Our Guide to Growing Dahlias

Planting

You can plant your dahlias when the soil temperature is consistently 60 degrees or warmer. Dahlias like full sun (8 or more hours a day) and rich well drained fertile soil so we recommend amending your soil with a good 2-3" of compost or manure prior to planting. Plant dahlias 6" deep with the growing eye facing up, spacing them every 16-18". Snails and slugs love the young green growth so we apply bait at planting time. We like to use Sluggo Plus which is an organic option also safe for kids and pets. It protects against earwigs too which love to eat the flowers. Reapply throughout the season.

Fertilizing

Dahlias have all the energy they need to get going stored in the tuber. Once the plants are about 12" tall we begin feeding with an organic liquid fertilizer and continue every 4-5 weeks through the season. Dahlias do not like high nitrogen fertilizers so be sure to use a fertilizer that is high in phosphorus and potassium. You can also plant with a dusting of bone meal, but be careful not to apply too much as you risk burning the roots. Remember that everyone's soil is different. Clay soil might hold on to the nutrients for a longer time while dahlias planted in a very sandy soil might require more frequent feeding. The best option is to get a soil test, but if not, just remember to not overfeed your dahlias with high nitrogen fertilizers.

Watering

Dahlias love water but only once they have sprouted from the ground. After planting dahlias, do not water as this can lead to the tuber rotting. However, once they have sprouted from the ground they will benefit greatly from a good soaking with soaker hoses or a drip irrigation system once every 3-4 days during the heat of the summer.

Pinching

Once dahlias reach about one foot tall they will benefit greatly from pinching. By cutting 3-5" inches off the center growing stalk, you will encourage the plant to branch which will increase both the number of blooms on your plant as well as the stem length.

Staking

Most dahlias over 3' - 3 1/2' tall require staking as do those with large heavy blooms. We like to put a stake in the ground at the time of planting before even placing the tuber in the soil. This avoids the need to pound in your stake at a later time as doing so may damage the tuber or its root system. Once the dahlias are around 2' tall we will gently tie the center branch to the stake and repeat as needed as the plant continues to grow.

Harvesting

Harvest your dahlias when they are almost fully open and put in cold water immediately. You can expect a vase life of 4-7 days. We have found that by placing stems in almost boiling water and allowing the water to completely cool the stems you can also extend the vase life.