- What is needed to automate irrigation
- Drip irrigation
- Subsoil watering
- Ways to control automatic irrigation
- Control panel, programmer
- GSM module
Scheduled irrigation system in the greenhouse can be assembled independently like a constructor. In this material, we will consider in detail how to make automatic irrigation in a greenhouse, and what equipment is required, taking into account the peculiarities of drip, subsurface irrigation or sprinkling.
For the normal growth of plants in a greenhouse, watering plays a key role, because there are simply no other sources of water. In order not to run constantly and not waste time manually irrigating the beds, it is easier and more convenient to assemble automatic watering, especially since all the components for this in a huge assortment can be found in a construction hypermarket, hardware store or an online store specializing in garden equipment. To determine the required set of components, the features of irrigation automation depending on the type of irrigation and the degree of automation are described below..
What is needed to automate irrigation
To completely exclude from your schedule the daily watering of the greenhouse and at the same time provide the plants with ideal conditions for growth, you need:
- Install a distributed nozzle system for sprinkler, drip or subsoil irrigation.
- Instead of conventional valves and shut-off valves, install solenoid valves or supplement the valves with servo drives. Install power relays to control the pump.
- Choose the optimal control method: by timer, using a programmable control unit, by a signal from a mobile phone.
As a result, you will get an irrigation system, which is enough to set up once and only from time to time check its performance.
Scheme of automatic irrigation in the greenhouse. 1. Well. 2. Pumping station. 3. Ball valve. 4. Valve with servo drive. 5. Control unit with GSM-module. 6. Air / soil moisture sensor. 7. Greenhouse
It is imperative to include coarse and fine filters in the circuit during assembly in order to protect valves, shut-off valves and nozzles from contamination and premature breakdown..
Each plant in the greenhouse is watered by gradually irrigating the soil directly near the trunk. Drip irrigation is a low-pressure system. To maintain the required pressure in pipes and hoses, a storage tank is used, raised above ground level, a reducer or a pump that does not exceed a predetermined pressure threshold.
To automate irrigation, it is enough to use a solenoid valve connected to a programmable control unit, or a valve with a timer for each irrigation zone. For the storage tank, unconditional filling must be ensured using a level sensor or a float valve.
It is important that valves, especially those combined with a timer, maintain zero water pressure as the target pressure in a drip system rarely reaches more than 3-4 bar.
It is necessary to automate a pressure irrigation system with a distributed grid of nozzles. To irrigate the entire greenhouse at the same time, it is enough to turn on and off the water supply to the nozzles. There are two options:
- Well with a submersible pump. It is enough to use a power relay to turn on the pump on schedule. The pump power must be sufficient to operate all involved injectors.
- Pumping station or access to a centralized water supply, the pressure in the system is constantly maintained. Watering requires a solenoid valve to turn on the water supply.
Several crops can be grown in the greenhouse at the same time, for which you should select your own irrigation regime, different from others. Several controlled valves are required for each nozzle group. A similar conclusion for greenhouses of a large area, in which simultaneous watering is impossible, since the pressure generated by the pump will not be enough for the operation of all nozzles at the same time.
In greenhouses, fogging systems are often used instead of traditional sprinkling, which can maintain the required level of air humidity and soil water saturation.
Sprinkling involves intensive irrigation with a large volume of water, so a single irrigation time is only 1-15 minutes. To control the valves, it is better to use a control unit or a timer with the ability to set the start of irrigation depending on the time of day and day of the week..
This type of irrigation is based on a gravity water supply, as in the case of drip irrigation, only the pipes are buried to a certain level, imitating the top water (groundwater) in a greenhouse. Unlike drip irrigation, this scheme does not imply interruptions in operation, so automation is theoretically reduced only to installing a level sensor in a tank with a water supply.
However, in reality, intra-soil irrigation gives positive results only if the optimum soil moisture is maintained, which depends on the activity of plants and a number of external factors. To automate this irrigation scheme, you need to regulate the water supply depending on the readings of the humidity sensor. It is advisable to use adjustable solenoid valves with the ability to change the volume of incoming water.
Ways to control automatic irrigation
The degree of automation of irrigation in the greenhouse directly depends on the functionality of the control unit. It was previously indicated that control can be carried out by a timer or a control panel. You can also add GSM-modules and a smart home system to them. It remains to choose the best option.
Complete automation can now be provided by controllers assembled according to an individual project based on programmable Arduino modules
Both mechanical and electrical timers can be used, which are capable of controlling the valve according to the set time delays. Watering timers are combined with a valve controlled. Most often they run on two AA AA batteries, which are enough for about 1000 on and off cycles. Installed in a burst of the supply pipeline.
Simple timer models are designed to set only two parameters:
- Watering time (intensity). More often regulated from a few minutes to 3-4 hours.
- Time interval between waterings. Standard range 1-48 hours.
This is quite enough for the organization of drip irrigation, in which it is enough to determine the frequency of irrigation. However, for different stages of plant growth in the greenhouse, adjustments will have to be made..
Each zone in the greenhouse has its own water supply line, on which a servo-driven valve is installed, controlled by a separate timer
The programmable timers are also designed to control a single irrigation zone, but you can have several different programs that are stored in the device’s non-volatile memory. You can set several types of watering at different intervals, link watering to the time of day or days of the week, create a detailed schedule.
Important characteristics when choosing a timer:
- minimum allowable pressure (models with a zero lower limit are perfect for low-pressure drip irrigation);
- maximum allowable pressure (4–6 bar);
- the throughput of the valve, which determines the number of possible nozzle connections in one irrigation zone.
Control panel, programmer
Irrigation Programmable Control Units are designed for:
- work with one or more irrigation zones simultaneously (determined by the number of outputs for connecting solenoid valves);
- setting the frequency of watering for each zone separately;
- setting the irrigation intensity.
In addition, it should be clarified whether the selected control unit has functions such as:
- preset irrigation programs or the ability to set your own modes;
- limits for setting the frequency of watering and intensity;
- the ability to connect external sensors for conditional and unconditional execution and selection of programs (connection of a humidity, rain sensor, etc.).
When choosing a model, it is important to match the electrical parameters of the output signals and the requirements for the control input used by electromagnetic relays so as not to exceed the permissible current.
To control power loads, such as pumps or servo drives, it is necessary to select electromagnetic relays that will switch the power supply of these devices. Key parameters are: control signal format (volts, milliamps), permissible switching current (amperes).
In a wide range of products on the market, there are GSM modules for controlling electronic equipment in the house using commands transmitted from a cell phone. They can also be used to organize greenhouse irrigation. Only modules for which you can set time-bound programs will help to fully automate the process, otherwise you will have to turn on or off irrigation by sending an SMS message every time. Alternatively, it is enough to connect the GSM-module to the irrigation control unit that supports external commands.
GSM-modules allow you to fully control and automate the process of watering the greenhouse