Gutter gardens (or ‘rain gutter gardens’) are a simple way to deliver water to your plants with so little ongoing maintenance after they are established that you may as well go on holidays.
As the name suggests, the key component is a piece of gutter such as you use to catch the rainwater from your roof. You add the ends to make it water tight, then support it with a frame, The frame is not necessary in all cases but, with many gutters being made of plastic nowadays and the heat increasing, it is probably a good idea to have one.
The gutter is where your water and nutrients are added,
Your plants are held in plastic buckets with a simple modification. The bucket has a hole in the bottom into which some kind of cup with holes in it is positioned. I’ve used net pots, 5 cm garden pots with a couple of extra holes and even plastic party cups (recycled, of course) with holes in them.
The cup and bucket are filled with potting mix filled and your plant is planted into them as you would normally plant it into a pot.
I’ve found that a good precaution against letting the water level get too low is to place the bucket and cup onto the gutter when it is empty and dry and mark on the side of the gutter a point 1 cm above the bottom of the cup. This will indicate when to fill the gutter again and ensure that the cup is never out of the water.
Fill the gutter with water and place the bucket over it with the cup at the bottom extending down into it. The potting mix will absorb the water and it will rise into the bucket through capillary action, delivering it to the roots of the plant.
You can add soluble such as seaweed liquid or even hydroponics fertilizers. nutrients to the gutter so that it is ready for uptake by the plants. I’ve found that a little soluble fertilizer granules with extra trace elements added to the potting mix helps enormously.
Top up the water whenever it is getting a bit low. If a cup isn’t in the water, it can’t take up water and nutrients and the bucket will dry out. You can top up by hand or some folks fit a float valve to the gutter and connect it to a rain tank or to the mains.
If you’re really clever you can join multiple gutters together with siphons (I’m dedicating a whole page to siphons soon). Many folks mount the gutters vertically, with the overflow from the top being the source of water from the next one down. This system needs a strong frame as water and wet potting mix can be quite heavy (remember 1 litre of water weighs 1 kg).