"Dahlias like vegetable fertilizer, which is typically low in nitrogen (the first number on the fertilizer package.) Use 5-10-10, 10-20-20, or the best would be 0-20-20." Dahlias need more nitrogen than this. There are posts on this forum about the "low nitrogen myth" Nitrogen washes out of soil and needs to be replenished every year. At the Bonneyville Dahlia trial garden sponsored by the American Dahlia Society they only use nitrogen as the fertilizer because their soil tests say that they have adequate pohosphorus and potassium in the soil. Without doing a soil test, most people should use something like the 5-10-10 or 10-20-20 but do so in moderation and do so several times in smaller amounts until about August 1st. Many people who have used fertilizer in their flower beds for several years will have a build up of phosphorus and should use fertilizer with low phosphorus. By the way, the new "greener" fertilizers are lower in phosphorus.

A quick response.... Height could be all of the above: variety, sun, soil, water ect. 'Dinnerplates' is a category of dahlia, not a specific variety and they will all grow differently, bloom at differenet times, grow faster/slower ect.... You should plant them at least 1/2 of their height apart so a 4' dahlia should be planted at least 2 feet away from their 'neighbor'. I would just keep them where they are this season as long as they are 12" apart, if not, I would dig them up, as big as tuber-ball you can and water them well before and after the move. I pinch mine all season. I pinch early to promote branching and stocky plants and later to promote larger blooms. So you can pinch anytime, but too much pinching will delay buds if you do not pinch properly. Search this forum for pinching tips, there are many great threads on here relating to that. I hope that helps No need to worry, they are tough and you will get a great show even though you are a bit late starting them. Keriann~

My experience tells me that 1) dahlias are very different in their growth habits 2) Height is unpredictable 3) Bloom times are very different. It all depends on the varieties you are growing. Generally speaking, larger blooms take a longer time to develop; and cactus varieties generally bloom quicker. But even that is not a science. As far as plant height - I planted all mine within about 3 days; and now have some plants just peaking out of the ground; and others with buds!! I'm dabbling in exhibiting dahlias this year and have tried to read everything under the sun about how to time out dahlias for shows. I haven't found any solid way to predict yet. The best advice that I have learned is to just grow a variety and take really good notes (planting dates, topping dates, first bud, first bloom, # of leaf pairs you left when you topped, # of leaf pairs from bottom of plant to bloom etc, etc,....) My wife makes fun of my excel spreadsheet dedicated to my dahlia plants. There is a payoff - If you grow the same varieties the next year you can plan when to plant, when to top etc. I'm following more of a plan this year according to some of the varieties I planted last year (i.e - if it took 57 days for a plant to bloom after I topped it; I know that I should top that variety about 57 days before the show) That's probably more info than you needed unless you really want your dahlias to bloom at a certain time.

During a very warm summer, they may not grow too much. But when it cools down, they will put on lots of growth and reach their normal height.