Watering Dahlias with Drip Irrigation vs. Overhead Sprinklers in a Drought
Updated March 13, 2025
The growing season of 2022 will fondly be looked back on as our first year of expanding into our new flower field and property. 2022 will also hold a space of loathing in my heart as the year of extreme drought conditions, stunted plants, and soil as hot and dry as the desert. In this post, I’ll discuss what happened to our dahlias during an extreme drought in 2022, and setting up overhead sprinklers instead of drip irrigation.
what happens to dahlias in a drought?
Drought is a phenomenon that now occurs more often than ever throughout the world and across the United States, and the worsening effects are caused by climate change. In our Great Lakes Region, we are geographically blessed and surrounded by large bodies of water. Because of this, we tend to experience drought at a much lesser rate than other regions. Drought does occur though, and as the effects of climate change become more extreme, so will drought conditions. As farmers, it is important we take this information seriously and start formulating climate change mitigation strategies on our farms, but that’s a topic for another post.
Related: This is Why We Grow a No-Till Flower Farm
So in 2022, a drought year for our normally average rainfall region, was of course the year I decided to skip drip irrigation on the dahlia patch.
side note: our dahlia-growing manifesto
I recently wrote a 216-page book all about growing dahlias called Growing Gorgeous Dahlias: The Regenerative Grower’s Guide to Abundant Dahlias from Garden to Flower Farm, and it includes an entire chapter section on setting up a watering system for dahlias, from soaker hoses and drip irrigation to overhead sprinklers for both backyard gardens and farm fields. For both beginner and experienced growers, I recommend getting yourself a copy or asking your library to purchase one for you to borrow!
do dahlias need consistent water? (yes!)
There are some flower farmers on Instagram who claim that irrigating dahlias is not necessary and you can grow a perfectly productive, healthy field of dahlias with no added water through the whole season. This is a load of bull. It is basic knowledge that dahlias require a lot of consistent water to grow into healthy, robust plants (average 1” of water per week). Let it be known that when I didn’t irrigate my dahlias, I was not intentionally taking this bad advice, I was just too busy and had bad time management, all the while knowing that I should have irrigated the dahlias.
Related: Will Deer Eat Your Field of Dahlias?
The first month of zero irrigation in our dahlia patch went fine. Typically we don’t water the dahlias until green growth appears out of the ground, which takes anywhere from two to four weeks anyway. The month of June went by, it rained a few times, and we were doing well.
Then July came around and we went well over a month without rain. It also hardly rained the entire month of August. This was during the period of growth when the dahlias were beefing up their green base and really, really needed water for proper growth and bud production. Out of desperation, I hooked up a hose to our newly-installed water line and spent hours (HOURS, DAYS) hand watering 900+ dahlia plants.
Related: Vole-Proof Tulip Planting
Here’s what happened to the dahlias during a drought with no irrigation:
The dahlias grew slower than slow… the slowest they’ve ever grown! Therefore, harvest was delayed.
The dahlia plants were stunted.
At times, the plants were actually wilting in the field because they needed water so badly (plants should never get to this point of dehydration if you want them to be productive and able to naturally repel pests and disease).
I, and my partner, wasted hours of our lives hand watering with a hose.
It stressed me out. Whenever possible, farmers should always try to mitigate stress when possible, and having an irrigation plan is one way to do that.
If I’m being honest, had I set up drip irrigation in the first place, I believe the plants still would have been thirsty. They still would have become stunted over the drought period. Nothing can cure a thirsty plant like rain. Municipal water out of a hose (which is what we irrigate with on our farm) cannot do what rain can; that is to say, municipal water will merely keep the plants from dying. It will not provide trace minerals and the goodness that pure water falling from the sky does.
The great news is, the dahlias did end up producing flowers and growing some of the most spectacular blooms we’ve ever had coming out of the dahlia patch! I owe this success to my last-minute plan to set up two overhead sprinklers in the field.
Related: Fertilizing and ‘The Law of Return’
overhead watering sprinklers for dahlias
I ended up setting up overhead sprinklers in the dahlia field and it helped immensely with keeping the plants hydrated. The plants responded almost immediately to a regular watering schedule and it freed up the need of hand watering with a hose and laying/removing drip lines.
The happiest part of this story is that not laying drip lines forced me to put overhead water in the field, and I ended up loving it. Going forward, I plan to water my dahlia patch using sprinklers instead of drip lines, or at least doing a mix of both. Not only is it super easy to set up, but wet leaves also deter spider mites, who thrive in hot, dry conditions. Overhead watering also attracts birds, who work on eating caterpillars and other pest bugs off the plants.
The exact sprinkler heads I used are these: Orbit 27793 T-Post Sprinkler Attachment on Amazon. Two of these heads, attached to 10’ T-Posts, covered a 50’ x 120’ area. I attached the hosing to a timer and set it for every-other day at 4:00 AM for 20 minutes. When it actually did start to rain again, I used the rain delay option on the timer and eventually by mid-September turned the system off altogether.
In 2025, we are switching to wobbler sprinklers and will report back on their efficiency.
Overhead Sprinkler Supplies We Used:
The moral of the story is...
Dahlias need irrigation (1” of water per week), regardless of whichever watering system you decide to go with. Don’t heed stupid advice from every flower farmer on Instagram (ie. “dahlias don’t need to be watered”).
Extreme drought will stunt plant growth no matter what irrigation plan you have in place.
We love overhead sprinklers on dahlias!
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peace, love, and regular rainfall for all,
Fran Parrish
