You probably don’t think about it when you’re giddily planting your containers. But now’s the time you should consider how they’ll weather the heat. We’ve all watched a hanging basket of Wave petunias or a patio pot of lobelia shrivel up on us.
That’s why it’s so important to keep containers consistently moist but not waterlogged. It can be a challenge, but there are lots of strategies for doing this, some more interesting than others.
Take my advice: Forget the disposable diaper idea making the rounds on Facebook. Instead, use these common-sense ideas for making your containers wilt-proof.
The right soil
When you pot up your plants, make sure to use potting soil rather than garden soil or dirt from your yard.
Most commercial potting soil mixes are composed of peat moss, pine bark and perlite — all organic matter especially selected to retain moisture. Some gardeners reuse potting soil for several seasons. If you do so, be aware you’ll need to fertilize each year as the soil loses its nutrients and minerals. Also, you may want to recharge used soil with compost to add nutrients and help the soil hold water.
Plastic vs. terra cotta
Container materials have different moisture-retaining qualities. Plastic may not be as pretty, but it holds water better than porous terra cotta pots. Glazed pottery is a bit better at retaining moisture but can be heavy to handle. Metal containers slow evaporation but heat up quickly.
The best trick is to insert plants in plastic pots within more attractive containers or cachepots, making sure that there is still proper drainage.
Assemble container plants with the same water needs. Don’t plant thirsty tropicals with desert-dwellers. If you hate to water often, look for plants with silver foliage. They usually can go a bit longer without water.
For a lusher look, check out waxy or plump foliage such as dragonwing begonias or moss roses. Succulents are a great idea for lazy waterers. To add a pop of color, combine them with dry-tolerant gomphrena or strawflower.
The smaller the pot, the more you have to water. Those tiny plants in teacups are mighty cute, but seriously?
Mulch your pots
You can mulch your beds to conserve moisture. You can do the same with containers.
Shredded bark or other decorative materials will slow evaporation and give the containers a more finished look. Get creative: You can use small pebbles, seashells or even marbles. Gravel top dressing is especially good for potted herbs. The gravel holds the moisture, while reflecting the heat that keeps the plant crown dry, avoiding rot and fungal disease.
When to water
It’s simple to tell if your pots are parched: Stick a finger into the soil, at least to the first knuckle, and see how far down the soil is damp. If the first inch of soil is dry, it’s time to water.
Water early in the day so your plants can take up as much moisture as possible before the sun is in full force. If you forget to water, and a plant is bone-dry, place the plant in a tub partly filled with water overnight, to let it rehydrate slowly. Don’t fertilize stressed plants.
If your plants seem to be wilting by midday, think about moving them into partial shade or a place where they get only morning sun. Leave those hot western exposures to tougher plants. If you have plants that are constantly thirsty, put them near a spigot so it’s convenient to water them.
Think about automating
If you can’t keep up with the watering or are going to be away, consider a drip irrigation system designed specifically for containers. Garden centers sell inexpensive systems that easily snap together. Use a timer to set a watering schedule. Yes, a drip system can look ugly at first. But as your plants grow, they hide the tubing.
Rhonda Hayes is a Minneapolis-based garden writer. She blogs at www.thegardenbuzz.com.