Answer: I'm glad you're finding helpful advice through our service! Although you can plant your tulips and hyacinth bulbs in the ground without problem in your gardening region, I'd be concerned about their freezing solid if planted in containers and left out on a deck. Rather than take the chance, why not plant them in your containers and set them in an unheated garage? As long as the temperature remains above freezing they will get the winter chill they require without the worry that they will freeze to death. The same advice goes for your dahlia tubers. Keep them cool, but above freezing. With the bulbs, you can take the pots outdoors in March. With dahlias, wait until late April or early May when the weather begins to warm.
I use packaged potting soil. It's all organic, regardless of the brand. Potting soil is a mixture of compost, peat moss, sand, and vermiculite or perlite. Use a major brand of potting soil (Kellogg's, Miracle Gro, etc.) rather than off brands. The major brands are milled a little finer and I think they perform better.
Hope this answers all your questions. Best wishes with your container garden!
Q&A Library Searching Tips