When you are going away for a few days only, your garden plants will probably be just fine, providing you treat them to a good soaking just before you go. Ideally, your garden ought to be mulched. It will minimise any loss of water through evaporation. Two the three inches of mulch will suffice. Any more, and you run the risk of stopping the supply of oxygen to the plants' root systems.
Once you've completed the soaking, get a shovel or a longish screwdriver and poke down through the soil a few inches below the surface. If it's wet down there, your garden plants should survive if they're left for a few days.
Watering via a Rain Barrel and Soaker Hoses
If you will be away from your garden for a longer period, soaking and mulching may not be sufficient. But if you've got a decent rain barrel and some soaker hose, you can try the trick I am about to share.
Make sure that your rain barrel has a decent amount of water in it. If you then attached the soaker hose to the bottom of the barrel, gravity will push the water through the hose and thus soak gently into the ground on which it is laid. It will still be necessary to give your plants a good soaking before D Day, and if you do, the water butt trick is a nice simple solution to keep your plants watered for a longer absence.
Just make sure there is sufficient rainwater in the barrel. If there isn't enough, you can always top the level up with tap water. Needs must when the devil drives.
Using Recycled Plastic Bottles
If you don't own a rain barrel, an alternative solution is to use recycled plastic bottles. Remove the caps from however many empty bottles you are using, and poke a small hole in each of them using a nail, a bradawl or a sharp-pointed knife. Another option is to use plant watering spikes.
As with the rain barrel procedure, give your plants good soaking before your departure date. Just before you go, screw the tops back onto the bottles or use irrigation spikes, turn the bottles upside down and push them into the soil next to the plants.
A course, you will probably require a number of recycled plastic bottles in order to keep all of your plants watered. However, on the positive side, this homemade system is easy and cheap to organise and once deployed, the water will be slowly dripped into the soil, keeping your plants watered.
Ordinarily, one-litre bottles should be ample for two weeks but use two-litre bottles instead if you will be away for longer. Bigger bottles will, of course, be somewhat heavier, so you need to make sure they are stable and won't tip over.
Install a Drip Irrigation System
If you want to be a little more professional about keeping your garden plants watered while you're away, and especially if being away is a frequent occurrence, the best solution is to install a drip irrigation system.
Installing a drip irrigation system might sound rather difficult, but in actual fact, it is quite a simple procedure. You will be able to purchase inexpensive kits that essentially just click together from your local DIY store. If you do decide to go down this route, it is best to carry out the installation at the beginning of the growing season.
You'll find it much more difficult to deploy the hoses once the garden plants have grown large, so you need to plan ahead. If, however, you have left it to the last minute, it's still not impossible to do, but it will involve a little more hassle.
A drip irrigation system targets the roots of the plants, thus helping to conserve water. It's a good idea to install a timer on your spigot. Not only does it mean that you won't have to worry about when to water your garden, but if you're going to be away for a while, the watering will just take place automatically.
You can even buy more sophisticated timers that can sense how much rain has fallen and adjust the watering cycle accordingly.
Watering Your Lawn
If you're only going to be away for a week, your lawn won't even miss you. Also, during the heat of summer (if that is when you're going away), lawns grow more slowly, so all you will need to do before you go is to cut it to its regular height and give it a deep watering before you leave.
Water Timers and Irrigation Controllers
If you plan to go away for longer, and this sort of absence is likely to be repeated, you could think about installing a mains irrigation controller. These sophisticated devices provide multiple connection options that allow you to control several zones to keep you in control of your home irrigation requirements.
They have inbuilt timers and programmers, so you can adjust the settings as required. They are suitable for both indoor and outdoor installation.
If you are serious about gardening and the best way of constructing an irrigation system to operate both when you are at home, and while you are away, water timers and irrigation controllers are the way to go.