What's wrong with my cosmos flowers?

Question

I live in New Mexico, and it's VERY hot and dry right now(strong sun & high elevation). My cosmos keep dying--turning wilty, then brown, no matter how much water I give them, or whether they're inside or outside (I live in an apt., so they're in pots). What do you advise?

Answer 1

cosmos need poor soil and little watering after they have established themselves. the problem is called canker. it is a fungus .it appears when fungi in the soil attacks the plants water conducting.take out the dead flowers and throw them away. if you still have a sizeable amount of healthy ones left,thin them out as much as possible. the fungus hates air circulation.then dig in lots of compost into the soil.it gives off ethylene gas that will discourage the growth of fungus. to keep them fungus free spray them once a week with a solution of 3 tbsp of apple cider vinegar in one gallon of water.spray them in the morning.night time spraying leaves them wet and the mold likes wet.

Answer 2

Hi, there,

I live in hot West Texas so I know your weather conditions are about like mine. I don't think the roots of your comos are getting the water. Water has to flow out the bottom of containers for flowers to be watered correctly.

'Bright Lights' cosmos are bred for our hot dry areas. I grow them each year in containers. They are about three feet long and a foot wide. One foot deep.

I have also grown them in larger round containers that are 14 inches across the top of the containers. These take about 25 lb bag of potting soil each.

Do not fertilize Bright Lights, and only water when the soil is dry. You can test this by sticking you finger down into the soil a couple or more inches. Flood with water if dry. Let the water flow out the bottom of the containers. This will get the roots watered. Than do not water again until dry.

Bright Lights needs several hours of sun in order to bloom

As the flowers start fading, cut or pinch them off. This will give you more flowers.

If you want to collect seeds for next spring's planting, do not cut off the flowers starting the first of August. Let them go to seed. Let the seeds turn dark brown/black on the stem and then cut them off and let them dry for a week or more. Store them in a dry place such as a box or an envelope.

I use Miracle-Gro potting soil. I use the one with plant food already in it. I also use moisture crystals, or buy Miracle-Gro with moisture added. This will keep you from having to water so often and will help keep the roots watered.

Happy gardening to you.

Answer 3

Containers here are the pits! Due to our hot, dry conditions the plants need water at least daily and sometimes twice......depends on the pot size. Larger seem to hold the water.......until the soil shrinks back from the sides and not allowing water to penetrate the soil........check the soil for shrinkage.

Also check the soil......could be the whole root ball is not getting wet with each watering..........and I assume the pots have drainage so they don't water log the plants.

Insects.....spider mites can wipe out a garden, either in the ground or in containers, in a matter of days. I wonder if you problem might also be mites.....the damage mimics drought injury.

Have you tried adding the water holding gels to the potting mix? They may help.

Also the pots themselves get pretty darn not which the roots hate. Double potting, that is putting a pot within another pot helps keep the roots cooler.

Answer 4

i advise trying another plant.. it sounds to me like, because the plants are in pots, they are drying too much.. too fast .. you would need to keep soil moist...NOT WET... for the entire season, which might mean a qt of water every hour during the day.,, who has time for that?

try something different although cosmos' are gorgeous plants to have:)

happy gardening

Answer 5

Mycosmos