How Much Water Do Sunflowers Need?

Sunflowers are the ultimate embodiment of summer. With their large, dramatic heads. Bright colors that range from Sunshine yellow through to deep purple. They are a popular garden bloom that can bring joy to your garden every year (although they are only an annual flower). 

But how much water do sunflowers need? Sunflowers need about an inch of water every single week, although they do best with frequent watering. That being said, younger sunflowers should be watered more often than more mature ones, which are able to leverage more water in the soil due to their longer, established roots. 

In doing so, these flowers will reward you, blooming beautifully at the height of our warm summer months. 

They can be planted as stand-alone blooms, or if you are ready to make a statement that evokes the feeling of romantic trips through the Italian countryside, you can plant them in as large a collection as you wish.

Nevertheless, if you are preparing your garden for a slew of these sunshine blooms, read on to find out exactly how to water these magnificent blooms—keeping them sunny all summer long.

How Often Should Sunflowers Be Watered?

Sunflower seedlings will need to be watered every couple of days, whereas mature sunflowers have expansive and deep root systems, which means they only need to be watered once a week.

Sunflower seedlings can be very delicate. 

Their roots systems, although growing fast, will not be established and cannot reach far enough down into the earth to reach the water. 

So they need to be watered regularly, preferably every couple of days. 

Although if there has been a very dry, warm spell, they could need watering more often.

Keeping an eye on the moisture levels in the soil will give you a good idea as to whether your seedlings will need a little top-up. 

Dry, dusty soil could indicate a lack of available water; keeping the surrounding soil damp but not sopping wet will ensure your little sunflower babies have enough water to support their early growth.

As for mature sunflower plants, they can adapt to drier and slightly harsher environments. 

Sunflowers have an incredible roots system that grows fast and very deep. 

So they can access water in the soil even if the topsoil seems much too dry. 

Mature sunflowers need around 1 inch of water every week, so a good 10-20 minute drip soaking with a hose once a week should be plenty. 

Just make sure the surrounding soil is damp and not muddy.

How Do You Know When A Sunflower Needs To Be Watered?

By keeping an eye on the surrounding soil of your sunflower and the physical condition of your plant, you can tell whether they need a little extra drink of water.

Although sunflowers are considered a flower suitable for beginners, they can be very fickle at times. 

They don’t like to be underwatered, but alternatively, they really hate overwatering. 

If the soil surrounding your sunflower is dry, crumbly, and dusty, your plant will definitely need some extra water. 

Like many other plants, drooping can also be a sign that your sunflower is getting very thirsty.

Can Sunflowers Be Overwatered?

Although your sunflowers need regular watering, they are very susceptible to being overwatered. Overwatered sunflowers can die very quickly and be completely unsalvageable, so keeping an eye on how much water they are receiving is important to keep these big and beautiful blooms thriving during their flowering season.

Sunflowers absolutely hate constantly having ‘wet feet,’ and overwatering can even cause root rot which will kill your sunflower with no chance of recovery.

Some signs that your sunflowers are being overwatered are:

  • Drooping petals, leaves, and flower head.
  • Brown rot that starts at the base of the stem.
  • Discoloration on leaves

Because of their fickleness towards overwatering, they need well-draining soil. 

If you have heavy, compacted clay-type soil in your garden, it may not even be a case of overwatering your sunflower, but that excess water hasn’t got enough room to trickle away, leaving your poor sunflowers roots in a pool of soppy mud, which will eventually lead to rotten roots and stems.

How Do You Water A Sunflower Plant?

Once your sunflower has developed a mature roots system, it will be ever so slightly more tolerant to drought conditions.

However, if you are watering sunflower seedlings, they will need a very regular watering routine – every other day unless the soil is dry to the touch and they may need water a little more often. 

Mature sunflower plants will need a healthy 1 inch of water once a week at the height of their flowering season.

Sunflowers, however, love routines. 

They love regular watering at the same times of the day. 

So if you are watering a mature sunflower, ensure you are watering them on the same day every week and at the same time. 

We suggest early in the morning before the sun has fully risen so that your water gets to soak fully into the ground with evaporating in the sunlight.

When you are watering your sunflower, you have to make sure that you don’t get water on the stem, leaves, and flower head. 

Wet plants can singe in the heat and bright Sunshine. As much sunflowers love the summer sun, they don’t want to be scorched by it. 

In the couple of weeks before your sunflowers’ heads blooming you can add a nitrogen-rich plant feed to their water. 

Giving them all the nutrients they need to flower with really impressive blooms.

Sunflowers have a very short flowering season, so they have to grow incredibly fast. This means they can struggle to get all the nutrients they need. 

Nitrogen deficiency is one of the top killers of our sunflowers. 

Nitrogen is the element that makes our sunflowers’ leaves look green and healthy. 

The most obvious sign that your sunflower is struggling to get all the nutrients it needs will be when its leaves start to go yellow.

Nitrogen-rich plant feeds are easy to purchase in your local garden center. 

There will also be application suggestions on the bottle. Stick to the recommended levels on the bottle, as too much nitrogen can be bad for your sunflowers as well.


Sunflowers are the dramatic gardeners’ flower of choice. 

Not only can you grow the common but very popular Helianthus Giganticus (The giant sunflowers we are all accustomed to), but you can find dwarf versions, and they all come in a wonderful variety of colors. 

So yellow isn’t your only option anymore. 

They may be a little particular when it comes to their watering needs, but a steady watering routine will help your sunflowers be the best on the block.