How should you water cannabis in coco? This is one of the most frequent questions that we get. We argue that high-frequency fertigation is the best way to water coco. But, how much, how frequently, and what do you pay attention to? This coco watering guide answers all your questions about high frequency fertigation and how to water cannabis in coco. I provide specific advice about how much water for each event and discuss how to determine your coco coir watering frequency. I include a coco coir watering schedule to help you set the timing of multiple daily fertigation events.

Dr Coco’s Guide to Feed and Water Cannabis in Coco

This article is part of Dr Coco’s Guide to Feeding and Watering Cannabis in Coco. Be sure to read the complete series!

• Growing Cannabis in Coco Coir with High Frequency Fertigation
• Understanding EC, PPM & TDS for Growing Cannabis
• How to Water Cannabis Plants in Coco Coir
• EC/PPM Targets for Fertigating Cannabis
• How to Mix Nutrients for Cannabis
• How to Manage Cannabis Fertigation by Measuring Run-off EC/PPM

Feeding and Watering is "Fertigating"

When we water plants in coco, the water should always include nutrients. The technical term for this is fertigation, which simply means combining fertilizers with the irrigation water. Proper fertigation strategy is the key to getting the best results from your coco grow. In “Growing Cannabis in Coco with High Frequency Fertigation”, I lay out 5 key principles. In this guide, I explain how to put these principles into action.

Principle 1: Fertigation is a Balance: Proper fertigation strategy balances the Nutrient Element Ratio (NER), which controls plant nutrition and the Electrical Conductivity (EC), which controls osmosis.

Principle 2: Always Add Fertilizers to the Water: To maintain the balance between NER and EC, nutrients must be added to all irrigation water at the correct ratios and doses. The feed chart determines the ratio, and EC determines the dose. See our guide, "How to Mix Nutrients for Cannabis".

Principle 3: Keep the Coco Wet: Do not let your coco get dry! One of the key benefits to growing in coco is that it enables high frequency fertigation. This article discusses just how frequently it should be.

Principle 4: Run-off is Critical: Run-off carries away the excess salts and allows you to maintain a consistent root zone EC. Proper run-off practices are discussed below.

Principle 5: Manage Electrical Conductivity (EC): You need to monitor the EC of the nutrient solution you are adding (inflow) and the EC of the water that drains through and ends up in the saucer of each plant (run-off). As discussed in our tutorial “How to Manage Cannabis Fertigation by Measuring Run-off EC”, The critical number is the difference between the two. As explained below, fertigation frequency is one of the main ways that you maintain that difference in the acceptable range.

Coco Coir Watering Guide

This coco watering guide explains in detail how to put the principles of high frequency fertigation into action. It explains:

• The basics of watering cannabis in coco.
• How much water you need to apply.
• How to determine your coco coir watering frequency.
• The best coco coir watering schedule.
• And, how to handle run-off water.

Watering Cannabis in Coco

Many growers are concerned about watering because of their experience with soil. Happily, coco is not soil and it is a lot easier to know how and when to water in coco than in other media. There are a few basic rules for watering the plants and they can be mastered quickly.

Ensure Complete Saturation

Every time you water cannabis in coco, you should saturate the entire volume of the media. Remember that even at the seedling stage there is no real risk of over-watering. Properly conditioned coco retains adequate oxygen for the roots even when it is saturated.

Saturation is important to prevent salt build-up in the media which can burn your plant. The water that moves through the media and ends up as run-off is the mechanism that prevents salt build up. If the media is not saturated, then there is no water moving through it and salts accumulate.

Water Quantity is Determined by Run-off

The number one rule for watering coco is that you should always provide enough nutrient solution to each plant to produce 10-20% run-off. That means that if you add one quart of water then 10-20% of that quart should end up as run-off. Run-off water plays an important role in maintaining healthy conditions in the root zone. Therefore, you need to always get run-off no matter how much water you must add in order to accomplish that.

Under high-frequency fertigation, the quantity needed to produce run-off should be small. As I explain in “Growing Cannabis in Coco with High Frequency Fertigation”, it is ideal to keep the coco between 90 and 100% saturated all the time. Therefore, when we water in coco, the coco is already 90% saturated and it cannot hold much more. As discussed further below, the ideal quantity of water per event is about 5% of the volume of the growing container. This is ideal, but the rule is that you need to always provide enough water to actually produce adequate run-off from each plant.

Hand-Watering vs. Automatic Watering for Coco Grows

Many growers are concerned that high frequency fertigation is only possible with an automatic watering system. However, it is possible to unlock the benefits of high frequency fertigation with only watering once or twice per day. Therefore, it is possible to get tremendous results from coco when hand-watering, but it requires a significant commitment.

Automatic watering systems are preferred because they make it very easy to manage your grow. Not only do they make it easier, but they allow you to set the best frequency and timing for the plants. Automatic watering is less expensive and easier to set up than most growers think. We have a complete series of articles and tutorials for setting up and running your Automatic Watering System.

The Coco for Cannabis Guide to Automatic Watering