HOW TO

water cannabis plants in soil

What's the best way to water cannabis in soil ?

It's a commonly asked question by new growers which this guide will help answer by understanding how watering works for cannabis plants and how to provide the best for your plants for top quality buds.

Water brings nutrients and minerals to your plant that will be absorbed by roots. Even if watering a plant can sound easy it is one of the most important step in growing marijuana. Giving not enough or too much water could damage your plant and ruin your harvest.

Over and under watering are common mistakes that can lead to diseases and deficiencies.
This guide will help you to understand your plant needs and avoid unforgiving mistakes.

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Ninja Grow Bundle BY SuperGreenLab

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#1

How to water

The way you water your plant will depend on many factors such as growing medium, size of the pot or the stage of your plant. This is not an exact science but more like a feeling. If you feel that your plant is thirsty then it's time to water.

We recommend watering your plant in a pot saucer or in your bathtub then moving it back in your grow space.
Having aerated pots such as fabric pots or air pots is also recommended, it will prevent mold and pest issues.

The best time to water your plant is in the morning, when your lights turn on. Watering this way will help prevent mold or fungus issues.

The way you water you plant will primary be based on your plant growing stage.

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#2

How to water: seedlings

Obviously they will need much less water than an adult plant, you must water your seedling gently using a small amount of water to prevent damaging the plant or the roots. It is recommended to put your seedling in a smaller pot (like a solo cup) to avoid over watering.

You'll need to moisten the substrate but do not soak the soil or it will slow the growth of the plant and overwater the roots. You don't need to add nutrients during the 2 first weeks since sprouting, the seed has nutrients stored or the initial growth.

If you feel like it or you need to raise your grow space humidity you can spray water on the leaves. But we recommend to not spray water with nutrients and to spray it before your lights turn off, watch out not to light burn or harm your fragile plant.

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Peat pellets BY Jiffy

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Simple germination tool and easy transplant without the risk of shock.

Simple germination tool and easy transplant without the risk of shock.

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Light mix 50L BY Biobizz

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Keep it simple, no extra nutrients added in the soil.

If you want more control, Light·Mix provides the ideal foundation for encouraging vigorous growth in

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#3

How to water : mature plants

Mature plant will require more water, but don't drown it.

Your medium must drain water properly and don't hold water back in the pot, growing in a too moist medium can lead to a lot of root and fungus problems. Growing medium will also affect how much and how often you will water your plants.

For the soil we do recommend using light mix, which has low nutrients and good drainage. As soilless and hydro have different watering techniques we will focus on the watering basics with soil.

You can still spray water on the leaves during vegetative stage but watch out not to do it once your plant has entered the flowering stage, it would lead to bud rot and you'll lose your harvest.

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What you'll need

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Light mix 50L BY Biobizz

From amazon.de

Keep it simple, no extra nutrients added in the soil.

If you want more control, Light·Mix provides the ideal foundation for encouraging vigorous growth in

€14.99

*price may vary incl. tax
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Clay pebbles BY GROW!T

From amazon.com

Extra drainage and protection from water left in saucer.

Clay pebbles are lightweight and porous balls that are mixed with your soil, they hold air in them a

$25.97

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#4

Importance of PH and Nutrients

Except if your growing in organic soil, PH is probably the most important thing to check.

Cannabis roots does have a certain range of PH where they are able to absorb nutrients. Giving water with nutrients but the wrong PH will lead to a nutrients lockout, your plant will not take the nutrients you feed it.

Now that you've heard about PH, it's time to present nutrients. There is a lot of different and good brands on the market. Most of them are fine and will provide good results. We could make a whole guide presenting each types of nutrients and their pros and cons. As each brand have different feeding charts and tips the only thing you need to know here is that you'll need to add those nutrients to your water to feed your plant and provide the best soil conditions.

We do recommend using Biotabs nutrients as they are organic and will exempt you controlling PH.

Not adjusting your water PH is a common beginner mistake that will impact quantity and quality of your buds.

PH control is super easy and won't take you this much time.

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pH meter BY Earabella

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For optimal nutrient intake

Because pH affects the plant's nutrient intake, it's essential to be in the correct range. How do yo

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pH down BY General Hydroponics

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Reduce pH for optimal nutrient intake

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#5

How to adjust your water PH

In soil, the right PH is between 6.0 and 7.0, the best is to stay in this range and vary your PH value at each watering.

You can refer to the chart to see which nutrients are consumed at which PH level.

Now, to test your water PH we recommend using a PH pen. Just remember you'll need to calibrate your PH tester every 1-2 months to keep precise measurements.

If your PH isn't in the range, too low or too high you'll need to add few drops of PH up or PH down solutions until you got the right measurements. Stir and wait a couple minutes for the PH to stabilize before measuring.

Remember that PH don't need to be exact as long as you stay in the right range.
Also make sure you check your water PH after you added your nutrients, so they will not impact the measurements.

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What you'll need

Selected region:
World
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pH meter BY Earabella

From amazon.com

For optimal nutrient intake

Because pH affects the plant's nutrient intake, it's essential to be in the correct range. How do yo

$12.83

*price may vary incl. tax
ADD TO CART

pH down BY General Hydroponics

From amazon.com

Reduce pH for optimal nutrient intake

$14.93

*price may vary incl. tax
ADD TO CART
Show all items - (3 items)
#6

How much water

The amount of water you should give to your plant will also vary and will depend on :
Pot size
Box environment (temperatures, ventilation, humidity...)
Plant health and stage of growth

A good way to determine how much water you should give per plant is to base your water volume on your pot size. You must water the quarter of the total volume of your pot.

5L pot = 1,25L of water
10L pot = 2.5L of water

This is not the perfect dosage as you should base your calculations on many other points, but it's good enough to prevent over/under watering and cover your plant needs.

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#7

How often

Now that you're aware of how much water you should give to your plant, let's talk about when to water.

Whether you add nutrients, you check PH and you water the right amount. If you don't know when to water and do it too often or not enough you'll definitely end up with deficiencies or overfeeding issues.

The main point when watering cannabis is to let the soil dry out before each watering. Cannabis don't need and don't like continuous irrigation, you must water less often but in good quantities.

Here are two tips to check if your soil is dry enough to water again :

  • Stick your first knuckle in the top soil, if it feels dry then your good to water again
  • Weigh your pot, if it feels light. This tip is more accurate but require a little more experience.

You plant can also give you signs that she is thirsty :

  • Droopy yellowing leaves : Leaves will tell you that your plant need water, she will appear weak and sick. However under watering symptoms often look the same as over watering, leave will also appear droopy when over watered. When over watered, leaves will looks more soggy and heavy. Keep in mind that if your soil is dry af, it is under watering. If your soil is still moist then it's probably over watering.
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#8

Different types of water

The quality of water you're using does have an impact and all waters are not the same. Water can contain a lot of contaminants, some are good and there is chemical contaminants as chlorine, calcium... No matter what type of water you are using, you must check PH and PPM to know it's quality. Neutral water come with a PH of 7, PPM indicate the percentage of contaminants. If you want to learn more about PPM, check the link below.

Now let's present water sources and their pros and cons.

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#9

Tap water

It's the cheapest and the most accessible option.
Tap water quality will depend on your location, in larger cities the water tend to have a high level of chemical contaminants. Too much of those can affect biological organism.
A tip to get rid of chemicals in your water is to let it sit open, in a dark place for a day or two before watering.

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#10

Bottled water

Bottled water is good for your plant as long as it contains minerals to feed them, but you must keep in mind that it does have a big environmental impact. This option is kinda expensive and non ecologic friendly.

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#11

Rain water

Using a water collection system is a cheap and environmental friendly option. Rain water catchers are pretty good but take up quite some space, you'll need a garden to install this kind of system.
However, you'll have to to filter and stock your rain water properly using dedicated filters and storage containers.

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#12

Reverse Osmosis (RO) water system

This is probably the best option in terms of water quality, RO systems will filter and decontaminate large water volumes. A perfect match for growers.
The cons of this option is the initial cost of the installation : It cost about 100$.

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Next

GROWING 101 - GERMINATION

Germination is the first step when starting from seed :)
This guide will teach you how to successfuly germinate your seeds with a battle tested method; the shot glass.

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