Watering Container Plants

Container gardening is the mainstay of apartment and small-home gardeners. But even with four acres to play on, we plant plenty of succulents, herbs, vegetables and a few ornamentas in containers. For gardeners with more space, containers add convenience for kitchen garden edibles, and for moving plants that spend winter indoors. There are plenty of reasons to choose containers and plenty of ways to manage water use with container-grown plants.

nasturtiums rustic container
Why not repurpose an old washtub when you’ve got nasturtium seeds begging for a sunny spot?

The right plant

Annuals are great choices for container gardening, since you don’t ever have to repot the plant. And since xeric perennials need little water once established, having some annuals in containers or a small bed is a perfect splurge, especially if the annuals reseed.

It’s true that container plants need more frequent watering, so low-water herbs and other xeric plants make the best choices. But you can grow edibles and any small plant in a container. In my mind, the water for edibles produces food. And as long as I water responsibly, I’m OK with using a container and hand watering lettuce and tomatoes instead of using drip irrigation in the ground.

chile pepper in metal container
This green chile didn’t do well in such a small container, but it was fun to place on the patio. And we got a few peppers from it.

When creating arrangements, place plants with similar sun and water needs together. If you really want a centerpiece plant that uses a little more water, find a way to contain it by placing it in a plastic nursery pot (probably a few inches larger than the one it came in) inside a larger decorative one. Underplanting with flowers can disguise the trick that lets you focus a little extra water on one plant without overwatering others.

Selecting containers

I love to repurpose and use fun and funky containers when I can, but I typically use well-designed plastic or glazed containers for edibles. Plastic containers usually use the least amount of water, and glazed containers slightly more. We have lots of clay containers too, but we reserve most of those for cacti and succulents. Clay dries out quickly, so it’s best reserved for the lowest water users. And although photos always show containers filled to the edges with plants, consider mature growth even for summer annuals. For example, petunias multiply! It’s so fun to create a mini-garden scene with a big grouping of containers, especially if you have the space and money. I have a small grouping of more attractive and slightly lush containers in the front of our home, but the ones in the back are for function as much as form.

Cacti and succulents do well in clay pots and most containers.
Cacti and succulents do well in clay pots and most containers.

Prep the container

It’s important to use good soil for container plants and not extra dirt from the hole you just dug for your rose bush! Placing it in a pot just creates a big, clay petri dish for disease, insects and weeds to grow in. Soil also tends to compact more easily in a container. And the nutrients available for flower and fruit production are limited compared with the big, open ground.

Japanese maple in container
I love the combination of Japanese maple, bamboo and the container.

You can add small stones along the bottom to help with drainage and reduce watering by using a potting mix with polymer crystals that hold some moisture and then release it. Or add something more sustainable such as Growstones. Just don’t use a rich mix that retains moisture for cacti or other plants that need well-drained soil.

carrots growing in trough
It takes a lot of soil to fill a trough. Look for local compost and garden soil bulk suppliers.

When choosing organic potting mixes for edibles or just because, use some caution. Many potting mixes labeled organic are so similar to compost that they contain plenty of nutrients, but are too dense to use alone. A lighter mix helps air and water reach roots. Look for organic fillers such as coco husks. And don’t overfill the pot; you need a few inches at the top for water to sit while it drains down. If you get the soil level too high, water can run out the top of the container.

Water slowly

The key to healthy container plants and water savings is to water slowly. Flooding a container plant washes out important soil nutrients. Placing a small coffee filter over the drainage hole allows water through but stops soil and  nutrients from washing out the bottom. I try to pour slowly from my pail and then return a few minutes later for a second slow watering as I make my way from container to container. We use rain water as much as possible for container watering.

If you have a drip system with good pressure, you can have it set up to water containers, especially grouped one. You could use an olla, which is a clay bottle you bury in the container that slowly seeps water and can be refilled. To me, one of the best qualities of containers is that you can move them to meet shifting sun requirements or whims. And when a plant begins to wilt, it might not need more water – it just may need less sun.

Healthy looking native plants outside the Native Seeds/Search store in Tucson, Ariz.
Healthy looking native plants outside the Native Seeds/Search store in Tucson, Ariz.

I’m not big on fertilizing because it can lead to too much leaf and branch growth (and not enough to fruit and flowers) or burn plants if done too soon or incorrectly. I’d rather keep improving soil in beds so plants get most of their nutrition each year from natural ingredients. But container plants can need a little extra help. Compost tea or a light application of a product like Happy Frog every few weeks can support container plants.

I’m hoping to order some new containers this year locally or from Arizona Pottery. I’ll update when I can.