For the majority of your time growing cannabis, the most labor-intensive process is watering. For weeks at a time, your plants don’t need much more intervention than keeping a regular light schedule and watering frequently. Once you have more than a few plants, watering can start to take up a lot of your time every week. Watering by hand isn’t the only option, though. There are several other methods that allow you to take a step back and save time every week.
There are a few methods available to water your plants. Some are more labor-heavy than others. The real limiting factor is how much time and money you’re willing to spend upfront. If you have a larger budget or a lot of free time at the beginning of your grow, you can save hours of your time over the course of the crop.
This method is self-explanatory. With hand-watering, you fill up your watering and go around watering each plant. This method is fine if you only have two or three plants, or if you’re very particular about how much water each plant receives. The problem with hand watering is that you have to spend so much time doing it. It also takes work to make sure each plant gets the same amount of water. You have to pay attention to make sure you aren’t distributing water unequally.
Automatic Watering Soil
Drip watering is the simplest method of automatic watering. You set up some hoses, a water reservoir, a pump, and a timer. The hoses are the trickiest part because you want to make sure every juncture is waterproof. If you have your light set up to work automatically or you’ve installed ductwork for your grow, you have the essential skills to set up a drip watering system.
There are three basic methods of watering cannabis in soil. First, you can use a bottom-feeding system, where the hoses expel water into the tray on which the cannabis pot sits. The water then is absorbed up through the bottom of the pot into the growth medium. This doesn’t work well if you’re adding fertilizer to your water, because most of it won’t make its way up to the plant.
The second two methods are more effective for fertilized water. Drip-feeding systems use small feeder hoses with many little holes along the sides. These are laid across the soil, so water is equally distributed around the plant. Drip hoses are easily added after the plant has already grown relatively large.
The second method, halo watering, is very similar. A “halo” plastic tube with many small holes is placed around the seedling when it is still small. This halo is connected to the watering hose and remains in place for the duration of the grow. Halos ensure even water distribution where drip hoses can be more easily bumped out of place. However, halos are usually more expensive than drip tubes, and can’t be placed once the plant is bigger than the halo is wide.
A hydroponic system takes automatic watering to the next level. Hydro systems flush plants with water and nutrients in an inert growth medium. The simplest hydroponic systems are scaled-up automatic watering systems. However, they quickly become more complex to the point that they become entire plumbing projects on their own. It’s an entirely different style of growing than soil-based methods.
Equipment for Automatic Watering
There is some basic equipment you need for an automatic watering system. Essentially, you need a place to hold the water, a way to push the water where you want it when you want it, tubes to get it there, and potentially some diagnostic equipment and fertilizer. Specifically, you need the following:
The pump needs to be able to push water up a hose and away up to ten feet. On average, one pump can cover a maximum of ten plants. On average, assume that your pump should be able to handle 60 gallons per hour, per plant. It should also be submersible.
A large rain barrel is perfect for your cannabis watering system’s reservoir. It should be big enough to hold water for several days, otherwise, you’re just filling the reservoir every day instead of watering the plants.
Your timer helps dictate when the water pump is running. Ideally, choose a 24-hour timer than gives you fine-detail control over when to turn the pump on and off. Some timers only work in intervals of 15 minutes, and that can easily be too long if your plants are still small.
½ Inch Poly Tubing
This is your main feed line. It should run from your water pump, through or over the side of the water reservoir, and past all your plants. Ten or twenty feet should be enough per pump.
This plugs the far end of the poly tubing. It prevents water from escaping at the end, so it all has to leave through the drip emitters.
Scissors should suffice to cut all your tubing.
Clamp and Pierce Connectors
These connect to the poly tubing and pierce a hole in it. The hole should self-seal around the spike. The other end of the spike is where you attach the drip emitters.
¼ Inch PE Tubing
The simplest method of making a drip emitter is taking some PE tubing and poking holes in it with scissors every two inches. You can also get inline drippers, which are small plastic pieces with holes that stake into the soil. You would cut the PE tubing where you want a dripper, and slide tubing onto either end. You can get small end caps or terminal drippers to end the drip emitter line.
This helps you keep an eye on water problems before you send it to your plants.
Freezing-cold water will hurt your plants. Use an aquarium thermometer to make sure it’s about room temperature.
You can add fertilizer from the get-go so you can automatically feed your plants when they’re watered.
If your water is fertilized, an aerator keeps the fertilizer from losing efficacy.
How to Set Up a Drip Emitter System
A drip emitter system is by far the easiest to set up.
First, place your reservoir somewhere near your plants but out of direct light. You don’t want algae growing in it.
Place your water pump in the reservoir. Read its instructions carefully so you know what parts of the pump can be immersed in water. Attach one end of the poly tubing to the pump, run it over the side of the reservoir and past the plants. Cut to the length you want and plug it with the end cap.
Take the clamp and pierce connectors and place them where you want drip emitters to emerge from the main line. One or two per plant is good. Cut the PE tubing to your preferred length and attach one end to the connectors. Run the line around the plant you want. Either poke small holes in the tubing when it reaches the soil, or insert in-line drippers. Clamp or add a terminal dripper to the end.
Plug the timer into the wall and program it to your preferred watering schedule. Plug the water pump into the timer. Add the aerator if you plan to fertilize the water. Fill the reservoir, and you’re done!
Ideally, you want to water every two or three days. This gives your plants some time to dry out without wilting. Your soil should be dry on the top inch or two before you water again. If your soil is drying out quicker than that, water more thoroughly. If your plants never get to dry out, then they can face root rot, and you should water less often or give them less water at a time.
You should only water with full-strength fertilized water every other time. Consider filling your reservoir only halfway and adding fertilizer every other time you fill it. This prevents nutrient burn while still automating your watering schedule.
You’ll spend the first few weeks of your automatic watering system fine-tuning it. During that time, watch out for signs of over-watering or under-watering.
Under-watering makes plants wilt. The leaves will look limp and droopy, and the whole plant may start to lean. Eventually, leaves will start to become dry and crunchy. The soil will be dry to the touch, and pots will be very light.
Over-watering can also make plants wilt, unfortunately. However, over-watered plants will never become crunchy. Instead, they will turn brown or yellow and limp. The biggest sign that a plant is overwatered is that it’s wilting but the soil is wet to the touch. Let the plant dry out and reduce the frequency or amount of watering when you start again.
Automating your watering system can take a load off your shoulders. Automatic systems let you go away for a few days without worrying that your plants will die in the meantime. They can also help you increase the number of plants you can handle. Automatic systems aren’t necessary, but they’re helpful for everyone from beginners to long-time growers.