Wildflowers can be sown at various times of the year, depending on when you want to see the flowers.
To plant wildflowers in the fall for early spring blooms:
Wait until after a “killing frost” (a hard frost) to plant your wildflowers - this will keep them from germinating too early
To plant wildflowers in the spring for late spring/early summer blooms:
Wait until all frost danger has passed, then plant immediately! In areas with a milder summer climate, you can plant wildflower seeds in summer for fall blooms - areas with high heat and drought will not allow the seeds to sprout.
Wildflower mixes contain annual, perennial, & biennial varieties. Annual - These plants will grow, flower, go to seed, & die in one season. The seeds will usually spread themselves, so you will see the same flowers come back from new plants. Perennial - These plants come back year after year. They develop deeper roots and will spread out more and more each year. They are also a bit slower to sprout/bloom than the annuals in the mixes. Biennials - Sprout and make plants one year, then will bloom the next year. Then they will self-seed and come back to start over again the next spring.
Wildflowers can grow almost anywhere, including among grass, but if you want a good, thick bed of flowers, prepare a space. Clear away plants and grass, till the ground down just a few inches. Make sure that your area gets plenty of sun and has good drainage.
We do NOT recommend fertilizing the soil unless it is lacking in specific nutrients (get a soil test to tell you exactly what is needed). When you spread your wildflowers, broadcast them over your area. To prevent seeds from blowing away, you need to press them down into the soil. If you are planting in the fall, cover lightly with soil and a light layer of mulch - you do NOT need to water this over the winter. If you are planting in the spring, avoid too much covering, so no mulch, and water in the seeds.
Once you see sprouts, keep the area well watered in the first 4-6 weeks until all the plants are well established. After this period, the area can be watered much less frequently, unless conditions are dry and your plants start to look limp.