Time for a Change?
Even the keenest of hydroponics gardeners is unlikely to be able to be on-site and tending their garden 24/7 (i.e. all day, every day). However, part of the art of successful growing is down to certain events in the grow-room happening at the correct times. For example, lights and/or heaters need to be turned on and off at the right times. Another example is that for hydroponics systems, waterings need to occur regularly and reliably.
Because these events need to happen even when the gardener is not there, it usually becomes necessary to automate the switching process with a time switch. There are several different types. In this article we’ll take a look at what’s available.
The most common type of time switch is the standard 24Hr mechanical plug-in type (sometimes called an analogue or segmental timer) such as the ones made by Optimum or LUMii. These types of time switch plug directly into a mains outlet socket and the equipment to be switched on and off is plugged into the front face on the timer. A rotary 24 hour clock (also on the front) is set to the correct time and the desired on-times are set by the position of segments around the outside of the clock face. Each segment typically represents and controls an on or off time of 15 minutes.
To set an on-time, the appropriate segment(s) is/are clicked over towards the outside of the face (the outer position). Segments representing times that you want the equipment to remain off are set to the inner position. As many segments (on-times) can be set as desired, and for longer on-times than 15 minutes, several adjacent segments can be set to the outer position as necessary. Once set up, the timer will switch pumps etc. on and off at the same times every day. Usually, a manual override switch is provided so that the user can select between the output being always off, timed, or always on:
For a long time, the firm favourite of growers everywhere was the Grasslin standard analogue segmental time switch. The Grasslin was super-reliable, in fact no one at One Stop Grow Shop can remember one ever being returned to us as faulty! Although Grasslin have stopped manufacturing their timers, the same bullet-proof reliability is still available from the Optimum OP-TIP1000 Plug-in Time Switch which is designed and made to Grasslin’s specification. Only the outside cosmetics, the name, and the place of manufacture have changed.
Most standard time switches of this type are not designed for switching high power equipment on and off, particularly if they draw a large inrush current at switch-on. They are fine for switching most items such as CFLs, water pumps and fans on and off but any item that draws a large instantaneous current at switch-on, such as HID lights (HPS, MH CDM etc.), will quickly destroy the contacts of the switch, most often welding them together, making it impossible to turn the power back off again.
For switching HID lights on and off, the timer needs to be assisted by the addition of a relay or contactor switch (such as the Smart Gro). In this configuration, the timer tells the contactor to switch power to the ballast. The actual power for the ballast is sourced from a different socket to the one that the timer is plugged in to.
For those just starting out or who on a very tight budget, Lumii make a Heavy Duty segmental timer which can handle switching one 600 Watt HID grow light. While this timer is great value for money and will serve its purpose well, we would always recommend upgrading to a higher quality HID light switching system (like above) as soon as funds allow.
There are many multi-outlet contactor boxes, such as the GreenPower brand, that conveniently contain an integral timer (most often a Grasslin) so that you don’t have get one separately. They are available with different numbers of outlet sockets and power ratings:
Program Your Grow for the Whole Week
There are growers out there that like to grow their plants in soil but also like to have an automated watering system such as with a Wilma dripper system. Soil retains large amounts water and it is fairly rare that plants in soil need watering every day (except, possibly, large plants at the peak of flowering or when they are grown in small pots). If a standard 24Hr segmental time switch is used to switch on the watering pump, then timed feeds will occur every day which is very likely to lead to overwatering, with the accompanying problems that comes with it. For soil-grown plants, it is wise advice to allow the soil to dry a little in-between waterings. This means that waterings may only be required 2 or 3 times a week. In this particular application, a 7 day digital time switch might be the answer. One of these could be programmed to power the pump to water the plants, say, for 10 minutes on a Monday and again for 10 minutes on a Thursday.
Time Switches Go High Tech!
A recent innovation by Optimum (the makers of time switches for Grasslin) is a digital time switch with a wi-fi facility called the Optimum Connect. It can connect to your wi-fi router at home and then the time switch can be monitored and programmed anywhere via an app on a smartphone. Just like other electronic programmable time switches, the Optimum Connect can be switched on for just 1 minute or for as many minutes as you like. As many of these time switches can be controlled by the app as you like. The limiting factor on how many you can use will usually depend on how many devices that your router can connect to (often about 15). State-of-the-art encryption ensures against wi-fi security issues. Imagine the possibilities! With a bit of creative thinking, almost your whole grow can be controlled from wherever you are in the world. However, remember, each of your computers, tablets and smartphones which are connected to your wi-fi router will take up one of those connections, reducing the number of these time-switches that can be controlled through it. The Optimum Connect features an on-off manual override switch on the front, and it can switch a 13 amp resistive load or a 2 amp inductive load which is similar to the analogue segmental type time switches.
…..and here’s the app on a smartphone:
Take Even Greater Control!
In some situations, 15 minutes is too long a period for equipment to be on for. IWS have catered for growers who want greater precision over dripper feeding times with the IWS second/minute timer. On-periods can be set by a control in either seconds or minutes. Each time that an on-time is triggered by the integral Grasslin segmental timer, it switches equipment on for however many minutes or seconds that have been set by the user. Instead of the segments on the Grasslin timer directly controlling the output (which would mean 15-minute on-periods), the Grasslin timer is simply used to trigger an on-period, the length of which depends on what has been set on the second/minute control:
These particular timers are designed to allow precise length on-periods down to as short as one second or up to as long as 15 minutes. This means that a watering cycle can be set to last for only as long as absolutely necessary. This reduces the chances of overwatering down to an absolute minimum. The switching on of the second/minute timing section depends on the built-in Grasslin timer moving from a segment which is in the off-position to a segment which is in the on (outer) position. It’s that change which triggers the the on-period (which then lasts for as long as is set on the minute-second knob). Afterwards, the timer must then go past a segment in the off position before another on-period can be triggered.
Also in the IWS product range is the Remote Timer which connects directly to the brain pot. It has a specialist connection just for this purpose. The Remote Timer allows the user to set a time for the flood/drain cycle via the integral Optimum (Grasslin) timer. The user can then set an on-time length for the feed pump via the knob on the front face. With a press of the knob, the user can then set an on-time for the Drain Pump.
In a similar way to the Dripper Timer, the Optimum Time Switch must go through an off-period before another Flood/Drain Cycle can be activated again. This unit is an upgrade “bolt-on” for those who want maximum control over their Flood/Drain cycle times.
In conclusion, there is a time-switch solution for virtually any purpose that a grower will encounter. We stock them all at One Stop Grow Shop!