It has been 60°F in Northern Virginia for two days, but snow is expected in 48 hours. While I feel the need to get started with the tubers, I had the same feeling last year. The tubers were still sleeping and stayed that way for several weeks. Some growers disagree, the eyes will show with warmth and slightly moist soil. It is up to you. I will wait about another six weeks, and then move the tubers from bags to trays.
I received a message today from a friend who wanted to grow dahlias. She observed that her yard is mostly shady. There is one aspect of dahlia growing about which virtually everyone agrees. Dahlias need at least a half-day of sun to grow and bloom. I so regret having to tell folks that at garden sales—particularly when they are excited about dahlias.
I sent some soil away for a soil test. The report showed a pH of 7.3, phosphorous was off the chart, and potassium was low. This is typical for my patch. I will add a top dressing to reduce the pH to below 7. When I fertilize in May, I will apply a time-release with little or no phosphorus. I am not afraid of nitrogen at the beginning of the season. It is water soluble. Consider this somewhat pro-nitrogen web article and conversely, see low nitrogen advice
here.
It is useful and not too late for a soil test. Your local garden center or Extension Service can point you in the right direction. Find testing information by state on this webpage.
Dahlias are heavy feeders and the quality of the soil in the patch or container cannot be overlooked. I have some containers on the patio. It is easy to leave the soil alone for another year but so much better to empty at least half, loosen the rest, and refill the container with good quality potting soil.
Your outdoor garden raises a different question: should I till or not till? Some experts believe tilling aerates the soil and provides an opportunity to work in fertilizers, organic or chemical. Farmers have tilled for centuries. Others say that tilling upsets the microbial life of the soil and brings dormant weed seeds to the surface. The debate goes on...
