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Growing Dahlias (Part 2)

Sorry for the delay! We had a little technical issue... a few of our written blog drafts were deleted and so we had to re-write! Hopefully this post helps boost your confidence with growing Dahlias!

Last blog we discussed some basic parts of growing dahlias, today we'll chat about a couple more complicated things you can do to have a great crop.

If you received or have tubers in a clump, the first thing you should do is split them. We find that splitting tubers is easier in spring than fall because the "eyes" are more visible. Without an eye, your tuber will not grow a plant. The eyes are where the entire plant stems from. Sometimes there is more than one eye on a tuber, sometimes only one. It doesn't matter. As long as there is an eye, a plant can be grown from it. Tubers come in all shapes and sizes, and some are huge and long, some are round and small, it really doesn't matter. Eyes can be found on the top of the tuber near the neck, and are just a little bump that resembles a pimple. In fall they are the same colour as the tuber and tend to blend in. In spring, often as the tubers wake up they bulge a little, turn colour or can even start sprouting. This is why we wait till spring to split our dahlias. It's just easier.

Above is pictures of what the eyes look like in spring (both purple and white) which make them much easier to spot

When splitting your dahlias, all you need to do is make sure it has an eye, and a part of the neck (connects the tuber to the stem). We also try to have a part of the stem(from last season's plant) on every tuber. The original tuber is rarely viable, but you'd be surprised what can all grow. In fact last year after we went through our splitting process, we tossed what we didn't think was viable into a bin. After a few weeks the bin started sprouting and many of our tossed tubers were completely fine! Since we start all of our dahlias inside, they are all growing by the time we plant them out. That way we never have spaces with no dahlias in the field where we accidentally plan a non-viable tuber. We always recommend pre-sprouting your dahlias so you know exactly what is growing and have earlier flowers. If you have the space, you can try planting all of the tubers you split as it will help you learn what can be viable and what won't be.

Above pictures show eyes (circled), where we would split the tubers(lines), and what you're looking for

Once your dahlias start growing whether it's indoors or outdoors, you should pinch them back. It can feel counter intuitive, but pinching them back promotes growth, and ultimately leads to more flowers and a healthier plant. The general rule, is once there are 3-4 sets of leaves, pinch off the top to just above the top set of leaves. If the stem is thick and hollow, try to avoid watering into the hole because this can cause tubers to rot.

If you're looking to multiply your tubers for the upcoming season, you can pre-sprout them and once there is 2-3 sets of leaves, you can cut the entire stem off from the tuber and root it by dipping it in root powder and into damp soil. It can take a little while, but that stem will produce a tuber, and the original tuber will produce new stems.

When pre-starting your dahlias indoors, they don't require much space or soil (we plant about 10 of them in a 10x20 seedling starting tray), but once you plant them outdoors they will require more space and deeper soil. We space our dahlias in double rows that are 9 inches apart, and in the rows we lay them about 12 inches apart.

If you only have a few dahlias, staking them can be as simple as using a heavy duty peony cage, or a tall wooden stake or piece of rebar with some twine. If you have a row, you can stake them together to use less stakes. If you don't plan on using them for cut flowers, you don't have to stake them, but parts of them may topple over. If you don't want to stake them, look for varieties that are shorter.

We hope this helps you get started this spring! We'll have a future dahlia post about disbudding, bugs, and getting ready for winter.


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