My latest Instagram posts have spurred many questions on how to effectively support dahlias. I can honestly say that I have tried many methods and as much as I hate my current method, it is the best way, IMO.
So to keep it as simplistic as possible...
How are you going to water? If you think - drip irrigation - then it needs placed now.
Dahlias are a long game project, best to be proactive than reactive so the netting support needs implemented early on, before your plants get too big. Or else the netting support does not help at the base and the plant doesn't grow through the 6" squares as it should. You'll have to manually work the stems through it and that takes oodles of time. I have done it, take my advice!
The netting comes in a few widths and varying lengths. Since my rows are narrow I use 3' wide netting and purchase in 'bulk'. The roll has over 3,000' on it. I should mention the netting is not a cheap option. And it requires quite a few feet depending on your operation. I plant in long straight rows to maximize my space, making it easier to run irrigation and support the plants with netting. If you utilize another lay out, you may have to think outside the box as to how this support system could work for you. The netting doesn't need to be fastened to the posts. It just needs to be stretched tight over the posts and be taunt. You do not want any give in the netting. Again, it's there to be a grid that the plants grow through and will keep them upright. There is more stretch to the netting then you'd think, so test it's limitations and if you break a section, have a few zip-ties on hand to repair.
I place 2 levels of netting. I don't measure but I would say the first layer is 15-20" from the ground and the second layer is 34-40" from the ground. Do not stress out too much on how it 'looks'. As long as the netting is tight in a month and a half you will never notice it because you're plants will swallow it up! Occasionally you may have to thread through a side shoot that didn't grow through the grid or add in a post because the plants got too tall the wind forced them over, but you won't have dahlias flopped over on the ground with stems growing at a 90 degree angle.
Supplies can be purchased anywhere. I encourage you to find a produce/orchard/greenhouse/farm supply store near you. Do a google search for your area. For Pennsylvania, there are two known suppliers: Martin's Produce Supply and Nolt's Greenhouse Supply.
I am a person that comes from a production background. Efficiency is key because I'm usually the only person doing all the tasks! Or in the case of growing up on a farm, my family ran a herd of beef cows and farmed a few hundred acres of hay with just us. We didn't hire help and if we did it was because the weather was good and we had a pile of hay to get in the barn. (Yo, we did small square bales. I would estimate nearly 85% was small squares. And if you aren't familiar, this is me basically saying that it was so much work, time and all physical labor. Bales don't stack themselves - well then at least.) But my point is, you quickly figure out ways to be most efficient with your time and effort, as they are both very precious.
This mindset is also applied to growing dahlias. Dahlias are fickle and can be exceptionally challenging to grow. They are needy, hungry, thirsty and their only saving grace is they can't move (but need a lot of support to keep them upright, because they can fall down quickly). But with all their quirks they are so very, very rewarding. They evoke a sense of pride that is unmeasurable when the plants are looking lush and green, upright and full of color. It's truly a beautiful sight to see.
But not all dahlias are created equal.
There are garden varieties, which are bred to stay short, compact, bloom profusely and require no support for enjoyment in your landscape or flower beds. These varieties are not for cut flower production, just ornamental use.
There are show dahlias where the most desirable trait of the plant is the bloom. Some folks grow dahlias just for exhibition. The blooms are judged by a qualified official to a standardized ruleset and awards are given for the best ones. It functions much like any other thing that can be exhibited. i.e: dogs, cattle, vegetables, etc. I will admit to not knowing much about the show world of dahlias but I have grown some of the varieties and they aren't my favorite. The criteria required for a good show bloom, sometimes does not align with a good production bloom. But that does not mean they do not have any merit, it just means they aren't what works well for me.
Then there are what my sister, LeeAnn, and I like to call production dahlias. Which is where the efficiency chatter comes back into play. I do not want to work any harder than I have to to get a plant to perform for me, but there are a few key traits that make the saying 'Work smarter, not harder' come to fruition. The perfect dahlia for me produces many fleshy, easy storing tubers. Those tubers are vigorous and quick to grow when planted out in the field. I.e. - no pre-starting tubers. I just want to be able to plant a sound tuber in the the ground when the soil temperatures are right and it will just grow. Ideally that plant will respond well to a healthy pinch by throwing many strong side laterals and has a robust frame that offers rigidity for the weight it's about to bear. The side shoots produce lots of long, strong cuttable stems with ample space between internodes and will bloom above the leaf canopy. The bloom will be strongly fixed to the stem and at a 45* angle. Notice how I haven't even mentioned anything about the bloom shape, color or size yet? That's because you have to have a good foundation in order to have a production dahlia. Without it, you are having to do more work. Now, I know, you can't sell an ugly bloom. But I have found that 'ugly' is in the eye of the beholder, so I try not to judge the bloom too harshly. Odds are there is someone out there that will absolutely adore it. I also didn't mention anything about the height of the plant. Bigger doesn't always mean better. I have found there are plenty of short stack dahlia varieties that produce the ideal stem length without setting the plant back in production.
Now it is your turn to take this information and really analyze your dahlia plants this season. Are you working harder than you should because the plant wasn't bred to fulfil your need? Is it costing you extra labor to keep the plant up right? Is it costing you extra time stripping laterals and leaves because you had to cut really deep into the plant for your desired stem length? After you do all this is does the bloom head pop off in transit? (That's the most frustrating!) Just things to consider and to help you think outside of the 'but the bloom is so pretty' mindset because in farming its all about efficiency.