There are many factors that determine when to water your plants such as grow room temperature, amount of ventilation, humidity levels, type of growing medium used to name a few. One method is to use the single probe Rapidtest moisture meter available from most of the major garden centers for under $20. This meter reads without using batteries. It is invaluable asset in helping to determine overwatered conditions and uneven moisture distribution within the container.

MOISTURE METERS

A moisture meter can be inserted at various depths to accurately assess conditions. It is best to have the highest moisture levels at the very bottom of your container, with less moisture in the middle and the least on the top portion. This encourages the roots to grow down towards the bottom and makes for better plant developement.

WET/DRY CYCLE

It is a good idea to always maintain a certain amount of moisture in the roots. Growers that allow their medium to dry out to the point at which the leaves "droop" are reducing their final yields and compromising quality. Fertilizer salts concentrations can dramatically increase as the water dissipates which can cause the roots to become repeatedly stressed going through extreme "wet/dry cycle". The plant is being deprived of moisture that would be available to fuel additional growth and suffers.

pH

The pH range is the degree of acidity or alkalinity in your water. Marijuana needs a slightly acidic environment to grow properly. The suggested pH range for watering marijuana in soil should be between 6.0 and 6.5. In hydro this range can drop to as low as 5.5. It is VERY important to ensure that the water you are feeding your plants with be in the correct pH range else the plants will not be able to properly utilize their nutrients. Severe pH problems will cause the plant to simply stop growing and can lead to its demise if not dealt with quickly.

You can adjust the pH of your water both up or down with the addition of the right chemicals which you can find at any aquarium store.

FILTERED WATER

The most common problems with using tap water for watering cannabis plants will be pH usually caused by lime or calcium in the groundwater supply. Elements dissolved in the tap water may cause lockups where the plant will not be able to absorb the nutrients it needs leading to deficiencies.

Most growers will use a water filtration system for filtering their water. This can be as simple as running your tap water through a Brita water filter or the more elaborate reverse osmosis systems. Under sink models can be purchased at any home improvement store for around US$100. They will require filter replacement about twice per year depending on usage. The typical model can clean 50 gallons of tap water down to 0 ppm and pH 6.0.

CHEMICAL FERTILIZERS

The most common fertilizers used in cannabis cultivation are:

20-20-20 / Used in vegetative stage
10-60-10 / Used in flowering stage
0-52-34 / Used in late flowering stage

These are fertilizer salts that dissolve quickly in water and are taken up by the plant immediately. They are easy to measure and very inexpensive to purchase and last forever. They provide fabulous results both in yield and potency provided you have followed the manufacturers directions for mixing.

A good flushing of pH adjusted water the last 7 to 10 days before harvesting will bring out the flavour and aroma of your buds!