Cosmos

March 20, 2023

Life Cycle	Annual
Zone 5 Treatment	Plant seedlings outside after the last frost
Seedling Care	Transplant within 2 weeks of receiving otherwise the roots can get too crowded and harm the overall health of the plant.
Netting / Staking	Yes, recommended
Temperature Range They Will Tolerate	45-95 degrees F
Spacing/Height	8” spacing48”-60”” height
Soil Preference	Nutrient rich, break up heavy clay soils and amend with compost to allow better root potential
How to cut for maximum blooms	Harvest when buds are cracking but haven’t fully opened. This extends the vase life a few extra days because pollinators haven’t been in the blooms yet. Always cut above a leaf set to encourage continued side shoot growth for more stems. Don’t be afraid to cut deep into the plant. They are some of the most vigorous re-bloomers in the annual cutting garden.
Pinching	Yes, when they are about 12 inches tall
When to Plant if you are NOT in Zone 5	After the last frost
Post Harvest Care	Room temp water with flower food. Take off all of the leaves and foliage. Leaves and foliage of any cut flower should never be submerged underwater because they decay quickly in water and cause a fast build up of bacteria.
Diseases / Insects	Fusarium Wilt – causes the plant to wilt and discolors the stems and foliage. If you dig up the root ball, you will see a pink mass. Treatment – none, throw away the entire plant to prevent spread. Powdery Mildew – white/grey powdery coating on the leaves. Resource for organically controlling powdery mildew: https://www.growingagreenerworld.com/controlling-or-eliminating-powdery-mildew/ Asters Yellow – leafhoppers spread this and you will see yellow mottling on the leaves at the site of infection from the leafhopper. The flowers will start to distort and ultimately die. Treatment – no cure, must throw entire plant away.
Sweet Pea’s Notes	These are the bounciest flowers for bouquets and that is my favorite way to use them. Harvesting can be a HUGE pain if you do not add netting. I’ve been lazy and not done it in the past leading to a LOT of regret when it comes time to tediously harvest. Also, more so than other flowers they seem to HATE being harvested in the middle of the day. Harvest early or late, at the coolest times of the day. This is a rule of thumb for all cut flowers, but cosmos seem to be significantly more affected and will immediately wilt with revival and life support techniques not being very successful.
Vase Life	4-6 days