield, it’s best to try and optimize your plant’s growth with nutrients and a feeding schedule for autoflowers. Feeding your autos makes them healthy, quick-growing, and more potent. You can even provide specific inputs that enhance aspects of the plant, like sugars and terpenes. 

If you’re just learning about growing, you should download our Cannabis Grow Bible as well. It’s free and an excellent place to start learning how to optimize your plant care.

When to start feeding an autoflower plant? 

The best answer to how to feed autoflowers is not to start too early; around 1.5-2.5 weeks in, you should begin providing it nutrients. This can vary depending on your seedling’s performance, but it’s best to play it safe and wait till later so your plant doesn’t get a nutrient burn or lock up and stunt its growth. 

Knowing when to start feeding autoflowers is as vital as any other part of the growing process since this can make or break the rest of the grow cycle. Giving every nutrient to a plant five days past sprouting from seed could cause shock and hinder its growth for the rest of its grow cycle. It’s better to be safe than sorry about this, as feeding too early can cause stunted plants and minimized yields. You’ll want to start branching out from PH-balanced water around week 3. At that point, the plant has grown enough to harness and thrive from additional nutrients. 

How often should you feed an autoflower? 

One of the most common mistakes growers make happens when they start overwatering/overfeeding their plants. While it might feel like more water equates to yield with a plant, that’s far from the truth. Knowing how often to feed* autoflowers can affect plant health, size, stress, and yield quality. 

*When watering with nutrients, this is often referred to as “feeding” the plant. 

An autoflower feed schedule can be split into three stages: Seedling, Vegetative, and Flowering. Each step needs different nutrients to accomplish different aims, whether that’s to help with blooming, vegetative growth, or resin production.

Below, I’ve put together an autoflower feed chart to help guide you through your feed schedule:

Autoflower Feeding Chart
Week 0 (Germination)PH-Balanced Water
Week 1 (Seedling)PH-Balanced Water
Week 2 (Vegetating)3:1:1 (25%-50%)
Week 3 (Vegetating)3:1:1 (75%-100%)
Week 4 (Vegetating)3:1:1 (100%)
Week 5 (Pre-flowering)1:3:2
Week 6 (Flowering)1:3:2
Week 7 (Flowering)1:3:2
Week 8 (Flowering)0:3:3
Week 9 (Flowering)0:3:3
Week 10 (Ripening)PH-Balanced Water
Week 11 (Flushing)PH-Balanced Water

Seedling Stage 

At the beginning of an autoflowers life, it can be highly fragile since it’s actively growing out its uptake systems. Think of this like giving a newborn a steak to eat; maybe they need protein, but the delivery method is too harsh for their stage in life. As a seedling, cannabis plants need specially diluted starter nutrients; this helps bolster growth while making sure not to overwhelm the plant and shock it before it gets the chance to grow.

Once your seeding is growing and can handle receiving more nutrients, you can consider giving your seedlings a foliar feed to ensure you aren’t heavy-handed in your feeding. If you want to start with that feed after PH-balanced water, using a 3:1:1 NPK ratio helps spur root growth and chlorophyll production to kickstart your plant’s health and development.

autoflower seedling stage
Autoflower seedling stage

Vegetative Stage 

During the veg stage, the plant mainly looks for nutrients to facilitate growing stalks and spreading its roots. In vegetative nutrient feeds, Nitrogen is the main component of chlorophyll production and plant growth. To bring this back to human terms, think of this period like a growing teenager who can’t ever get enough to eat!

Like the seedling stage, you’ll want to use nutrients with an NPK ratio of 3:1:1 to help boost root development and plant growth. 

Vegetative stage of cannabis plant
Vegetative stage

Flowering Stage

Your flower stage is when you’ll move from feeding your autoflower for vegetative growth to feeding for bloom growth, focusing on the flowers and their secondary metabolites. Growing for vegetation at this stage will result in a high leaf-to-calyx ratio, which means less medicine and more harshness in your smoke.

A formulation of a 0:3:3 NPK ratio will aid your autoflower in creating robust, healthy flowers filled with your favorite cannabinoids. 

Will training affect the feeding schedule? 

Training will not affect your autoflower feeding schedule, though I recommend only using Low-Stress Training methods to maximize your yields. High-Stress Training isn’t a viable option with autoflowering strains since the shock and stress of super cropping and topping hinder plant growth.

You need autoflower seeds before you can begin feeding them! we have some of the most popular and easy-to-grow autoflowering seeds available. Click below to see our collection!

Bergman relaxing while plant grows

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Nutrient requirements for autoflowers

Now let’s look at the type of nutrients that autoflowers need. What are the best nutrients for autoflowers?

Macro and micronutrients 

When dealing with cannabis nutrients, they are typically divided between macronutrients and micronutrients, each adding value in a different area for the plant’s growth. The plant requires macronutrients in relatively large amounts, whereas micronutrients are needed in much smaller amounts.

Nitrogen, Phosphorous, and Potassium are macronutrients responsible for chlorophyll formation, root development, water regulation, and much more. Micronutrients like Iron, Zinc, and Copper act as enhancers to macronutrients, helping boost different areas of plant development that result in a more robust, higher-quality cannabis plant. Check out our guide if you’re looking for a more comprehensive overview of the best nutrients for autoflowers!

ILGM Pot type influences root zone and drainage for a cannabis plant
Pot type influences root zone and drainage for a cannabis plant

What does Epsom salt do for autoflowers? 

Epsom salt (also known as magnesium sulfate) is a combination of magnesium and sulfur, both of which help bolster cell wall growth and chlorophyll production. Think of Epsom salt as a booster to your plant’s other mechanisms for development, and it aids in making nutrients more bioavailable to the plant. Adding Epsom salt to your autoflower nutrient schedule can aid in plant growth and help maximize the short time you get to grow your autoflower.

Can you grow autoflowers without nutrients?

It’s entirely possible to grow a plant using just water. Although no plant NEEDS additional nutrients, it will produce a much smaller yield with potentially less potent flowers. Nutrients give your plant the best ability to grow to its full potential while optimizing its ability to produce both potency and yield.

Giving your plant only water is called flushing, a practice to remove excess nutrients from the soil to leave your plants with tepid water. The two times growers typically do this is at the end of a flowering cycle or if a plant has nutrient lockup and needs to be flushed to receive nutrients again.

flushing marijuana plants
Flushing a marijuana plant

Different types of nutrients for autoflowers

Organic vs. Inorganic

A common argument in the growing community centers around organic inputs versus synthetic fertilizers (nutrient salts). Some claim that organic nutrients produce better-quality cannabis, and others claim that the cannabis plant can’t tell the difference between either of the inputs since a nutrient is a nutrient. 

For synthetic fertilizer, the argument in favor of this method believes inorganic nutrients are cheaper and more convenient, and the control over what nutrients you provide to the plant is more precise and controlled than organic methods. For organic fertilizers, the argument in favor believes organic fertilizer reduces the chance of overfeeding, which causes nutrient burn. It also helps keep the biome within the soil intact, which helps produce a more efficient nutrient pipeline for the plant. 

Organic vs synthetic nutrients cannabis plant
Organic vs synthetic nutrients cannabis plant

Slow-release nutrients

An aspect of organic growing that’s celebrated is its slow-release nature. This means that nutrients from the inputs become available over time, which can pose a problem if your plant is nutrient deficient. Organic farming methods like Korean Natural Farming (KNF) and JADAM have developed strategies to deliver nutrient teas that aid in quick-release for nutrient deficiencies. 

Bottled nutrients

There are a lot of producers of synthetic fertilizer on the market, and most will tell you that they have the secret sauce that leads to 3-pound plants and the highest quality cannabinoids, terpenes, and flavonoids. Most give you those main three NPK components in varying amounts, typically with different additives.

If you’re interested in bottled nutrients, I highly recommend looking at ILGM’s line of nutrients, from seed to harvest; this will help you grow strong and healthy plants.

Cannabis Fertilizer

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Signs of underfeeding and overfeeding autoflowers

The cannabis plant is a visual organism that shows when it’s stressed or has nutrient deficiencies. Knowing the signs is half the battle to get your plant back on track to thrive. Depending on the severity, overfeeding and underfeeding can cause your plant distress and stunt its growth, affecting your end product.

Underfeeding occurs when the plant receives too little nutrition and can’t sustain its growth. Indicators of advanced nutrient deficiency are drooping leaves, yellowing leaves, and dry soil. Underfeeding also harms the plant’s immune system, making it susceptible to pests. Understanding a proper autoflower nutrient schedule helps keep your plants hydrated. 

NutrientUnderfeeding symptoms
 Nitrogen Leaves turn yellow, curled leaves and small leaves.
 Phosphorus Dark spots on leaves, curled leaves, slow growth.
 Potassium Weak branches, rusty color on leaves, slow flowering.
 Calcium Curling on lower leaves, slow flowering, yellowish-brown spots on leaves.
 Magnesium Dried out leaves, rust spots on leaves, sickly appearance.
Autoflower nutrient underfeeding symptom chart

Overfeeding occurs when the plant receives more nutrients than it can absorb and use, resulting in a buildup of excess nutrients in the soil that causes “nutrient lockup.” Similar to underfeeding, signs of overfeeding include burnt or yellowing tips of leaves, twisted leaves, and drooping leaves. Additionally, the plant may exhibit slow growth and poor root development, which leads to stunted growth and smaller yields.

NutrientOverfeeding symptoms
 Nitrogen Greener, darker leaves, curled or “clawed” leaves, weak branches, stunted growth, and less water uptake. If left untreated, leaves turn yellow or brown and will wilt.
 Phosphorus Yellow or dark veins on top leaves burned tips, thin and/or curled lower leaves, spots on lower leaves, micronutrient lockout.
 Potassium Burned and yellowing leaf tips, curling and spots on lower leaves, acidic root zone, micronutrient lockout.
 Calcium Stunted growth, drooping, and yellowing leaves. Red and orange spots may appear.
 Magnesium Dark brown or green leaves stunted growth.
Autoflower nutrient overfeeding symptom chart

Last words about feeding autos

Feeding schedules are an integral part of growing your autoflowers; knowing when to start, stop, change from nutrients to water for flushing, and knowing what nutrients you want to use makes all the difference to your plant’s growth. Macronutrients like Nitrogen, Phosphorous, and Potassium are the main elements that drive plant growth, whereas micronutrients like Iron, Zinc, and Copper are supplemental and encourage those same growth systems. Proper feed schedules and knowing how to dose your feeds properly can lead to high-yielding, potent, and healthy plants.

Caring for autoflowers differs from photoperiod plants in a few ways. Be sure to read our guide and let those babies thrive!

If you’re new to this, you will want to check out Robert’s Weed Grow Bible. You can download it for free and it has helped millions of budding growers over the past decade.

Happy growing!

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Mr Nigel Deez

Cannabis Cultivation Expert

Working in America's legal cannabis industry for the past 6 years, Nigel Deez bring various experiences to the table. Startin ... See profile

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