Cosmo – Hinomaru

Germination

Start seeds 4-6 weeks before your last average frost.  Sow 1/4″ deep.  Kept at 70-75° F, germination is in 7-14 days.  Transplant into the garden 9-12″ apart.  You can also direct sow seeds after all danger of frost by sprinkling seeds on the desired area and using a rake to work them into the soil lightly.  Make sure to keep the area moist until germination.

Growing

With tall cosmos, when plants are about 12″ tall, pinch off the main stem to encourage branching for bushier plants that will produce more flowers.  For shorter cosmos, pinch when plants are about 4-5″ tall.  Taller varieties of cosmos may require staking.  While mature cosmos are drought tolerant, they will produce larger, more abundant flowers if they are watered regularly.  Please keep in mind that cosmos thrive in poor soil.  Fertilizing cosmos will lead to strong plants with very few blooms.  If your plants seem to be struggling, you can give them a boost with Dyna-Gro’s Bloom 3-12-6 formula. Cosmos do not do well in rich soil and will become leggy and weak.  They also prefer neutral to alkaline pH and warm weather.  Cosmos will self-sow prolifically, so make sure to deadhead spent flowers to avoid this.  Deadheading will also encourage more flowers and prolong the blooming season.