The temperatures that allow for autumn planting correspond to United States Plant Hardiness Zones 7 and higher. [1] X Research source If the winter temperatures in your area fall below -20ºF (-29ºC), consider planting the cold-resistant Iceland poppy.
If you will be planting poppies in autumn, then you don’t need to plant in stages.
Purple poppies may retain a brighter, more attractive color in partial shade than in full sun. [2] X Research source
Avoid planting the seeds in clumps, which will interfere with growth. If you are planting poppies across a large area, take handfuls of seed and sand mixture and throw them out away from you as you walk across the garden or field.
Avoid watering plants during the early afternoon, especially in sunny weather. The heated water can burn the leaves, and it may evaporate before it can be absorbed.
Do not pull the plants out as this may disturb the root systems of the neighboring poppies. Spacing plants out in this manner may also reduce the chance of mold and pest attacks, due to good air circulation and lower frequency of transmitting these problems from one plant to another.
Fertilizers display the balance of nitrogen, phosphorus, and potassium using three numbers. A low nitrogen fertilizer will have a lower first number, for example 2-5-5.
Note that you should not cut off withered leaves from perennials if you would like them to remain healthy and bloom again next year. [7] X Research source Allow the leaves to die naturally, and hide the brown color with longer-blooming flower varieties if you wish to keep your garden colorful.
If you must transplant adult, perennial poppy plants, try to do so in late summer, after the most active growth period but before they begin to seed. [9] X Research source
More detail can be found in the section on planting seeds.
