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How Much & How Often to Water Sunflowers: Requirements, Tips, & FAQ

sunflowers in the garden

Gardening is one of the best ways to get in touch with nature and improve your mental health, and learning how to care for new plants is always a blast. Sunflowers are a cheery addition to any garden or yard, and they’re fairly easy to grow, too. As with any plant, sunflowers have particular watering needs to grow tall and strong, but how much is too much?

garden flower divider

Sunflower Watering Requirements

Watering Lawn
Photo Credit By: creative2usa, Pixabay

After germination, sunflowers only need about 1–1.5 inches of water per week to thrive. This comes out to about 2 gallons per week. Germinating sunflower seeds need a bit more. We’d recommend about 2–2.5 gallons of water per week until the seeds fully sprout, and you can slightly reduce watering after that.

However, daily watering isn’t necessary. Instead, allow the soil to dry out between waterings. If the soil starts to crack, you’ve waited too long. Water them deeply while taking care not to flood the soil. You can tell when to stop if the soil is thoroughly saturated and water is starting to pool around the base of the flower.

But when should you water them? Preferably before noon, when the sun is high and temperatures are at their hottest. This will give the flower ample time to absorb the water through its stem before the sun steals it away via evaporation.

Can Sunflowers Survive on Rain Alone?

It depends on your climate. Sunflowers need a moderate amount of water, but they don’t love persistent downpours. Ideally, a nice shower or two per week should satisfy any sunflower. If your area doesn’t get much rainfall during the summer, you may want to supplement by watering them during dry spells.

sunflowers in pots
Photo Credit By: BBA, Shutterstock

Sunflower Watering Tips

Watering plants isn’t that complicated, but some aspects can be tricky to figure out. Below, we’ve compiled some of the handiest tips that will help your sunflower flourish.

  • If your sunflower’s stem starts to turn brown, it may be receiving too much water. Lower the amount of water it gets weekly and see if that helps.
  • While growing, the leaves on an underwatered sunflower may turn brown. If you see this happening, increase the amount of water you’re giving your flower.
  • After the flower reaches maturity and the head turns brown, avoid watering it.
  • For sunflowers in pots, ensure that the pot has drainage holes to prevent water from stagnating.
  • If the weather predicts rain, hold off on watering your sunflower. Too much water is worse for your flower than the occasional dry spell.
  • If you can’t water your sunflower in the morning, opt to water it in the evening when temperatures are cooler and the sun isn’t as intense.
  • The main sign that a sunflower isn’t receiving adequate water is drooping and the flower turning brown.
American giant sunflower
Photo Credit By: ulleo, Pixabay

Can You Overwater a Sunflower?

Yes, you can give a sunflower too much water. If the soil is well-draining, overwatering by a little bit isn’t that bad for your flower. However, intense storms can dump a lot of water on your sunflower and even kill it. You can also overwater them yourself if you don’t carefully measure how much water you’re using.

Overwatered sunflowers aren’t a lost cause. You can move overwatered sunflowers in pots to a more shady, well-ventilated area to help them dry out, and consider poking more drainage holes in the pot if possible.

The most serious risk for overwatered sunflowers is fungi, which love stagnant water. To prevent potentially fatal fungi from infecting your sunflower, treat them with a fungicidal product as soon as you notice that they’re receiving too much water.

garden flower divider


Sunflowers need a lot of water when they germinate, but only a moderate amount of water once fully grown. To make sure your sunflower doesn’t get too little or too much water, utilize some of the tips listed in the information above.

Featured Image Credit: Piqsels


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