Really Easy Automatic Plant Waterer

Electronic watering systems are great for greenhouses but can be expensive and break easily. For outdoor vegetable patches, this is the best, easiest - and cheapest - way that I've found of watering plants automatically.

What you'll need:

• Empty plastic bottle - with its cap
• Something pointy - e.g. scissors, cross-headed screwdriver or an awl
• Small stones (optional)
• Soil
• Water
• Trowel
• Gloves (optional)
• Watering can/hose (optional)

If your bottle of choice has a label on the outside, it's worth peeling it off now. (If you leave it on, it might fall off in your garden and only reappear when you dig up your potatoes...) It's also a good idea to wash the bottle out at this stage. Milk and fruit juice tend to get particularly smelly if left outside for a long time.

This is where the pointy stuff comes in. From experience, I'd say that an awl is the easiest tool to use but scissors or screwdrivers can work too.

Hold the bottle upside down and pierce 3-4 small holes in the base. (If it's too hard for this, you could make the holes in the side instead. Just keep them really close to the bottom or lots of water will never run out of the bottle.)

At this point, you might need to do some experimentation. The more soil and stones you put in, the less water will fit in the bottle. However, it would reduce the speed at which water flows from the holes, making it last longer. As a guide, I'd usually fill the bottle to about 1/5 with stones and soil.

If I'm leaving the plants unattended for longer, I'd place bottles with more and less soil alternately along the veggie patch to make sure everything will remain well watered for longer.

The stones also help to keep the bottle upright but they aren't essential.

I highly recommend doing this before filling the bottle with water, if you have a hose or watering can. (If you need to use a tap to fill the bottles, you don't have much choice, but carrying filled bottles can make a mess.)

Try to dig a hole that's just the right size for your bottle's diameter and about 1/3 the depth of your bottle. Place the bottle upright in the hole and refill any gaps around the sides with soil, patting it down with your trowel or gloves.

An extra piece of advice is to make sure there aren't big gaps around the base of your bottle where the holes are. Otherwise, water might flow out into those gaps really quickly, emptying your bottle in a few hours rather than days.

This is where having a hose or watering can to hand can help a lot. Once your bottle is securely planted, fill it to the top with water and screw the cap back on. You'll notice that water will run out pretty quickly with the cap off - because air replaces the missing water straight away - but it flows much more slowly once the cap's back on.

And with that, your plant waterer is complete!

Depending on the bottle size, number of holes and amount of soil used, the bottle will be able to keep your plants hydrated for anywhere between 3 and 15 days so it's well worth testing this and adjusting the bottles before you go away.

If they empty too quickly, add more soil. If no water comes out at all, either leave the cap off or pour out some of the soil. If you have any other problems, let me know in the comments and I'll see if I can help!