To maximise nutrient uptake, aim for 10–20% runoff every time you water. Adopting this approach at an early stage should keep pH fluctuations to a minimum. However, it is especially vital if you are increasing nutrient concentrations for any reason (bloom boosters during flowering, for example).
Even if you know how to manage water-related issues, you still need to establish the best time to water cannabis plants. Timing goes hand in hand with the techniques listed above, varying according to the seedling, vegetative, and flowering stages.
Watering in the evening is an option, but the lower evening and nighttime temperatures can lead to a buildup of mould.
Water your plant until you notice runoff for 60 seconds afterwards. Now, use the same advice as above; wait until the topsoil has dried slightly to avoid swinging to the other end of the spectrum and providing too much water.
Overwatering cannabis plants is a very common mistake in novice growers. It’s usually the result of caring slightly too much and providing an excess of a key resource. For some growers, the sight of slight dryness in the topsoil is enough to induce panic. It looks as though their plant is about to dry out and die, so they proceed by drenching the soil with too much water, too frequently.
Consistency in watering routines supports another vital building block of cannabis—nutrition. Your plant’s root system will absorb essential nutrients from its growing medium, but only when pH levels are optimal (6.0–7.0 pH for soil, 5.5–6.5 for hydro/soilless/coco). The key is to keep plants watered on a schedule. Not only does it keep plants routinely hydrated, but it will prevent fluctuations in pH—a symptom diagnosed by brown spots on middle or lower leaves.
One key piece of cannabis anatomy is the root system. As well as anchoring plants securely into the soil to prevent the wind from blowing them over, the roots act to absorb water and nutrients from the soil below. A little-known fact is that plants also use their roots to take in oxygen. If you give your plants too much water, or the correct amount, but too often, you obstruct their ability to intake oxygen, which then results in symptoms arising.
The remedy for overwatering is quite a simple one: ease off on the fluids! First thing’s first, leave more time between watering sessions. Probe the topsoil with your index finger and wait until the first 3cm have sufficiently dried out before applying more water. This will generally lead to a routine of watering around every 2–3 days. Additionally, during watering, make sure not to drown your plant each time. Water enough to notice runoff leaving the drainage holes for about 60 seconds after watering, and no longer.
Seedling cannabis plants are particularly vulnerable, especially when it comes to watering—less is more at this crucial stage. Using a spray bottle, rather than a watering can, will help overzealous growers keep hydration under control. Give seedlings a light misting when the surrounding soil has begun to dry and your plants should flourish in no time.
Underwatering and overwatering produce similar symptoms and are both detrimental to plants. Learn how to manage watering correctly to avoid these issues.
1. Underwatered cannabis plants will look very weak, lifeless, and will show signs of wilting. Its no wonder they begin to look this way considering the vital role of water in plant physiology. The wilting of underwatered cannabis is different from the plump curling of overwatering – even if only subtly. Leaves will be fragile, brittle and even papery. They will look lifeless and drab. Another sign of an under watered cannabis plant an extremely dry growing medium, such as crispy soil.
Cannabis plants tend to thrive at a pH of around 6.5. To check your pH, simply test the runoff using a pH meter. Our pH tester by Hanna Instruments is super simple to use and offers fast and accurate readings. If your pH is either too high or too low, you can use pH regulators to bring it up or down.
1. One primary symptom of overwatering is drooping leaves. However, it is not the same kind of droop you see when underwatered – where leaves look wilted. It is the opposite in fact. Leaves are so full of water, that they are being forced to curl in on themselves. It results in them becoming very firm.
Too many fertiliser salts can obstruct nutrient uptake and cause wilting. Use the DiST 4 Pocket Conductivity Tester for accurate readings.
3. Another symptom of overwatering a cannabis plant is yellowing of the leaves. This is a sign of a nutrient problem, that is a side-effect of overwatering.
The truth is, there is much more to the watering process. Watering cannabis plants is a balancing act that takes some time and experimentation to perfect. Too much water can lead to some serious problems for plants and may obstruct oxygen intake. On the other end of the spectrum, too little water can lead to extremely dry conditions that will leave cannabis plants thirsty, eventually causing them to wilt.
Overwatering is an easy mistake to make when growing cannabis, and is most likely caused by worrying that plants need constant doses of water. It is a pitfall novice often fall into.
Paying close attention to your plants leaves is another way to tell if its time to water. Of course, waiting long enough to symptoms to arrive is not optimal, but any signs of wilting should immediately be followed by a dose of water.
However, there are telltale signs that will display it’s time to once again water your plants. Checking the top inch of soil is a promising way to identify this. Wait for this section of the soil to be dry before watering again in order to avoid overwatering. Once you have done so multiple times, you should start to figure out how long it takes in between each watering, and then you can go by that length of time instead.
We explore how to recognise and fix cannabis over and underwatering, as well as the importance of good quality water.