Nutrients And Growing Hydroponic Marijuana

Nutrient (or fertilizer) is food for plants. Marijuana plants need a certain amount of food in order to grow properly. The primary nutrients in plant foods are Nitrogen (N), Phosphorus (P), and Potassium (K).

In addition to nitrogen-phosphorus-potassium, marijuana plants require a lesser amount of secondary nutrients and trace quantities of other elements.

Secondary nutrients are calcium, sulphur, and magnesium. Trace elements are small quantities of boron, copper, molybdenum, zinc, iron, and manganese.

Plant foods are measured in an N-P-K format
N is Nitrogen
P is Phosphorus
K is Potassium

The percentage of the solution not used by nitrogen-phosphorus-potassium is secondary nutrients, trace elements, and inert material.

An all purpose nutrient with secondary elements like calcium, sulphur and magnesium and trace elements boron, copper, molybdenum, zinc, iron, and manganese will get you through all stages of growth. But during different stages of life, you can adjust the different nutrient levels needed at different times to optimize growth.

Regardless of the nutrient you choose, during the first two weeks of life and the first two weeks of flowering growth use half the amount (or less) of nutrient solution the manufacturer recommends for adult growth.

That is, if the nutrient package says to mix one tablespoon of nutrient to every gallon of water, you should add less than half a tablespoon of nutrient to every gallon of water for the first two weeks after sprouting and flowering.

This is not essential when flowering but it is for seeds and clones. Some marijuana growers don't add any nutrients to the water for the first two weeks. They then use a 50% solution for two weeks, then go to a 100% solution.

During vegetative growth the plants needs lots of N (nitrogen). They also need a fair amount of P (phosphorus) and K (potassium), 20-10-10, or 30-15-15, or something similar, with trace elements should do it.

During flowering the plants need more P (phosphorus) and more K (potassium) than they did during vegetative growth. It needs some N (nitrogen) but not as much as it did during vegetative growth. They also need calcium.

If you used:
--- something like 20-10-10 for vegetative growth, then try using 10-20-20 (or similar) for flowering.
--- something like 30-15-15 for vegetative growth, then try using 15-30-30 (or similar) for flowering.

If you can't find nutrients containing the proper combination for your needs (or you are not sure what kind of nutrient to get), look for a hydroponic nutrient recommended for growth when the plant is in the first stages of life and look for a hydroponic nutrient recommended for blooming (or flowering) when the plant is in the flowering stage. Make sure the nutrients you use contain trace elements.

Two and three part hydroponic nutrient solutions, that allow you to custom blend the amount of the different components, are recommended. But they might be costly. Organic hydroponic nutrients are available but they can be hard to find, and expensive.

Do not give your plants extra nutrients thinking it will make them grow faster. Too much will kill your plants. If you under fertilize, plants will take longer to grow but will not die. Follow the mixing instructions on your hydroponic nutrient package, if you aren't sure, use less rather than more.

As water evaporates and is absorbed by the plants, your water reservoir level will drop. Add tap water that has been aged 3 days or longer to the reservoir. I don't add nutrient solution to the water when I top up the reservoir tank, some people do.

Change the nutrient solution every 2 weeks. That is, discard the old solution and rinse off the reservoir, pumps, and other equipment that is used with hot water. After cleaning, add tap water that has been aged 3 days or longer to the reservoir then add nutrient solution.

You only need to clean the cups and tubing the plants are in before you start a new crop. The old solution that you are discarding can be used to water house or garden plants. This will at least double the growth rate if you usually water your plants with regular tap water.

Dry Powder vs' Liquid Nutrients

If you are buying nutrients, get the dry powder kind that you mix with water. They are much cheaper over the long run when you compare with already mixed liquid solutions.

Already mixed liquid solutions are just as good but many are primarily water and a good portion of the price you pay is to cover shipping water that you can add at home for free. There are some concentrated solutions that may be cost effective but I've always saved money using dry powder nutrients.

If you are using a hydroponic system that uses a pump to circulate water you will have to make sure the powdered solution dissolves fully before adding it to the reservoir. This is because any undissolved nutrient crystals can ruin a pump.

The best way to dissolve dry nutrients is to put some water in a cup, add the nutrient powder and stir. When you are sure that the powder has been fully dissolved, you can add it to the nutrient reservoir.

If there are any undissolved crystals left in the bottom of the glass you can add some boiling water then stir and let it sit for a day. After a day, stir it up again and add it to the reservoir, if there are still undissolved crystals in the glass, you can throw them out.

Whatever you do, don't add any solids that might damage a pump into the nutrient reservoir. Don't use any nutrients not specifically designed for hydroponic systems, that is, don't try to use nutrients designed for growing in soil.

Stop all plant food 7 days before harvesting when growing in a hydroponic garden. The last time you change the water in your reservoir, don't add any nutrients. You can repeat this water only 'feeding' several times in the 2 weeks prior to harvest. When growing in soil, stop all plant food 14 days before harvest.

This is so N-P-K and other elements can be removed from the plants before harvesting. This will insure that your weed doesn't taste like plant food and you are ingesting a minimal amount of N-P-K or trace elements. See when to harvest your marijuana crop for more info.

Grow Great Marijuana:
An Uncomplicated Guide to
Growing the World's Finest Cannabis

If you find instructions and books about growing hydroponic marijuana overly technical and hard to follow, this book is a very good choice for simple and accurate instructions. It does not cover advanced techniques so if you already know how to grow, this book would be of little value. But if you are a first time grower with no experience, this is the first book to look at.

It will explain the steps involved from start to finish (with text and images). Includes information on where to grow, type of hydroponic system to use, selecting a seed strain, lighting, fans, nutrients, security, clones, vegetative growth, flowering, harvesting, stress, pests, and more. Recommended for beginners only, this will show you everything you need to raise a hydroponic marijuana crop.

Marijuana Horticulture:
The Indoor/Outdoor Medical Grower's Bible

Over 500 pages with more than 1000 color images. If you were only going to get one book about growing, this book would be the best choice. Describes growing marijuana outdoors and indoors (with hydroponics or soil).

Also provides information that you can refer back to when things go wrong. A very comprehensive reference book for anyone interested in growing marijuana, either indoors or outdoors. Recommended for beginners and more advanced growers.

The Cannabis Grow Bible:
The Definitive Guide to Growing Marijuana
for Recreational and Medical Use

A very good source of information covering all aspects of growing, from seed selection to harvest, curing and more. Over 300 pages with almost 200 color and black-and-white photographs, charts, and tables. Recommended reference book for indoor and outdoor growers.

A great marijuana growing and breeding guide. Includes chapters on seeds, propagation and germination, growing indoors, growing outdoors, hydroponics, pre-flowering and flowering, predators, pests and plant fungi, breeding, and more.

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