Watering Dahlias (2024)

FAQs

How often should dahlias be watered? ›

Dahlias require deep watering 3-4 times a week by a soaker hose or sprinkler for 60+ minutes each session when planted in the ground, as the water must reach the roots, which are 8-10” deep or watered at least 1-2 times daily if planted in pots.

💧 Identifying Symptoms of Water Stress

Limp or blistered leaves are the tell-tale signs of over-loving your Dahlia with water. It's a common slip-up, given their tubers' aversion to soggy conditions. Overzealous watering can lead to a sad, waterlogged plant with potential root rot.

Dahlias grow best when they receive a consistent supply of water. Drip irrigation is ideal, as it directs moisture to the root zone while keeping the foliage dry. If you are hand-watering, it's best to water deeply once or twice per week.

If your dahlias are part of your landscape and already get watered by overhead (yard) sprinklers that works just fine. Overhead watering can sometimes help with deterring pests, but it can also lead to stem rot if water gets inside of the plant stem after a flower has been cut.

Misting Dahlias for Afternoon Heat Relief

Dahlias are said to benefit from a misting or light shower with the garden hose during the hottest part of the day. Interestingly, the water evaporating from the leaves supposedly will help to cool the plant down.

🌼 Yellow Dahlia leaves signal aging or distress, like nutrient deficiencies or overwatering. Soil testing guides nutrient corrections; use fertilizers and supplements as needed. 🚿💧 Balance watering and drainage, and treat pests/diseases promptly to maintain health.

It can be tricky to tell the difference between underwatering and overwatering because some of the signs can seem similar. Whereas dark brown or blackened leaves can mean overwatering, light crispy leaves can mean underwatering, especially if the soil is dry.

Nutrient Deficiency

If your dahlia's leaves are yellowing, it may be due to a lack of nutrients in the soil. If your dahlia leaves have green veins with yellow leaf tissue, they are quite likely suffering from some kind of nutrient deficiency.

Dahlias don't like to get too hot or too dry. Their leaves look a tad tired, and they have trouble producing as many flowers. The best way to water is a drip pipe – less wasted water and it goes straight to the root. The easiest time to lay down the drip hose is when you plant the tubers.

I place the trays in a warm, sunny location like a south facing window, a greenhouse or cold frame. The warmth and sun will tell the tuber it's time to start growing.

What is the best fertilizer for dahlias? ›

Should I fertilize my dahlias? If you choose to use a fertilizer, go for low nitrogen and high in potassium and phosphorus, something like a 5-10-15 or 5-10-10. Fertilize within the first month of planting, then repeat again 3 to 4 weeks later.

A good rule of thumb is that your dahlias should receive 1” of water every week. In the heat of summer, dahlias will require more water especially if it is warm and dry. When they are actively growing and blooming, dahlias will need more water. Dahlias grown in pots will require more frequent, daily watering.

Dahlias rank high on the list of plants that dislike weather extremes. They prefer temperatures that vary no more than about 20 degrees: 70-80°F during the day and 60-70°F at night. When temperatures rise above 85°F or nights don't cool down, dahlias may begin exhibiting signs of stress.

Full Sun Is Usually Best

But if the sun is too hot, dahlias get stressed and may stop flowering. If you live in the southwest where the sun is especially intense, consider a planting location where your dahlias will get direct sun for most of the day, but some amount of shade - especially during mid and late afternoon.

Dahlias love to be in a sunny location— an area that receives at least 6-8 hours of direct sunlight is preferred. Dahlias will also grow in shady areas but generally will be taller and require more staking and care. Dahlias love to be in the dirt. The dirt is a friend to Dahlia Tubers.

If you feed and deadhead regularly your dahlia will keep producing flowers all season long, and there will be plenty of blooms available, just in case you need them to preserve marital bliss.

Full Sun Isn't Always Best

Dahlias are sun lovers and more sun usually means more blossoms. But if the sun is too hot and temperatures are too high, the plants may stop flowering. If excess heat is a concern, choose a planting location with half day rather than full day sun.

Watering: While the plant is developing roots, let the soil almost dry out before watering again. The copolymer crystals will prevent the tubers from drying out. If the soil is kept too wet before the roots and top growth get a good start, the tuber may rot. Water the plants after adding more soil to the pot.