|What is the best soil mixture to start wave petunia seeds in greenhouse?|
|Use a soilless seed starting mix (Miracle Gro Seed Starting Mix), to start your seeds. Or, you can make your own by mixing by volume:
4-6 parts Sphagnum Peat Moss; 1 part Perlite; 1 part Vermiculite. If you have a source of compost, screen it well and then mix by volume 2 parts Compost, 2-4 parts Sphagnum Peat Moss, 1 part Perlite, 1 part Vermiculite. Whichever route you take, your petunia seeds should get off to a great start. Best wishes with your project!