Watering Plants on Hot Summer Days
Make a Plant Water Reservoir
If I'm going on holiday or temperatures are soaring, I have a quick trick that will help you keep your patio and deck plants hydrated.
Fill a two-liter bottle with water and place a small piece of sponge in the neck. Upend the bottle and bury the neck into your pot's soil as close to the plant stem as possible. Use an inexpensive sponge, and cut pieces just slightly larger than the bottle opening.
The sponge will help dispense the water slowly over the course of a few hours, keeping your plant wet enough to stay cool, moist and comfortable.
Special notes: Place the sponge far enough inside the neck of the bottle to stay put but not so far that it passes through the narrow neck into the wide end of the bottle.
Don't wad or compress the sponge too much or the flow of water will be too restricted. (This may take a little experimentation.) I cut small sponge "squares". Pushing the slightly larger corners into the bottle's neck provides enough pressure to keep the sponge in place, but the sponge is still porous enough for the water to flow at an even drip.
If you plan on doing this for a number of days, cut the bottom off the bottle. You can do this with a pair of scissors after making a small cut in the plastic with a sharp knife. Once the bottom (the top once the bottle's in place) is gone, it'll be easy to add water from your hose or watering can allowing you to leave the bottle in place for days or even weeks at a time.
Check the water level to make sure you have a flow rate the works for your plant. If it's too fast or slow, make adjustments in the density of your sponge.