The soil needs to be at least 60 degrees. Yes, you can sow them directly in the garden AFTER the last expected frost date, or indoors a couple weeks before last expected frost. Here in zone 7 NC, my last expected frost is approx. April 15th and these have self-sown and germinated as of yesterday, the 28th. For you in zone 4, look for other things in the garden that are germinating that like warm temps such as Sunflowers, and you'll know you can sow. My Roses have formed all their flower buds and are ready to open, so that will give you another sign of when it would be time to sow your Moon Vine. Email me to compare more details in the garden that could give you a hint of when to sow.

Soaking the seeds overnight help them germinate better too. Good luck, they are beautiful in bloom!

~bushpoet

i directly sowed mine and germination occured in less than a week so its OK

For anything in the morning glory family, I always use an emory board to sand one side of the seed until it is light-tan. Then I soak overnight in 1/4" of water, then plant them in dirt. I have had no problems with them.

i am trying now to grow my first moon flower. i soaked them overnight and then put them in my garden....i think one seed is germinating (looks like its coming up) but no others. last year i did morning glories.. didn't soak them and they all came up!! go fiqure!