This time of the year, most areas are safe to plant dahlias. The soil temperatures have risen to the 60 degrees needed to plant and spring is slowly turning towards summer. Within the last week in WA State, we have planted both farms and always breathe a sigh of relief when the crop is planted and they are producing tubers for next season.
What do you do after you plant:
Northern Climates:
Add an organic fertilizer and scratch in to the top few inches of soil. Water so it can start dissolving.
Add Compost – If you did not add compost to your soil when you planted, now is the time to do just that. Lay a 2″ – 3″ layer over the area you planted. This will build your soil nutrients and will better retain the moisture over the summer months.
Watering (dry climate) – your dahlias need some moisture in the soil to start growing. If you live in a very dry climate, you’ll need to add moisture to the soil. Water once a week so the soil can retain that moisture.
Watering (wet climate) – If you live in a rainy climate, don’t water the rain will give the soil everything the dahlias need. It’s better to keep them on the dry side then the wet side before the sprout has emerged from the soil.
Once the dahlia sprout is 5″-6″ in height, begin to deep soak 2-3 times per week. Hand watering is never enough, use a soaker hose and let it run for 45 minutes to an hour. Dig down and see how far the soil is moist, you want to make sure you water long enough that the water reaches the tubers.
Southern Climates:
You’ve had your dahlias in the ground for possibly 8-10 weeks now. They may be starting to bloom:
Fertilize with an organic fertilizer or a 5-10-10 fertilizer
Water 2-3 times per week. Hand watering is never enough, use a soaker hose and let it run for 45 minutes to an hour. Dig down and see how far the soil is moist, you want to make sure you water long enough that the water reaches the tubers.
Cut your blooms – the more you cut your dahlias the more they will bloom
Organic fertilizers
If you can find Espoma fertilizers, Bulb Tone is what we like to use as an organic fertilizer.
Espoma Bulb tone
Organics are slow release and will slowly release nutrients all season.
For more information on all the Espoma fertilizers, visit their website at www.espoma.com
Other Beneficial fertilizers to add to your soil:
Iron: will cause the leaves to be greeener. Soils that are low in iron cause the dahlias to have slight yellowing to the veins.
Epsom Salt: added every couple years. Soils low in magnesium can cause yellowing of the veins.
Soil Testing:
Basic soil test kits will measure N-P-K, N-Nitrogen, P-Phosphorous and K-Potassium and will measure the amount of nutrients you have in your soil. They can also tell you where your soil pH is at. The pH level in your soil is important because it can effect nutrient uptake by your plants. If the pH is very high or low, the amount of fertilizer that plant will absorb can be hindered.
Why your soils pH level is important:
Soil pH will control how well your plants can take up nutrients. If your pH is really high or really low, it will not allow the plant to absorb the nutrients in the soil even though those nutrients are there. pH has a range from 0-14, with 7 being neutral. You want your soil pH to be about 6.3 – 6.8 or so for dahlias because dahlias like ‘slightly acidic’ soil. Most soi
ls will fall between the range of 6-8. 6 would be more on the acidic side and 8 would be more on the alkaline side. Most acid soils are found by trees that drop their needles every year and cause the soil to be more acid. Soil test kits can be found at any home improvement or garden store this time of year.
What to do if your soil is too acidic or too alkaline:
Too acidic: Add Lime to raise the pH level in your soil.
Too alkaline: Add Ferrous Sulfate (iron) to lower pH
The pH level in the soil is what would cause a hydrangea to be pink or blue in color. By adding lime to your soil and raising the pH, the hydrangea will be pink. By adding ferrous sulfate (iron) and lowering the pH, this will cause the hydrangea to be blue.
The process of changing the pH levels won’t happen overnight. Often it will take months up to a year to see the full results. But knowing now, and taking steps to correct it will grow a better garden in the future. Try to make it a yearly chore, to test your soil.
For more information on Dahlia Care, please visit our Dahlia Care page