Away For Weeks-- Advice on Automatic Watering and pH (Suggestions/Question)

Discussion in 'Advanced Marijuana Cultivation' started by Majikoopa, Sep 8, 2017.


    Majikoopa Well-Known Member

    Hi All!

    So for years I've been looking into the right system to keep plants watered when away on a trip. I've found that you can really over water plants before leaving and give a couple extra days of moisture by filling the saucer up, but clearly that's not the healthiest advice. I finally found a method on what works, so I'll list it below but I've got a question too.

    Here's the setup: Get a reservoir (I use an 11 gallon black bucket) and a pump. Get yourself a timer that can be programmed down to the seconds. I set mine for about 30 seconds. Get some tubing and some drip system stakes and attach these to your plants. My soil tends to be a little loose so I will also use some cheap clamps and clamp the line to the edge of the pot without bending it. Here's a key I found-- you (obviously) need to measure how much water gets added to your plants and adjust the timer accordingly, but even if you do that you may get a siphon affect... weirdly, the bottom of my siphon was lower than the exit holes, so not sure why I got that, but it would siphon for a while before dying down... just put a little pinhole at the top of your line and this will interrupt your siphon because air will get in the line... this does not affect the pump outside of a few squirts. For that reason, my pinhole is inside of my water reservoir (which has a lid).

    ANYWAY-- this system works really great and I was able to take a two week vacation DURING flower with dry nutrients in the soil, slowly releasing with no ill effects. Even after coming back, I let it coast for another 10 days before finally starting to hand-water again... why?

    I had a problem. My plants started having a nutrient lock-out even though the soil was adequately amended. Apparently, over time, the PH of the water in the reservoir started raising on its own. It started out at about a 6.0, but by the time I measured it it became about a 7.5. The plastic of the reservoir isn't supposed to be reactive, so is this just from sitting around? Has anybody had water slowly raise its pH seemingly for no reason?

    Any advice on why this is happening and how to keep the pH steady over time? Is there a buffer I should add?

    ANC Well-Known Member

    Water from the tap has an artificially low pH due to CO2 under pressure in the pipes.
    As it gasses off pH starts to rise. Then when you add it to your plants it may absorb bits of decaying organic matter which gives off ammonia as it breaks down further increasing pH
    Majikoopa likes this.

    Majikoopa Well-Known Member

    That makes a lot of sense! Wow, ok so maybe let the H2O set for a while to gas off THEN adjust the ph before I take off. Thanks!

    ANC Well-Known Member

    It is still going to rise a bit, but it is better to start off at the correct point. Remember the roots also exudes lots of stuff back out while drinking your water.
    Majikoopa likes this.

    Majikoopa Well-Known Member

    Thanks man big help!
    Lucky Luke

    Lucky Luke Well-Known Member

    Large SIP

    nachooo Well-Known Member

    I have got this problem when I used some autopots, After some days the ph raised... my tap water has a high ph and even after correct it, it raised over time, I read somewhere that this can happen and a way to avoid it , was using an aquarium air pump inside the water tank... the problem was that the plants were in my bedroom (yes, I slept with amy girlfriends all together) and the noise was disturbing..but also I have read that instead of and air pump you can put inside the tank an aquarium water pump, moving the water constantly and you can get the same effect with much less sound than with an air pump.. It worked for me. Hope that help you

    SomeoneWhoIsn'tMe1115 New Member

    I have done this before also, but with two reservoirs instead of one. One had liquid nutes (shame on me). Both had aquarium pumps circulating AND aerating the water (think waterfalls).

    It is hard to find a timer that supports both day of the week programming (to schedule nutes), and one second precision. My solution? Plug a timer into a timer! Synchronize them so they work together. Put the second timer on a loop (2 minutes 15 seconds on, 2 minutes 45 seconds off, totaling 5 mins). Schedule the minute timer to kick on at a time divisible by 5 minutes so it thinks it's running for 5 minutes at this time but really it's running for 2:15.

    $30 for 4 timers and you're all set to schedule nutes twice per week or whatever you do with precision control.

    You can really fine tweak the water dosage by adding a flow control nozzle onto the outlet stream (just don't touch it once you've set it unless you plan to change and monitor, time is much better to adjust because it is linear so you can calculate new water output). I then diffuse it across about 6 water drip nozzles around the pot(s). I haven't done this with more than one plant. I think I would add additional pumps and timers to allow me to fine tweak each plant.

    Typical run time for me is more like 2-3 minutes which I found gave greater repeatability after adding the flow adjustment.

    As fart as the siphoning effect goes, I use the suction cup mounted submersible pumps so the pickup tube will always be lower than the outlet drip nozzles; making it impossible.

    This is my preferred watering method even when I'm not away. It find I can really get the plants to thrive this way. Once you have it laid out and safe you can go a few days without thinking about your plant. Ahhhhhh (sigh of relief).

    ruwtz Well-Known Member

    Are you recirculating? Sorry I couldn't see in your post but if so you would be correct to see a gradual rise in pH anyways as salts are removed from solution by the plants. All part of the greater concept of soil acidification and is a handy indicator that plants are healthy and feeding.

    On the topic of automating the garden, I can get 6 days out of my timers and pumps before reservoirs run dry. But more crucially than that there's ample other jobs in the same timeframe that just can't be avoided or automated. Things like training, lollipopping, canopy management etc are every day jobs over here.

    I recall seeing some pretty amazing DIY designs for self-regulating reservoirs with injectable nutrients and pH solutions all on programmable controllers. I was impressed but nowhere near inspired enough to do it :clap:
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