Filling planters with beautiful flowers, herbs and edibles is an easy and affordable way to add color, fragrance and food to unused spaces. The downside, of course, is that more containers mean more watering. That’s because potted plants are more prone to drying out than those planted in the ground. But adding reservoirs to your containers is a great way to help keep your plants from getting too thirsty – even in warm, dry weather.

Drainage kit

Easily installed, this water-reservoir kit keeps plants from growing too thirsty (as long you remember to fill it).

Photo Credit: Mary Moore

Do-it-yourself water reservoir - step 1

Step 1: You can also install a do-it-yourself water reservoir with just a deep plastic dish, some gravel and landscape fabric. After placing a deep dish into your planter, fill it loosely with stones, and cover any gaps around the dish with extra gravel.

Photo Credit: Mary Moore

Do-it-yourself water reservoir - step 2

Step 2: Cover the stones with a single layer of landscape fabric. This keeps the soil from falling into the water.

Photo Credit: Mary Moore

Finished do-it-yourself water reservoir

Plant your container as you normally would on top of the liner. The reservoir will hold extra water and keep your plants from getting too stressed.

Photo Credit: Mary Moore

You can add a reservoir to a planter in two ways: You can add a tank or absorbent liner to the inside of the container, or your can place the planter in a deep dish and allow the water to collect outside of the pot.

There are several advantages to adding a reservoir inside your planter: It doesn’t detract from the attractiveness of your display, and it’s easier for the roots to reach the water inside the planter when the soil is dry. (Of course, it’s important that the container you place the reservoir in has at least one drainage hole in the bottom to allow extra water to run out.)

Ready-made kits are available to ease the installation process. It should contain a tank, a drain to separate the tank from the soil, and it should have the ability to overflow and drain extra water out. It’s also nice to have a pipe from the surface so you can add water directly to the tank when needed, as well as a “dip stick” to test the water level. (When installing the kit, check to see if the tank fits too tightly that the excess water can’t drain out through the hole in the bottom of the planter. If necessary, put a few stones under the tank to allow space for drainage.)

Another option is to use a drainage mat that absorbs several times its weight in water and then releases it gradually to the plant as needed. These mats can be purchased through seed companies and are often sold at garden centers in spring. (These are great options for hanging baskets because they hold water without taking up precious space.)

And, of course, you can always build an internal reservoir from scratch – and chances are you already have the materials at home. You’ll simply need a plastic bowl that’s about 5 inches deep and at least 1 inch smaller in diameter than the planter. You’ll also need enough gravel to fill the plastic bowl, with some extra to put under it and along the sides if necessary, as well as a square sheet of landscape fabric large enough to cover the bowl and run slightly up the sides of your planter.

Just place some stones at the bottom of your planter to create space for drainage. Next, put the plastic bowl on top of the stones and fill it with the rocks. If there’s a significant amount of space on sides of bowl, add some stones in that open space to keep the dirt from caving into it.

Cover the bowl with the layer of landscape fabric, allowing the edges of the fabric to go up the sides. Fill the planter halfway with a potting soil recommended for the plants you’re growing. Add your plants as you normally would, starting with the larger ones. Then fill in the rest of the space with potting soil. Allow at least 2 inches of space between the top of the soil and the rim of the planter. As the plants grow, their roots will grow down into the landscape fabric where they’ll start tapping into the water as the soil starts drying out.

Of course, some containers are too small for a reservoir on the inside, so consider using a deep dish on the outside of your container plant. A heavy-duty plastic dish works very well, but you can also use those lightweight, clear plastic dishes for under houseplants. Place at least 1 inch of gravel in the dish, and make sure that the surface is reasonably level. Put the planter on the gravel, then move the pot around a bit until it’s secure in the dish. Plant the container as usual.

If you find your plants are getting too much water, add more gravel to the dish to keep the pot from constantly sitting in water. (And if your planter is outside, remember to drain the water from the dish after a big rain.)

With just a few inexpensive and easy-to-acquire items, you can prevent stressing your plants by making sure they’re well-watered – even when you’re not there. The end reward for the extra work is a little break in watering and all the beautiful contained flowers, herbs and veggies you’ve dreamed of!