9 Tips for Watering Potted Flowers in the Summer

If you’ve spent the spring planting a cut flower garden in containers, summer is the time to focus on keeping them looking beautiful and growing well. Along with other regular garden chores, watering your container plants is an essential chore that easily goes wrong.

Overwatering and underwatering will spell trouble for potted flowers, so use these nine tips to help you water your plants effectively and efficiently during the hot summer days.

To get even more guidance for your whole garden, be sure to check out this article, Watering Your Home Garden Through The Season: A Complete Guide.

1. Water your potted flowers regularly, especially during the peak of hot and dry weather

This one may seem like a given, but you’d be surprised how many new gardeners say “I’ll do it tomorrow” one too many times and then find their container of flowers wilted and beyond saving.

Create a hand watering schedule, or automate the process using drip irrigation. You can set it up using a timer so that you don’t even have to remember to go out and give your plants a drink of water.

Just check the system periodically to make sure it’s working and check the soil as the outside temperature fluctuates through the season. If you have a week of scorching temperatures, then you might need to run the irrigation system longer or more frequently than usual.

2. Water the soil, not the leaves to maximize absorption and prevent damage

Plants absorb only minimal moisture through their leaves, so pouring water on them isn’t the best way to provide irrigation. The roots do a much more efficient job, so saturate the soil, not the plant.

Additionally, mildew and fungal disease grow in damp conditions on wet foliage. This is especially true for diseases like powdery and downy mildew, which can hit flowers like zinnias and black eyed Susan.

In addition to proper air circulation, keeping plant leaves dry is the best preventative measure for healthy plants.

You might not know that plant leaves can get sunburned, particularly true for textured or fuzzy leaves like sage or black eyed Susan. Water droplets can get caught on the leaves, and as the sun shines through them, it magnifies the light, causing sunburned spots.

3. Water the plants in the morning

The best time to water is in the morning because you will be providing the plant with moist soil for the rest of the day. The plant can then top off its water stores in the leaves and stems to better withstand the day’s heat.

Also, you’ll lose less water to evaporation if you irrigate during the cool morning temperatures. This is especially true if you rely on overhead sprinklers or hand watering, where the wind and summer heat can wick away water before it even hits the ground.

5. Check the soil moisture level before watering; if it’s wet, don’t water it again for a while

Overwatering plants can be just as bad as underwatering them. Here’s why:

Plant roots hit air pockets as they grow through the soil, which is essential for their growth. If you fully saturate the soil when irrigating, those air pockets fill up with water, depriving the plant of oxygen.

If left in those conditions for too long, the plant can succumb to root rot and die.

A regular watering schedule should take the guesswork out of whether the plants need to be watered or not, but if you aren’t sure, test the soil by sticking your finger in the pot.

• If soil surface is dry but the soil below is still damp, then the plant still has a supply of water to draw on. 
• If the soil surface and the soil and inch or two down is dry, then it’s definitely time to water. 

6. Add mulch around your plants to help retain moisture and prevent weeds from growing

Add a three-inch layer of mulch to the soil surface of your potted plants, and you will reap several water-wise benefits:

• The soil will retain more moisture since it isn’t directly exposed to the sun.
• Mulch will help even out the soil temperature with its insulating effect.
• Soil is less likely to splash up on the plant leaves if you hand water or use sprinklers, which is important for preventing soil-borne disease pathogens from infecting the plant.

Need help choosing a mulch? Read up on your options here: Best (Free!) Organic Mulches For The Home Garden.

7. Move your potted plants into shady areas during extreme heatwaves

Even with daily watering, a potted flower can overheat if there is a heatwave for an extended period. The pot itself can get very hot and transfer heat to the soil, damaging plant roots.

Plus, the direct sun can burn and wither plant leaves during the peak daylight hours.

You may end up needing to move your pots to a shady area, perhaps under a tree on a covered patio, to protect them until the sun has gone down or the heatwave has passed.

8. Use plant saucers to maximize water absorption, but don’t leave standing water

If the soil in the container has gotten very dry, it can be hard for it to absorb water right away. This is called being hydrophobic, and it’s common with potting mixes that primarily contain peat moss.

Use a plant saucer or water tray under your container if this happens. As you water the plant, the water will run out of the drainage hole in the bottom of the pot. The saucer will catch the water, and the soil can wick the moisture back up and rehydrate itself.

Once an hour or so has passed, dump out any leftover water. At that point, the soil is fully saturated, and leaving it in standing water won’t do any good.

9. Don’t rely on rainfall and risk your flowers drying out

If you live somewhere with regular summer rainstorms, it might seem like a good reason to shut off the irrigation system for the week. Not so fast.

A mature plant’s foliage can block most of the rain from percolating down to the soil; most of the rain will probably bounce off the leaves or drip off the ends that extend out past the edges of the pot, resulting in the soil not getting much water at all.

Don’t take any chances that the soil could dry out. Check the soil yourself after a rainstorm, and if it’s not evenly damp, then keep your drip irrigation system on or be sure to hand water if that’s your preferred method.

FAQ

Should I water potted flowers every day?

Potted flowers do not need to be watered every day unless you are in a dry spell or a heatwave. Frequent, shallow watering is detrimental because it encourages shallow roots, making the plant vulnerable to damage when the top few inches of the soil warm.

If you are indeed in a heatwave, it may be necessary to water plants daily until the weather cools.

There’s more to know about daily watering. Read it all here in this article, Daily Water For The Summer Garden? Not Necessarily.

How much water do plants need every day?

Unless it’s very hot outside for days or weeks on end, container-grown plants don’t need to be watered every day. Most plants should be watered once or twice per week for a total of one inch of water per week.