When To Stop Giving Cannabis Plants Nutrients

Cannabis Surrealism Art featuring a fox, volkwagon bus, and pot leaf in the woods.

When is the right time to stop giving your cannabis plants nutrients? We will discuss this and more in this blog so read on!

While your cannabis plants wouldn’t enjoy a cheeseburger as much as you do, they do still require nutrients. They can get nutrients from the soil, but this isn’t enough to maximize yield. If you want to get larger buds, you need to “feed” them.

Okay, the more nutrients the better, then- right? Not quite. Both over or underfeeding will negatively impact yields and can even kill your plants. That is why you need to know how often you should give your plants nutrients as well as when to stop giving cannabis nutrients. Let’s find out more right now.

Table of Contents

1. Should You Use Nutrients Every Time You Water Your Crops?

2. Nutrient Amount vs. Nutrient Frequency

3. When to Stop Giving Cannabis Nutrients

Should You Use Nutrients Every Time You Water Your Crops?

Unfortunately, there is no hard and fast answer to this question. It depends on many factors, including the size of your grow room, growing medium, and pot size. If you have a lot of plants to pack in a small grow room, you will use smaller pots and give the plants less time to grow. Bigger pots do not need watering as often. In this case, you may only water your plants once a week. You may even get away with doing so once every two weeks. In that situation, you would feed every time you water. In smaller pots, however, you may need to water several times a week. You could provide nutrients some times and alternate it with plain water.

Close up of cannabis leaves with water drops all over them.

Nutrient Amount vs. Nutrient Frequency

The frequency of feeding is not as important as the actual amount you feed your cannabis plants. You can feed often, but you then need to reduce the amount of nutrients you provide at each feeding. On the other hand, you can reduce the number of feedings, but you’ll need to increase the amount.

The easiest answer to get you started is to simply begin by following the plant nutrient schedule that comes with your nutrients. Watch your plants closely and adjust as needed. There comes a time, though, where you will withhold nutrients altogether.

Cannabis plants flowering in a cultivation facility.

When to Stop Giving Cannabis Nutrients

Whether or not your cannabis plant needs nutrients and how much nutrients to give are dependent on several factors, the most important of which is the stage of growth. Cannabis plants have vastly different nutrient requirements depending on their current stage of growth. Too much of one nutrient can hinder the absorption of another, leading to root rot, nutrient lockout, and more.

Seedlings won’t need feeding at all. As they grow and enter the vegetative stage, you will start them on nutrients. After you begin, you will gradually increase the dosage. They need a lot of nitrogen during this phase!

Once the plants enter the flowering stage, they need less nitrogen and more potassium instead. For the best results, keep increasing the amounts of nutrients until the very end of the bloom stage. 

Anywhere from five days to two weeks prior to harvest you will stop nutrients and start to flush the plants with only water. Ending feeding will depend on many factors, including what medium you are using. When you are using soil it’s recommended to stop nutrients and start flushing at a week and a half prior to harvest. Rockwool or coco are best starting at a week. If you are using hydroponics, stop nutrients at five to seven days before harvest. Typically there are nutrients still left in the medium that the plants will use during this stage.

It is not recommended to flush plants when growing in amended organic soil. You have developed a delicate ecosystem, and flushing the soil too much can damage it. 

The amount of flushing is completely up to the grower. Be sure to use pure reverse osmosis water. This helps to remove the mineral deposits still in the medium. You can choose to water the plants the same amount you did prior to bloom, or you can do it periodically. Just be sure to not over water during the plant’s final stage. Following these guidelines can result in big, healthy buds.

Here at Eden Water Tech, we take the guesswork out of cultivating cannabis. We can design custom on-demand fertigation to assist new growers with basic operations or help elevate the experienced growers to the next level. Reach out to learn more!


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