When should you start feeding your cannabis plants fertilizer

When to start feeding your cannabis nutrients

Hello growers! Let’s learn about feeding our plants their first dose of nutrients.

Cannabis needs 4 things to grow well. Light, carbon dioxide, water, and nutrients. Leaves are responsible for the first two, while the roots focus on acquiring water and nutrients.

When seedlings are first planted, they have enough stored energy to unfurl their first set of leaves (cotyledons) and begin driving a tap root down through the soil.

Marijuana seeds are dicotyledonous. The seedlings will acquire energy through a process that breaks down food material stored in the endosperm of the seed. Here, the seedlings have plenty of energy and don’t need any addition of nutrients from fertilizers right away. The role of creating energy is assumed by its cotyledons or baby leaves.
Once your seedlings have used up all their energy, they will require nutrients from an outside source. This is where the grower comes in and gives the plant its first feeding of nutrients.

Lets talk about when is the right time to start feeding your cannabis plants and how to give them their first dose of nutrients.

When to start feeding your plants Reefertilizer nutrients

Once your plants have grown 3-4 sets of true leaves, you can give them their first feeding of nutrients.
It usually takes about 3-4 weeks from planting your germinated seed for your seedling to have used up all the energy left in the seed. Your plant roots are now taking nutrients from the soil and from any added fertilizer. The cotyledons or “seed leaves” might start to turn yellow around this time.

This is also the time I like to transplant the plants to a larger pot. After the transplant, I will give them their first low dose feeding. This is day one of the vegetative stage.

If you’re using Reefertilizer Grow, a low dose is 5ml for 4L of water or a ¼ teaspoon for 1L of water.

The size of your planter will determine the volume of nutrients you need to give each plant. You want to give them enough water/nutrients that there’s some runoff from the bottom of the planter. A rule of thumb is to have 20% runoff. So let’s say you feed your plant 2L of nutrient solution, there should be about 400ml of runoff.

The runoff will help guarantee that your soil is completely saturated. Another trick growers do is pre-water their soil 30 minutes before giving them nutrients. This also helps your soil absorb more water.

As your plants grow they will suck up water and nutrients at a faster pace.

Transplanting cannabis first feeding

This plant was transplanted, topped, and given its first low dose feeding. This was “Day 1” of veg.

This is the same plant 9 days later. It is getting its second feeding.

How to feed your plants nutrients

Mixing fertilizer with water and feeding your plants is a simple process with a product like Reefertilizer. First, you will want to know how much water you will need for your pots. 2 liter of water per plant in a 5 gallon planter is a good place to start.
You want to give them just enough liquid that you get runoff from the bottom of the planter after watering. This ensures that the soil is completely saturated and nutrients aren’t being wasted.

In this demonstration, we will be feeding 1 plant its first low dose of nutrients.

Are you using tap water?

The quality of tap water can vary drastically from one city to the next. Tap water may contain any number of minerals and chemicals. Most of these are in trace amounts and shouldn’t negatively impact the health of your plants.
Chlorine is one chemical found in most tap water, it won’t harm your plants, but it might damage living organisms in your soil. You can easily remove chlorine from your water by letting it rest uncovered overnight. The chlorine will eventually evaporate out of the water.

Let’s take a look at the Reefertilizer feeding schedule to find out how much nutrients I need to mix to feed my plants.

Cannabis feeding chart
measure the correct amount of reefertilizer nutrients

Measure the powdered cannabis nutrients and dissolve them into a small amount of water first.

pH your water after adding Reefertilizer.

Check that the pH of your nutrient solution is in the correct range.

Feed your plants. This plant is on its second feeding.

I have one plant in a 5 gallon fabric pot and I want to feed it 2L of nutrient water. According to the chart, I will need to mix 2.5ml (1/2 teaspoon) into 2L of water.

Fill a jug with 2L of water.

In a small cup, add 2.5ml of Reefertilizer Grow.

Use some water from the jug and mix it with the powder. This will help the powder dissolve quickly. By using a small jar with a lid and warm water, you can shake it up so the powder dissolves even faster.

Pour this liquid back into your jug and give it a good stir.

If you have more than one plant, you will need to make a larger batch using the same nutrient to water ratio. Best to do a big batch and adjust the pH when done.

At this point, you should pH your solution with a pH pen. We have one available in our store.
Cannabis grown in soil likes a pH in the range of 6 and 6.8. This makes sure that the nutrients are chemically available to the root system.

You may need to use a product like pH up or down to adjust the pH (Amazon link). Natural products like citric acid (lowers pH) and sodium bicarbonate (raises pH) can also be used to adjust the pH as well.

You’re now ready to feed your plants!

Water around the base of your plant and move outwards.

Don’t just pour water into one spot. If you do the water will make a hole through your soil and your pot won’t be evenly saturated.

I like to use a watering can with a long neck for more control. Avoid getting water on the leaves, they are young and easily damaged.

That’s it for your first feeding. In about 24 hours you will see a lot more growth from your plant. This means the nutrients are working.

Increasing the level of nutrients

Water your plant as needed, when the first top inch of soil is completely dry. For a plant this young, it might not need another watering until a week from now. Its root system is still small and won’t be able to suck up all that water just yet. The temperature of your grow area will also affect how often you need to water your plants.

Every week after you will feed your plants a higher dosage of nutrients. As your plants get bigger, they get hungrier for more nutrients and water.

Thanks for reading this article. I hope it helped you a getting started feeding you plants their first dose of nutrients. If you have any questions or suggestions on how to improve this article, leave a comment below.

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