CANNABIS NEWS UK

EDUCATION WELFARE SERVICE

​WATER FOR YOUR CANNABIS PLANTS

Watering your cannabis plants is an essential part of the growing process. It is however, very easy to get wrong and can result in over or under watering your marijuana. Understanding just how much your cannabis plants need is something that comes with time and experience, especially if you continue to grow the same strain over and over. The following information should hopefully go some way to broaden your knowledge and make this learning curve a lot easier.How much you need to water your cannabis is going to come down to a myriad of factors. Things like the age and strain of the plant, the temperature of the room, the medium you are using and the intensity of the light are all going to play a part in exactly how much and how frequently you need to do it. Because of this there is no real definitive amount of water to give them, you will need to assess the situation within your grow room and make a call. Of course, the best indicator is going to be the cannabis plants themselves; you just need to know what to look for.


HOW SHOULD YOU WATER YOUR CANNABIS PLANTS
A  great way to water you cannabis plants is by bottom feeding. This method will give you a good indication as to how much water your plants need.  Place your plant pots in a tray of water, if your plant pots have holes in the bottom (which they should), water will be absorbed upwards towards the roots. Your roots absorb water through the process of osmosis; they try to reach equilibrium between the water content outside and inside the root. As it reaches this equilibrium of contentedness, absorption will slow down, if there is still water in your tray/plate after 30 minutes then remove it, your cannabis has enough. If there is not any water left then add a bit more and see if it is absorbed. Feeding from the bottom encourages your roots to grow downwards in search of more water, it promotes healthy growth. You will find most people nowadays water from the top, but real, old-school growers always did it from the bottom.
It is important towards the end of your cannabis' life cycle not to over water; especially if you are doing a pre-harvest flush (see our article on flushing). It is an easy pit to fall into, just make sure to replace the watering cycle with the flushing. Do not do both.


SO, HOW FREQUENTLY SHOULD YOU WATER YOUR CANNABIS PLANTS?
Well, as mentioned, this can vary depending on a lot of factors. The standard routine is to water every second or third day, but the best method is to assess the situation yourself and water as needed. There are a couple of tests you can perform to see whether you cannabis needs more water.
Firstly there is the finger test. Simply place your finger into the soil and see how dry it is, if it is damp then hold off, but if it is dry then add some water. This should now make the soil damp for a couple of days (unless your grow room temperature and lights are very intense and dry it out quickly). Simply keep an eye on the soil and keep it topped up whenever it dries out. Do not put more water in when it is damp.The next test is to pick up and feel the weight of you pot. When there is water present the pot is going to be a lot heavier than usually. To get an effective idea of base level, fill a same sized pot with your grow medium and feel its weight, now compare this to a recently watered plant. This difference should give you an idea of when all of the water is gone from you soil.As previously mentioned, the amount and frequency of watering is going to depend on a lot of factors, but try to minimize the extent and variation of them. For example, use the same sized pots for all your plants, make sure you have an even spread of light and that you have a uniform temperature throughout your entire grow room, (within limits of course, try to make things as uniform as possible).


WHY IS IT DANGEROUS TO OVER WATER YOUR CANNABIS?
If you consistently over water you weed then it will eventually die. This will mainly be because you do not give the roots the opportunity to obtain oxygen. In the case of your watering cycle, when the soil is slightly damp/almost dry it allows air to circulate within the soil and roots. Roots require oxygen from the air for their cell respiration. If they are denied oxygen for too long due to the soil being too wet then the cells in your roots will die, leading to the eventual death of the plant. If the roots are damaged your cannabis cannot take water and nutrients from the soil, it will stop growth and eventually kill it.Another reason plants die from over watering is because it causes root rot. If roots cannot dry out they become prone to rot and die, thus killing the plant.


WHY IS IT DANGEROUS TO UNDER WATER YOUR PLANT?
Quite simply, water is the basis of plant life; it is required for structural integrity, the production of food (photosynthesis), and the uptake of nutrients. Without it they will die - exactly the same as any other living thing would.


HOW CAN YOU TELL IF YOUR PLANTS HAVE BEEN OVER OR UNDER WATERED?
The best indication of over or under watering can be obtained by monitoring the cannabis plants' leaves. Watch your plants for a few days after watering them. If the fan leaves point upwards towards the light then they are fine. If they are drooping or wilting downwards then this may be an indication of both potential over and under watering. In the case of over watering the leaves remain looking healthy and firm, but curl downwards due to being packed to the limits with water. If the plants have been under watered then the leaves will be wilting and appear weak and frail, drooping down as they have no water to support their cell structure.