Smart Home Irrigation

ginger plant

Combined with rain water harvesting smart irrigation systems can save you considerable effort and money, especially if you are on a water meter. In our dry part of the UK (Suffolk, East Anglia), it can be the difference between keeping expensive plants alive or not. Smart irrigation systems are particularly useful when you go away on holiday.

Smart irrigation systems also allow you to grow more exotic plants and produce plants for food more effectively, such as the edible ginger pictured here.

Passive Irrigation

Before with talk about the smart home benefits and associated technology, it is worth mentioning 'passive irrigation' systems, because these will work for many people. Passive irrigation systems use a water store (often hidden within a plant pot) or a 'drip feed' of water to plants from a separate storage tank. These can be hugely increase the time plants can be left unattended.

Context

A smart home irrigation system is going to work much more effectively and efficiently if it also has context and knowledge of the environment it is operating within. This is why we have ensured our contextual smart home has all of the information and data required, such as a rain sensor, weather forecasts, etc.

Gravity v Pumps

If your water storage is above the plant level, you can use gravity to deliver the water. The downside of this approach is that you need a valve to stop the flow of water and if it leaks or fails, the tank will be emptied. The alternative is to have the water storage tank below the plants (e.g. under ground) and to pump water up to the plants. This only requires a pump.

Irrigation Controllers

We have developed a number of irrigation controllers that are slave processors and part of our contextual smart home. Each one can control one or more irrigation 'channels' and each channel can represent an individual plant, a group of plants or an irrigation zone in our garden. We can easily disable each channel if required and each one can also be associated with a soil moisture sensor.

It is our smart home that controls all of our irrigation though and it decides when and where to water plants based on a complete picture of soil moisture levels, water tank levels, current weather and weather forecasts.

Each controller is effectively turning on a pump (and in some cases opening an associated valve), to irrigate a single channel. 12V valves and water pumps are so cheap, that it makes more sense to do it this way. We typically check whether each pump should be run every 4 to 6 hours. Smaller plant pots in a closed conservatory during the summer can dry out very quickly, so we might check more frequently. These are all things that can be easily configured via our smart home though.

Whilst we could operate multiple channels at once, we don't generally do this. We can reduce the peak loads by ensuring that only a single channel operates at any one time.

Water Storage

We use a number of tanks around our home and garden to store water for irrigation. Where ever possible these are out of sight because water tanks are not attractive things to look at and we always aim for a great user experience. The largest storage tank in our garden is hidden underground.

We always monitor water levels in our tanks, to ensure pumps don't run dry. Typically we use float sensors connected to our contextual smart home so that it can notify us of issues but we have also developed a water depth sensor.

Water Distribution

8-port manifold

Most storage tanks have a single outlet and you wouldn't really want to drill multiple holes and add multiple outlets or taps for a multi-channel irrigation system. To get around this issue, we use a manifold with one inlet and multiple outlets. The manifold can then feed multiple pumps (channels), also ensuring that each channel doesn't affect the others in use (e.g. lowers the water pressure or allow air to be sucked in via another channel).

Optimisation

Each channel of our irrigation system(s) can be optimised for each particular type of plant in terms of irrigation patterns and levels. We have some quite exotic plants that light to be kept relatively moist. Other plants like citrus trees need the soil to be allowed to become quite dry before we water them again.

Soil Moisture Levels

It doesn't matter if the irrigation system is being used inside or outside, it makes sense to monitor soil moisture levels. We have developed our own soil moisture level sensor to ensure we do this in an accurate and timely manner. This massively improves the efficiency and reduces water consumption.

soil moisture sensors

We cover these on a separate page.